The screening and diagnosis of autistic spectrum disorders

Abstract

The Child Neurology Society and American Academy of Neurology recently proposed to formulate Practice Parameters for the Diagnosis and Evaluation of Autism for their memberships. This endeavor was expanded to include representatives from nine professional organizations and four parent organizations, with liaisons from the National Institutes of Health. This document was written by this multidisciplinary Consensus Panel after systematic analysis of over 2,500 relevant scientific articles in the literature. The Panel concluded that appropriate diagnosis of autism requires a dual-level approach: (a) routine developmental surveillance, and (b) diagnosis and evaluation of autism. Specific detailed recommendations for each level have been established in this document, which are intended to improve the rate of early suspicion and diagnosis of, and therefore early intervention for, autism.

Full text

Journal
of
Autism
and
Developmental
Disorders Vol.
29, No. 6,
1999
The
Screening
and
Diagnosis
of
Autistic
Spectrum Disorders
1
Pauline
A.
Filipek,
2,17
Pasquale
J.
Accardo,
3
Grace
T.
Baranek,
4
Edwin
H.
Cook,
Jr.,
5
Geraldine Dawson,
6
Barry Gordon,
7
Judith
S.
Gravel,
8
Chris
P.
Johnson,
9
Ronald
J.
Kallen,
5
Susan
E.
Levy,
10
Nancy
J.
Minshew,
11
Barry
M.
Prizant,
12
Isabelle Rapin,
8
Sally
J.
Rogers,
13
Wendy
L.
Stone,
14
Stuart Teplin,
4
Roberto
F.
Tuchman,
15
and
Fred
R.
Volkmar
16
The
Child Neurology Society
and
American Academy
of
Neurology recently
proposed
to
for-
mulate
Practice
Parameters
for the
Diagnosis
and
Evaluation
of
Autism
for
their memberships.
This endeavor
was
expanded
to
include representatives from nine professional organizations
and
four
parent organizations, with liaisons
from
the
National Institutes
of
Health. This document
was
written
by
this multidisciplinary Consensus Panel after systematic analysis
of
over
2,500
relevant
scientific articles
in the
literature.
The
Panel concluded that appropriate diagnosis
of
autism
requires
a
dual-level approach:
(a)
routine developmental surveillance,
and (b)
diagno-
sis and
evaluation
of
autism. Specific detailed recommendations
for
each level have been
es-
tablished
in
this document, which
are
intended
to
improve
the
rate
of
early suspicion
and
diag-
nosis
of, and
therefore early intervention
for,
autism.
INTRODUCTION
The
synonymous terms
Autistic
Spectrum
Dis-
orders
and
Pervasive
Developmental
Disorders
refer
to a
wide continuum
of
associated cognitive
and
neuro-
behavioral disorders, including,
but not
limited
to,
three
Portions
of
this
manuscript
were
reproduced
with
permission
from
Fil-
ipek,
P. A.
(1999).
The
autistic
spectrum
disorders.
In K. F.
Swaiman
& S.
Ashwal
(Eds.),
Pediatric neurology.
Principles
and
practice
(3rd
ed.,
pp.
606-628).
St.
Louis,
MO:
Mosby
1
With
the
exception
of the first
author,
all
authors
are
listed
in al-
phabetical
order.
2
University
of
California,
Irvine,
Irvine,
California
92717.
3
New
York
Medical
College,
Valhalla,
New
York
10595.
4
University
of
North
Carolina
at
Chapel
Hill,
Chapel
Hill,
North
Carolina
27599.
5
University
of
Chicago,
Chicago,
Illinois
60637-1513.
6
University
of
Washington,
Seattle,
Washington
98195.
7
Johns
Hopkins
University
School
of
Medicine,
Baltimore,
Maryland
21218.
8
Albert
Einstein
College
of
Medicine,
Bronx,
New
York.
9
University
of
Texas
Health
Science
Center
at San
Antonio,
San
Antonio,
Texas
78284-8200.
core-defining
features: impairments
in
socialization,
impairments
in
verbal
and
nonverbal communication,
and
restricted
and
repetitive patterns
of
behaviors
(American Psychiatric Association [APA], 1994).
Many
terms have been used over
the
years
to
refer
to
these
disorders,
(e.g.,
infantile
autism, pervasive
de-
velopmental disorder- residual type, childhood schizo-
phrenia,
and
autistic psychoses). Although autism
was
10
University
of
Pennsylvania
School
of
Medicine,
Philadelphia,
Pennsylvania.
11
University
of
Pittsburgh
School
of
Medicine,
Pittsburgh,
Penn-
sylvania.
12
Brown
University,
Providence,
Rhode
Island
02912.
13
University
of
Colorado
Health
Science
Center,
Denver,
Colorado
80262.
14
Vanderbilt
University
Medical
Center,
Nashville,
Tennessee.
15
University
of
Miami
School
of
Medicine,
Coral
Gables,
Florida.
16
Yale
University,
New
Haven,
Connecticut
06520.
17
Address
all
correspondence
to
Pauline
A.
Filipek,
Departments
of
Pediatrics
and
Neurology,
University
of
California,
Irvine,
College
of
Medicine,
UCI
Medical
Center,
Route
81-4482,
101
City
Drive
South,
Orange,
California
92868-3298;
e-mail:
filipek@uci.edu.
439
0162-3257/99/1200-0439$
16.00/0
©
1999
Plenum
Publishing
Corporation
KEY
WORDS:
Practice
parameters
diagnosis
and
evaluation
of
autism;
dual-level
approach.

440
Filipek
et al.
first
described over
50
years
ago by
Kanner (1943),
our
improved understanding
of
this complex disorder
has
emerged over
the
past
two
decades, and, despite
the re-
cent intense
focus
on
autism,
it
continues
to be an art
and
science
in
rapid evolution.
The
terms autism, autistic,
and
autistic spectrum
disorders
are
used interchangeably throughout this paper
and
refer
to the
broader umbrella
of
pervasive develop-
mental disorders (PDD), whereas
the
specific
term Autis-
tic
Disorder
is
used
in
reference
to the
more restricted
criteria
as
defined
by the
Diagnostic
and
Statistical Man-
ual
of
Mental Disorders,
4th
Edition (DSM-IV; APA,
1994).
The
complexity
and
wide variability
of
symptoms
within
the
autistic
spectrum
point
to
multiple
etiologies
which
are
currently grouped together under this diag-
nostic umbrella because
of the
similar core behavioral
symptomatology.
The
autistic spectrum disorders
are not
rare disor-
ders,
but
instead
are
more prevalent
in the
pediatric pop-
ulation than cancer, diabetes, spina
bifida,
and
Down syn-
drome.
The
earliest epidemiology studies noted
a
prevalence
of
Infantile Autism
of 4-5 per
10,000
which
is
approximately
1 in
every
2,000
people (Lotter, 1966).
With
the
broader clinical phenotype
and
improved clin-
ical recognition,
the
prevalence estimates have increased
to
10-20
per
10,000,
or one in
every
500 to
1,000 peo-
ple
(Bryson, 1996; Bryson, Clark,
&
Smith, 1988a; Ehlers
&
Gillberg, 1993; Gillberg,
Steffenburg,
&
Schaumann,
1991; Ishii
&
Takahasi, 1983; Sugiyama
&
Abe, 1989;
Wing
&
Gould, 1979). Recent statistical analyses
by the
Commonwealth
of
Massachusetts Department
of
Public
Health indicate
a
prevalence rate
in the
Zero-to-Three
Early Intervention Program
of 1 in 500
children (Tracey
Osbahr, Massachusetts DPH, personal communication,
March
1999).
These higher prevalence rates imply that
there
are
between
60,000
and
115,000
children under
15
years
of age in the
United States
who
meet diagnos-
tic
criteria
for
autism (Rapin, 1997). Most recently, Baird
et
al.
(1999)
found
a
prevalence rate
of
30.8 cases
per
10,000
of
Autistic Disorder
(1 in 333
children), with 27.1
additional
cases
per
10,000
for the
autistic spectrum dis-
orders. These prevalence rates
are
significantly higher
than
those noted
in
previous reports
and
require
reconfi-
mation
in a
future
study. However,
the
notion
of
these
markedly increasing prevalence rates
further
affirms
the
need
for
improved early screening
and
diagnosis.
The
overall ratio
of
males
to
females
with
autism
has
traditionally
been reported
at
approximately
3:1 to 4:1
(Lotter, 1966; Wing
&
Gould, 1979). However,
the
ratio
seems
to
vary with
IQ,
ranging
from
2:1
with severe dys-
function
to
more than
4:1 in
those with average
IQ
(Bryson,
1997; Ehlers
&
Gillberg, 1993; Wing
&
Gould,
1979). Some
feel
that
fewer
females
with normal
IQ are
diagnosed with autism because they
may be
more socially
adept than males
with
similar
IQ
(McLennan, Lord,
&
Schopler, 1993; Volkmar, Szatmari,
&
Sparrow, 1993b).
Every health
care
or
educational agency serving
young
children
can
expect
to see
children with autism.
Although
symptoms
of
autism
may be
present
in the
first
year
of
life
in
children
who are
diagnosed later,
and
symptoms
are
virtually always present before
the age of
3
years, autism
is
often
not
diagnosed until
2 to 3
years
after
symptoms appear. Individuals with autism also
often
remain undiagnosed
or
inaccurately diagnosed.
Many
clinicians hesitate
to
discuss
the
possibility
of a
diagnosis
of
autism
with
parents
of
young children even
when
some
symptoms
are
present,
due to
concerns
about
family
distress,
the
possible adverse
effects
of
labeling
a
child,
the
possibility
of
being incorrect,
or the
hope
that
the
symptoms
will
reverse over time. However,
it is
believed that
the
positive outcomes
of
accurate diagno-
sis
far
outweigh
the
negative
effects,
and
families uni-
versally express
the
desire
to be
informed
as
early
as
possible (Marcus
&
Stone, 1993).
In
actuality,
the
advantages
of
early diagnosis
of
autism
are
many
and
include
earlier
educational plan-
ning
and
treatment, provision
for
family
supports
and
education, reduction
of
family
stress
and
anguish,
and
delivery
of
appropriate medical care
to the
child (Cox
et
al., 1999). Screening activities
are
crucial
to
early
diagnosis.
The
purpose
of
screening
is to
identify
chil-
dren
at
risk
for
autism
as
soon
as
possible
so
that they
can be
rapidly referred
for
full
diagnostic assessment
and
needed interventions.
The
press
for
early identi-
fication
comes
from
evidence gathered over
the
past
10
years that intensive early intervention
in
optimal
educational settings results
in
improved outcomes
in
most young children with autism, including speech
in
75%
or
more
and
significant increases
in
rates
of de-
velopmental progress
and
intellectual performance
(Dawson
&
Osterling, 1997; Rogers, 1996,
1998).
However,
these
kinds
of
outcomes have been docu-
mented only
for
children
who
receive
2
years
or
more
of
intensive intervention services during
the
preschool
years (Anderson, Avery, Dipietro, Edwards,
&
Chris-
tian, 1987; Anderson, Campbell,
&
Cannon, 1994;
Fenske, Zalenski, Krantz,
&
McClannahan, 1985;
Hoyson, Jamieson,
&
Strain, 1984; Lovaas, 1987;
McEachin, Smith,
&
Lovaas, 1993;
Ozonoff
&
Cath-
cart,
1998).
Thus, early screening
and
early identifi-
cation
are
crucial
for
improving outcomes
of
children
with
autism (Hoyson
et
al., 1984; McEachin
et
al.,
1993; Rogers, 1996, 1998,
in
press; Rogers
&
Lewis,
1989; Sheinkopf
&
Siegel, 1998).
Howlin
and
Moore (1997) described
the
diagnostic
experiences
of
almost 1,300 families with children
with

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
441
autism
from
the
United Kingdom.
The
average
age at
diagnosis
in
this study
was not
until
6
years (while
in
the
U.S.
the
average
is 3 to 4
years
of
age), despite
the
fact
that most
if not all
parents
of
children with autism
had a
sense that something
was
wrong
by 18
months
of
age on
average
and
usually
first
sought medical assis-
tance
by 2
years
of
age.
The
U.K. parents reported that
despite
concerns
in at
least
three
different
developmen-
tal
areas,
fewer
than
10%
were given
a
diagnosis
at
ini-
tial
presentation. About
90%
were referred
to
another
professional
(at a
mean
age of 40
months). Twenty-five
percent were nonetheless told "not
to
worry."
In the re-
maining 10%, over half were told
to
return
if
their wor-
ries
persisted,
and the
rest
were
told
that their child
"would grow
out of
it."
Of
those families referred
to a
second professional, only
40%
were given
a
formal
di-
agnosis
and 25%
were referred
to yet a
third
or
fourth
professional. Almost
25% of the
families were either
re-
assured
by the
second professional
and
told
not to
worry,
or
their concern
was
acknowledged
but no
further
action
was
taken. Almost
20%
reported that they either
had to
exert considerable pressure
to
obtain
the
referrals
or pay
privately. Over
30% of
parents referred
to
subsequent
professionals reported that
no
help
was
offered
(e.g., with
education,
therapy,
or
referrals
to
parent
support groups),
and
only about
10%
reported that
a
professional
ex-
plained their
child's
problems. Almost half
of the
fam-
ilies
reported that
the
school system
and
other parents
were
the
major source
of
assistance over time, rather
than
the
medical health care community.
Howlin
and
Moore
(1997)
concluded
that
(a)
early
parental concerns about
a
child's development should
be
taken more seriously
by
both primary care
and
special-
ist
professionals, with speedy referrals
to
appropriate
fa-
cilities,
(b)
labels such
as
"autistic tendencies"
or
"fea-
tures"
should
be
avoided
if one is
unable
to
give
a
specific
diagnosis
of
autism,
and
that
(c)
diagnosis
in it-
self
may be a
critical
step
but
will
not
improve progno-
sis
unless combined with practical help
and
support
to
assist parents
in
obtaining treatment
for the
child,
in
order
to
develop skills
and
strategies applicable through-
out
the
child's
life.
lescent Psychiatry, American Academy
of
Family Physi-
cians, American Academy
of
Neurology, American
Academy
of
Pediatrics, American Occupational Therapy
Association, American Psychological Association, Amer-
ican
Psychological Society, American Speech-Language
Hearing Association, Child Neurology Society, Society
for
Developmental
and
Behavioral Pediatrics,
and the
Society
for
Developmental
Pediatrics
for
representa-
tive(s)
from
each organization
with
the
requisite expert-
ise in the
screening
and
diagnosis
of
autism, whether
by
clinical research
or
clinical practice.
Final representatives include Judith
S.
Gravel
(American
Academy
of
Audiology); Edwin
H.
Cook
Jr.
and
Fred
R.
Volkmar (American Academy
of
Child
and
Adolescent Psychiatry); Isabelle Rapin
and
Barry Gor-
don
(American Academy
of
Neurology); Stuart Teplin,
Ronald
J.
Kallen,
and
Chris Plauche Johnson (Ameri-
can
Academy
of
Pediatrics); Grace
T.
Baranek (Amer-
ican Occupational Therapy Association); Sally
J.
Rogers
and
Wendy
L.
Stone (American Psychological Associ-
ation); Geraldine Dawson (American Psychological
So-
ciety); Barry
M.
Prizant (American Speech-Language
Hearing Association); Nancy
J.
Minshew
and
Roberto
F.
Tuchman (Child Neurology Society); Susan
E.
Levy
(Society
for
Developmental
and
Behavioral
Pediatrics);
and
Pasquale
J.
Accardo (Society
for
Developmental
Pediatrics). Representatives were named
from
the
fol-
lowing
associations: Barbara Cutler
and
Susan Good-
man
(Autism National Committee), Cheryl Trepagnier
(Autism
Society
of
America), Daniel
H.
Geschwind
(Cure Autism Now),
and
Charles
T.
Gordon
(National
Alliance
for
Autism Research).
The
National Institutes
of
Health also named liaisons
to
serve
on
this commit-
tee, including Marie Bristol-Power (National Institute
of
Child Health
and
Human Development), Judith
Cooper (National Institute
of
Deafness
and
Communi-
cation Disorders),
Judith
Rumsey (National Institute
of
Mental Health),
and
Giovanna Spinella (National Insti-
tute
of
Neurological Disorders
and
Stroke).
Consensus
was
reached
by
group discussion
in all
cases,
either including
the
entire panel,
or
within
sub-
groups
by
specialities.
DESCRIPTION
OF THE
ANALYTICAL
PROCESS
Selection
of
Consensus
Panel
Filipek
was
named
by the
American Academy
of
Neurology
to
chair
a
committee
to
determine practice
parameters
for
screening
and
diagnosis
of
autism. Nom-
inations were then sought
from
the
American Academy
of
Audiology, American Academy
of
Child
and
Ado-
Literature
Review
Comprehensive computerized literature
searches
of
Medline
(National Library
of
Medicine)
and
PsychINFO
(American
Psychological
Association)
in all
languages
using
the
terms "(autistic
OR
autism
OR
pervasive)
NOT
treatment" produced over
4,000
documents.
The
focus
was on
literature published since 1990 that
re-
ported scientific research,
but
older sources
and
less
stringent
studies were included when relevant.
A
bibli-

442
Filipek
et al.
Pervasive Developmental Disorder.
In
DSM-III, autism
was
also clearly differentiated
from
childhood schizo-
phrenia
and
other psychoses
for the
first
time,
and the
absence
of
psychotic symptoms, such
as
delusions
and
hallucinations,
became
one of the six
diagnostic criteria.
The
revised DSM-III-R (APA, 1987) broadened
the PDD
spectrum
and
narrowed
the
possible diagnoses
to
two,
Autistic
Disorder
and
Pervasive Developmental Dis-
orderNot Otherwise Specified (PDD-NOS).
Currently,
DSM-IV (APA, 1994) includes
five
pos-
sible diagnoses under
the PDD
umbrella (Table
I)
which
are
concordant with
the
International Classification
of
Disease, 10th edition (ICD-10), used primarily abroad
(World Health Organization [WHO], 1992).
The
Broader Phenotype
Although
Allen first coined
the
phrase "autistic
spectrum
disorder" (1988),
the
same year that Wing
wrote
about
the
"autistic continuum" (1988), controversy
still
surrounds this concept
of a
broader clinical pheno-
type. DSM-III (APA, 1980) acknowledged that such
a
continuum
existed,
and
labeled
it
PDD;
the
term Autis-
tic
Disorder
was
reserved
only
for
those with
classical
signs
and
symptoms presenting before
30
months
of
age.
Over
the
past
10
years, however, there
has
been
a
slowly
growing
clinical consensus that
the
umbrella
of
"perva-
sive developmental disorders" does actually represent
an
"autistic spectrum" (Wing, 1997).
For the
first
time,
DSM-IV
criteria included
the
term qualitative
to
describe
the
impairments
within
the
major criteria, defining
a
range
of
impairments rather than
the
absolute presence
or
absence
of a
particular behavior
as
sufficient
to
meet
a
criterion
for
diagnosis.
Table
I. The
Pervasive Developmental (Autistic Spectrum)
Disorders
DSM-IV
Diagnoses
(APA,
1994)
Autistic
disorder
Asperger
disorder
Childhood
disintegrative
disorder
Rett
disorder
PDD-NOS"
Atypical
autism
(no
corresponding
DSM-IV
diagnosis)
ICD-10 Diagnoses
(WHO, 1992, 1993)
Childhood
autism
Asperger syndrome
Other
childhood disintegrative
disorder
Rett
syndrome
Atypical
autism
Other
PDD
PDD,
unspecified
Overactive
disorder
with
mental
retardation with
stereotyped
movements
a
PDD-NOS
=
Pervasive Developmental Disorder-Not Otherwise
Specified.
ography
of
over 2,750 references
was
developed
for
this
review; article abstracts were initially reviewed, fol-
lowed
by the
relevant
articles
in
entirety.
The
review
process
was
expedited
by the
many review
papers
and
meta-analyses developed
for
DSM-IV (APA, 1994),
the
research overview resulting
from
the
National Institutes
of
Health State
of
the
Science Conference
on
Autism
in
1995 (see Bristol
et
al., 1996,
and
accompanying arti-
cles)
and
current review articles, book chapters
and
books (Bailey, Phillips,
&
Rutter, 1996; Bauer, 1995a,
1995b;
D. J.
Cohen
&
Volkmar, 1997; Filipek, 1999;
Minshew, 1996a; Minshew, Sweeney,
&
Bauman, 1997;
Rapin, 1997; Rutter, 1996).
HISTORICAL PERSPECTIVE
Autism from 1943
to
1980
Kanner (1943) first described
a
syndrome
of
"autis-
tic
disturbances" with
case
histories
of 11
children
who
presented between
the
ages
of 2 and 8
years
and who
shared "unique"
and
previously unreported patterns
of
behavior including social remoteness, obsessiveness,
stereotypy,
and
echolalia.
After
its
initial description,
autism
was
poorly ascertained during
the
middle decades
of
the
20th century.
In
DSM-I (APA, 1952)
and
DSM-
II
(APA, 1968), "psychotic reactions
in
children, mani-
festing
primarily autism," were classified under
the
terms
"schizophrenic reaction
or
schizophrenia, childhood
type"
(p.
28).
Despite this early
but
persisting view
of
autism
as
a
psychosis, several prominent research groups formu-
lated
the
first
set of
diagnostic criteria
for
this disorder
by
the
1970s (Ritvo
&
Freeman, 1978; Rutter
&
Hersov,
1977). With DSM-III (APA,
1980),
the
term Pervasive
Developmental
Disorders
(PDD)
was
first used
to
describe disorders
characterized
by
distortions
in the
development
of
mul-
tiple
basic psychological
functions
that
are
involved
in
the
development
of
social
skills
and
language,
such
as
attention,
perception, reality testing,
and
motor move-
ment
. . . The
term Pervasive Developmental Disorder
was
selected because
it
describes most accurately
the
core clinical disturbance: many basic areas
of
psycho-
logical
development
are
affected
at the
same time
and
to a
severe degree.
(p. 86)
Under this
new PDD
umbrella,
the
possible diagnoses
included,
for the
first
time,
the
term Infantile
Autism
(with
onset prior
to age 30
months)
as
well
as
Childhood
Onset Pervasive Developmental Disorder (with onset
after
age 30
months), each
further
subclassified into "Full
Syndrome Present"
or
"Residual State,"
and
Atypical

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
443
The
currently recognized clinical phenotype
in-
cludes children with milder,
but
nonetheless unequivo-
cal,
social,
communication,
and
behavioral deficits. Many
high-functioning
autistic children
are
diagnosed after
presentation
to
clinics specializing
in
learning disabili-
ties
or
Attention-Deficit/Hyperactivity Disorder (ADHD)
(Porter,
Goldstein, Galil,
&
Carel, 1992). Almost
15%
of
previously undiagnosed children receiving special
ed-
ucation services
met
criteria
for
DSM-III-R Autistic Dis-
order
in one
series (Deb
&
Prasad, 1994). Autistic
"traits"
were
also
retrospectively found
in
almost
one
quarter
of
2,201 adults previously diagnosed with various learning
disabilities
(Bhaumik, Branford, McGrother,
&
Thorp,
1997).
Questionnaires
devised
to
specifically
diagnose
ADHD will
not
identify autistic symptomatology,
and
74% of
children with high-functioning autism
in
another
series
had
erroneously been previously diagnosed with
ADHD despite clear differences
in
their social compe-
tence, cognitive development,
and
restricted range
of ac-
tivities
(Jensen, Larrieu,
&
Mack,
1997).
PRESENTING SIGNS
AND
SYMPTOMS
OF
THE
AUTISTIC SPECTRUM DISORDERS
All
children
on the
autistic spectrum demonstrate
the
same
core
deficits,
in (a)
reciprocal social interactions
and (b)
verbal
and
nonverbal communication, with
(c)
restricted
and
repetitive behaviors
or
interests (APA,
1994).
There
is,
nonetheless, marked variability
in the
severity
of
symptomatology across patients,
and
level
of
intellectual function
can
range from profound mental
re-
tardation through
the
superior range
on
conventional
IQ
tests.
The
DSM-IV
criteria
for
Autistic Disorder
are
pre-
sented
in
Table
II and are
described below
for
each
neurobehavioral domain.
The
symptoms
and
signs rep-
resent
a
summary
of
clinical features which
are
discussed
in
greater
detail
in the
DSM-IV (APA, 1994),
in the
monograph edited
by
Rapin (1996c),
in the
Wing
Autis-
tic
Disorders Interview Checklist- Revised (Wing,
1996),
and in
numerous additional publications describing
the
clinical presentation
of the
Autistic Spectrum Disorders
(Allen, 1991; Bauman,
Filipek,
&
Kemper, 1997;
D. J.
Cohen
&
Volkmar, 1997;
Filipek,
1999; Lord
&
Paul,
1997; Minshew,
1996a;
Rapin, 1997).
Autistic
Disorder
(DSM-IV
A1). Qualitative Impairment
in
Social
Interactions
It is
important
to
understand that these criteria refer
to a
qualitative impairment
in
reciprocal social interac-
tions,
and not to the
absolute lack
of
social behaviors.
The
behaviors under this rubric range
from
total lack
of
awareness
of
another person,
to eye
contact which
is
present
but not
used
to
modulate social interactions.
The
outline
for
this section follows
the
DSM-IV outline
for
the
criteria
for
Autistic Disorder (Table
II)
(APA, 1994).
Table
II.
Diagnostic Criteria
for
299.00
Autistic
Disorder
(APA,
1994)
a
A.
A
total
of six (or
more) items
from
(1), (2),
and
(3),
with
two
from
(1),
and at
least
one
each
from
(2) and
(3):
(1)
qualitative impairment
in
social interaction,
manifest
by at
least
two of the
following:
a)
marked impairment
in the use of
multiple
nonverbal
behaviors,
such
as
eye-to-eye gaze,
facial
expression,
body
postures,
and
gestures,
to
regulate social interac-
tion;
b)
failure
to
develop peer
relationships
appropriate
to
developmental
level;
c) a
lack
of
spontaneous seeking
to
share
enjoyment,
inter-
ests,
or
achievements
with
other people (e.g.,
by
lack
of
showing,
bringing
or
pointing
out
objects
of
interest);
d)
lack
of
social
or
emotional reciprocity
(2)
qualitative
impairment
in
communication,
as
manifest
by at
least
one of the
following:
a)
delay
in, or
total lack
of, the
development
of
spoken
language
(not accompanied
by an
attempt
to
compen-
sate
through
alternative
modes
of
communication
such
as
gesture
or
mime);
b) in
individuals
with
adequate speech, marked impairment
in
the
ability
to
initiate
or
sustain
a
conversation
with
others;
c)
stereotyped
and
repetitive
use of
language,
or
idiosyn-
cratic language;
d)
lack
of
varied, spontaneous make-believe,
or
social imi-
tative
play appropriate
to
developmental level.
(3)
restrictive repetitive
and
stereotypic patterns
of
behavior,
interests,
and
activities,
as
manifested
by at
least
one of
the
following:
a)
encompassing preoccupation
with
one or
more stereo-
typed
and
restricted patterns
of
interest
that
is
abnormal
either
in
intensity
or
focus;
b)
apparently
inflexible
adherence
to
specific
nonfunc-
tional
routines
or
rituals;
c)
stereotyped
and
repetitive motor mannerisms (e.g.,
hand
or
finger
flapping or
twisting,
or
complex whole-body
movements);
d)
persistent preoccupation
with
parts
of
objects.
B.
Delays
or
abnormal
functioning
in at
least
one of the
following
areas, with onset prior
to age 3
years:
(1)
social interaction,
(2)
language
as
used
in
social communication,
or (3)
symbolic
or
imaginative play.
C. The
disturbance
is not
better accounted
for by
Rett's Disorder
or
Childhood Disintegrative Disorder.
°
Reprinted
with
permission
from
the
Diagnostic
and
Statistical
Manual
of
Mental
Disorders (4th ed.,
pp.
70-71
Washington,
DC:
American
Psychiatric
Association, 1994.

444
Filipek
et al.
(Ala). Marked Impairment
in the Use
of
Multiple
Nonverbal Behaviors, Such
As
Eye-to-Eye Gaze,
Fa-
cial Expression,
Body
Posture,
and
Gestures
to
Regu-
late Social Interaction.
As
infants, some children with
autism
do not
lift
up
their arms
or
change posture
in an-
ticipation
of
being held. They
may not or may
cuddle
or
stiffen
when held,
and
often
do not
look
or
smile when
making
a
social approach. Some children
do
make
eye
contact,
often
only
in
brief glances,
but the eye
contact
is
usually
not
used
to
direct attention
to
objects
or
events
of
interest. Other children make inappropriate
eye
con-
tact,
by
turning someone
else's
head
to
gaze into their
eyes.
Autistic children
often
ignore
a
familiar
or
unfa-
miliar
person
because
of a
lack
of
social
interest.
Some
children
do
make social approaches, although their con-
versational
turn-taking
or
modulation
of eye
contact
is
often
grossly impaired.
At the
opposite extreme
of so-
cial interactions, some children
may
make indiscrimi-
nate
approaches
to
strangers
(e.g.,
may
climb into
the
examiner's
lap
before
the
parent
has
even entered
the
room,
be
unaware
of
psychological barriers,
or be de-
scribed
as a
child
who
continuously
and
inappropriately
"gets
into your face"
in an
intrusive manner).
(Alb).
Failure
to
Develop Peer Relationships
Ap-
propriate
to
Developmental Level. Younger children
may
demonstrate lack
of
interest,
or
even apparent lack
of
awareness
of
peers
or
other children. Some children with
autism have
no
age-appropriate
friends,
and
often
older
children
may be
teased
or
bullied.
A
child
may
want
"friends"
but
usually
does
not
understand
the
concept
of
the
reciprocity
and
sharing
of
interests
and
ideas inher-
ent
in
friendship.
For
example, they might refer
to all
classmates
as
"friends."
One
telling example
is the
child
who
said without compunction, "Oh,
I
have many, many,
twenty-nine
friends,
but
none
of
them like me." Verbal
children
may
have
one
"friend"
but the
relationship
may
be
very limited
or may
focus only
on a
similar circum-
scribed interest, such
as a
particular computer game.
Often,
children gravitate
to
adults
or to
older
peers,
in
which
case
they play
the
role
of a
follower,
or to
much
younger
peers,
where they become
the
director.
In
either
case,
the
demands
on
social reciprocity
are
much less
compared
to
interactions with
age-appropriate
peers.
(A1c).
A
Lack
of
Spontaneous Seeking
to
Share
En-
joyment,
Interests,
or
Achievements with Other People
(e.g.,
by a
Lack
of
Showing, Bringing,
or
Pointing
Out
Objects
of
Interest).
As
infants, some children with
autism
do not
reciprocate
in lap
play,
but
rather either
hold
the
parent's arms
as the
parent performs
the
game
in
a
mechanical fashion,
or
insist that
the
parent watch
the
child perform
the
game. Regardless,
the
character-
istic give-and-take
in lap
play that
is
seen
in
typically
developing
children
by the end of the
first
year
is
often
missing.
They
often
do not
point things
out or use eye
contact
to
share
the
pleasure
of
seeing something with
another person, which
is
called
joint
attention.
(A1d).
Lack
of
Social
or
Emotional Reciprocity.
Some children with autism show
no
interest
in
other chil-
dren
or
adults,
and
tend
to
play alone
by
themselves away
from
others. Others play with adults nearby,
or sit on the
outskirts
of
other children's play
and
either engage
in
parallel play
or
simply watch
the
other children. Some
children involve other children
in
designated,
often
repetitive play,
but
often only
as
"assistants"
without
heeding
any
suggestions
from
the
other children. Some
tend
to
serve
in the
passive
role
in
other
children's
play,
for
example
as the
baby
in a
game
of
"house,"
and
sim-
ply
follow
others' directions. Other children
may
seek
out
one
specific child with whom there
is a
limited soli-
tary
interest that dominates
the
entire relationship.
(A2).
Qualitative Impairment
in
Communication
The
communication impairments seen
in the
autis-
tic
spectrum
are far
more complex than presumed
by
simple
speech delay
and
share some similarities with
the
deficits seen
in
children with developmental lan-
guage disorders
or
specific language impairments
(Allen
&
Rapin, 1992). Expressive language function
across
the
autistic spectrum ranges from complete
mutism
to
verbal fluency, although
fluency
is
often
ac-
companied
by
many semantic (word meaning)
and
ver-
bal
pragmatic (use
of
language
to
communicate) errors.
Young
autistic children, even
if
verbal, almost univer-
sally
have comprehension deficits,
in
particular deficits
in
understanding higher order complex questions.
Deficits
in
pragmatics,
the use of
language
to
commu-
nicate
effectively,
are
also
almost universally present.
Some children with autism
do not
respond
to
their
names when called
by a
parent
or
other favored care-
taker,
and
often
they
are
initially presumed
to be se-
verely hearing-impaired. This syndrome, verbal audi-
tory
agnosia (VAA),
is
similar
to
adult-onset acquired
word deafness, with
one
very important
exception:
adults
with acquired word
deafness
remain
fluent
be-
cause their language
has
been overlearned, whereas
children
with autism
with
either developmental
VAA
or
acquired
VAA
with
an
epileptiform aphasia usually
are
mute (Rapin
&
Allen, 1987).
(A2a).
Delay
in, or
Total
Lack
of,
the
Development
of
Spoken Language (Not Accompanied
by an
Attempt
to
Compensate Through
Alternative
Modes
of
Com-
munication Such
As
Gesture
or
Mime).
In
early
infancy,
some children with autism
do not
babble
or use any

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
445
other communicative vocalizations,
and are
described
as
very quiet babies. Some children have absolutely
no
spoken language when speech should
be
developing,
and
also
fail
to
compensate
with facial
expressions
or
gestures.
A
typically developing
infant
or
toddler
may
pull
his
mother over
to a
desired object,
but
then will
clearly point
to the
object while looking
at the
mother's
face.
In
contrast,
a
characteristic behavior
of
many chil-
dren with autism
is to
mechanically
use
another
per-
son's
hand
to
indicate
the
desired object,
often
called
"hand over hand pointing." Some children even throw
another's
arm up
towards
the
desired object that
is out
of
reach, without
any
communicative pointing, gestur-
ing,
or
vocalizations. Other "independent" children
make
no
demands
or
requests
of the
parents,
but
rather
learn
to
climb
at a
young
age and
acquire
the
desired
object
for
themselves.
(A2b).
In
Individuals with
Adequate
Speech,
Marked
Impairment
in the
Ability
to
Initiate
or
Sustain
a
Conversation with Others. Some children
with
autism
speak relatively
fluently,
but are
unable
to
engage
in a
conversation, defined
as two or
more parties communi-
cating
in a
give-and-take fashion
on a
mutually
agreed
upon
topic.
In a
conversation,
Partner
A
makes
a
state-
ment
in
turn
on the
given topic that
is
directed
at
Part-
ner B, who
then makes another statement directed back
at
Partner
A,
which
is
continued over more than
one
cycle
of
turn-taking. Questions
may be
included,
but
they
are
obviously
not the
dominant sentence structure used
in
conversation.
A
hallmark
of
verbally
fluent
autistic
children
is
their inability
to
initiate
or
sustain
a
conver-
sation
on a
topic
of
mutual interest, although they
may
be
able
to
respond relatively well
to, or ask a
myriad
of
questions,
or
talk "at" another person
in a
monologue
or
soliloquy about their favorite topic.
(A2c).
Stereotyped
and
Repetitive
Use
of
Language,
or
Idiosyncratic Language.
A
hallmark
of
autistic speech
is
immediate
or
delayed echolalia. Immediate echolalia
refers
to
immediate repetition
of
words
or
phrases spo-
ken
by
another—the children
are
simply repeating
ex-
actly what
was
heard without formulating their
own
lan-
guage.
It is
important
to
realize that immediate echolalia
is a
very crucial aspect
of
normal language development
in
infants under
the age of 2
years.
It
becomes
patho-
logic when
it is
still present
as the
sole
and
predominant
expressive language after
the age of
about
24
months,
and
can
often
be
present throughout
the
preschool
or
school-age
years
in
children with autism.
It is
impera-
tive
to
differentiate
speech
that consists predominantly
of
immediate echolalia
from
the
more
classic
picture
of
immediate echolalia progressing rapidly
to
spontaneous
phrase speech
in
typically developing toddlers. Delayed
echolalia
or
scripts refer
to the use of
ritualized phrases
that have been memorized (e.g.,
from
videos, television,
commercials,
or
prior overheard conversations).
The
ori-
gin
of
this
stereotypic
language
does
not
necessarily
have
to be
clearly identifiable. Many older children with
autism
incorporate
the
scripts
in
appropriate conversa-
tional
context, which
can
give much
of
their speech
a
"rehearsed"
and
often
more
fluent
quality relative
to the
rest
of
their spoken language. Children also show
diffi-
culties with pronouns
or
other words that change
in
meaning
with context,
and
often
reverse pronouns
or
refer
to
themselves
in the
third person
or by
name.
Others
may use
literal idiosyncratic phrases
or
neolo-
gisms. Verbal children with autism
may
speak
in
very
detailed
and
grammatically correct phrases, which
are
nonetheless repetitive, concrete,
and
pedantic.
If a
child's
answers
to
questions seem
to
"miss
the
point,"
further
history
and
conversation should
be
elicited with
the
child,
as
this
is
also
a
hallmark
of
autistic language
deficits.
These children typically answer factual ques-
tions correctly
and
appropriately,
but
when asked
a
ques-
tion that requires understanding concepts
or
concept for-
mation,
they give details that
are
often
only tangentially
related
to the
actual
question.
(A2d).
Lack
of
Varied, Spontaneous Make-Believe,
or
Social Imitative Play Appropriate
to
Developmental
Level. Some children
with
autism
do not use
miniature
objects, animals,
or
dolls appropriately
in
pretend play.
Others
use the
miniatures
in a
repetitive mechanical
fashion
without evidence
of
flexible representational
play.
Some highly verbal children
may
invent
a
fantasy
world
which
becomes
the
sole
focus
of
repetitive play.
A
classic example
of the
lack
of
appropriate play
is the
verbal autistic preschooler
who
"plays"
by
repeatedly
reciting
a
soliloquy
of the old
witch scene verbatim
from
Beauty
and the
Beast
while manipulating dollhouse
characters
in
sequence precisely according
to the
script.
When given
the
same miniature figures
and
dollhouse,
but
instructed
to
play something other than Beauty
and
the
Beast,
this same child
is
incapable
of
creating
any
other play scenario.
(A3).
Restricted, Repetitive,
and
Stereotypic
Patterns
of
Behaviors,
Interests,
and
Activities
Again,
this category
of
stereotyped behaviors
and
interests,
like
the
previous ones, encompasses qualitative
deficits
in
several behaviors.
(A3a).
Encompassing Preoccupation with
One or
More
Stereotypic
and
Restricted
Patterns
of
Interest
That
Is
Abnormal
in
Intensity
or
Focus. Some verbal
children with autism
ask the
same question repeatedly,
regardless
of
what reply
is
given,
or
engage
in
highly

446
Filipek
et al.
repetitive perseverative play. Others
are
preoccupied
with
unusual special interests.
For
example, many chil-
dren
are
fascinated with dinosaurs,
but
children with
autism
may not
only amass exhaustive facts about every
conceivable type
of
dinosaur,
but
also about which
mu-
seums house which particular fossils,
and so
forth; these
children will often repeatedly
"share"
their knowledge
with
others regardless
of the
others'
interest
or
sugges-
tions
to the
contrary.
Some
autistic
preschoolers
are
zealous fans
of
Wheel
of
Fortune
or
Jeopardy, even
when
still preverbal
or
minimally verbal; this unusual
interest
in a
preschool child
is
considered
by
many
to
be a
hallmark
of
autism (Allen, 1991).
(A3b).
Apparently Inflexible Adherence
to
Specific
Nonfunctional
Routines
or
Rituals. Many children
with
autism
are so
preoccupied with
"sameness"
in
their
home
and
school
environments
or
with routines, that lit-
tle can be
changed without prompting
a
tantrum
or
other
emotional disturbance. Some may,
for
example, insist
that
all
home furnishings remain
in the
same
position,
or
that
all
clothing
be of a
particular color,
or
that only
one
specific
set of
favored sheets
be on the
bed. Others
may
eat
only
from
a
specific plate when sitting
in a
spe-
cific
chair
in a
specific room, which
may not
necessar-
ily
be the
kitchen
or
dining room. Some children
may
insist
on
being naked while
in the
home,
but
insist
on
wearing
shoes
to the
dinner table. This inflexibility
may
also extend
to
familiar routines,
for
example, taking only
a
certain route
to
school,
or
entering
the
grocery store
only
by one
specific door,
or
never stopping
or
turning
around
once
the car
starts moving. Many parents
may
either
not be
aware that they
are
following certain ritu-
als to
avoid
an
emotional upheaval,
or may be
aware
but
too
embarrassed
to
volunteer such information.
Within this context, some children have distinct behav-
ioral repertoires that they self-impose
to
sustain same-
ness,
even when
not
imposed externally.
By
adulthood,
many
of
these rituals
may
evolve
to
more classic
obsessive-compulsive symptoms, including hoarding
unusable
or
broken objects,
or
repetitively whispering
words
or
phrases
to
themselves.
(A3c).
Stereotyped
and
Repetitive Motor Manner-
isms
(e.g.,
Hand
or
Finger
Flapping
or
Twisting
or
Complex
Whole-Body Movements). Some children will
have obvious stereotypic motor movements, such
as
hand clapping
or arm
flapping whenever excited
or
upset, which
is
pathologic
if it
occurs
after
the age of
about
2
years. Running aimlessly, rocking, spinning,
bruxism, toe-walking,
or
other
odd
postures
are
com-
monly
seen
in
children with autism. Others
may
simply
repetitively
tap the
back
of
their hand
in a
less obtru-
sive manner.
It has
been noted that,
in
higher
function-
ing
youngsters,
the
stereotypic movements
may
become
"miniaturized"
as
they
get
older
into more socially
ac-
ceptable
behaviors, such
as
pill-rolling (Bauman,
1992a;
Rapin,
1996c).
It is
also important
to
realize that
not all
children with autism have repetitive motor movements.
(A3d).
Persistent
Preoccupation
with
Parts
of
Objects.
Many children demonstrate
the
classic
behav-
ior of
lining
up
their toys, videotapes,
or
other favored
objects,
but
others
may
simply
collect
"things"
for no
apparent purpose. Many engage
in
repetitive actions,
such
as
opening
and
closing doors, drawers,
or
flip-top
trash cans,
or
turning light switches
off and on.
Others
are
fascinated
and
repetitively flick strings,
elastic
bands,
measuring
tapes,
or
electric
cords.
Younger
chil-
dren
with autism
are
often particularly fascinated with
water,
and
they especially
enjoy
transferring water
repetitively
from
one
vessel into another. Some
may
taste
or
smell items. Others love spinning objects,
and
may
either spend long periods spinning
the
wheels
of
a toy car or
watching ceiling fans,
or
spinning them-
selves until they
fall
from
dizziness. Some children will
often
look
at
objects
out of the
corner
of
their
eyes.
Asperger
Disorder
Unbeknownst
to
each
other,
the
year after
Kanner's
(1943)
first
description
of
autism,
a
pediatrician named
Asperger (1991/1944)
also
described
four
children
with
"autistic psychopathy,"
who had
presumably milder
autistic
behaviors
and
normal
IQ.
This report
written
in
German
was not
widely known until
the
1980s (Wing,
1981b).
The
diagnostic term
was
included
for the
first
time
in
DSM-IV (APA, 1994),
and the
criteria
for the
qualitative impairments
in
social
interaction,
and re-
strictive
and
repetitive patterns
of
behaviors
and
activi-
ties
are
identical
to
those
for
Autistic Disorder. This
di-
agnostic category
is
clearly
in
evolution and,
as
discussed
in
Schopler, Mesibov,
and
Kunce (1998),
it is
unclear
whether
it
will remain
a
valid syndrome separate
from
autism.
In
contrast
to the
Autistic Disorder criteria which
include
deficits
in
verbal
and
nonverbal communication
and
play, Asperger
criteria
currently
state
that
there
is no
evidence
of
"clinically significant" language delay, such
that
the
child used single words
by age 2
years,
and
com-
municative
phrases
by age 3
years (APA,
1994).
(Note
that
these criteria
for
language delay
are
much laxer than
those recommended
for
referral
in the
current guidelines.)
Normal
or
near-normal
IQ is
also
the
rule, including self-
help skills, "adaptive behavior (other than
in
social
in-
teraction),
and
curiosity about
the
environment
in
child-
hood."
The
lack
of
clear language deviance usually leads

Screening
and
Diagnosis
of
Autistic Spectrum
Disorders
447
to
later clinical recognition than with other autistic spec-
trum disorders, which
is
presumably
due to the
normal
or
near-normal adaptive behavior early
in
life
(Volkmar
&
Cohen, 1991). Yet,
the
language
in
Asperger's
is
clearly
not
typical
or
normal. Individuals with Asperger
disorder usually have pedantic
and
poorly modulated
speech, poor nonverbal pragmatic
or
communication
skills,
and
intense preoccupations
with
circumscribed top-
ics
such
as the
weather
or
railway timetables (Ghaziud-
din
&
Gerstein, 1996; Klin, Volkmar, Sparrow, Cicchetti,
&
Rourke, 1995; Wing, 198l
a).
Their speech
is
often
concrete
and
literal,
and
their answers
often
"miss
the
point."
Some
clinicians have mislabeled individuals with
this speech pattern
as
having
a
Semantic-Pragmatic Lan-
guage
Disorder rather than Asperger's
or
autism (Bishop,
Hartley,
&
Weir, 1994; Bishop, 1989; Gagnon, Mottron,
&
Joanette, 1997). However, this diagnosis
of a
language
disorder
is not an
appropriate substitution
for the
diag-
nosis
of
autism,
as it
does
not
account
for the
social
deficits
and
restrictive, repetitive interests.
Socially, individuals with Asperger disorder
are
usually unable
to
form friendships. Because
of
their
naive, inappropriate one-sided social interactions, they
are
also often ridiculed
by
their peers.
Often
they
cease
their attempts because
of the
cruel ridicule,
and
remain
extremely socially isolated. Yet, they honestly desire
success
in
interpersonal relationships,
and are
often
quite
puzzled when they
do not
succeed (Bonnet
&
Gao,
1996).
They
often
have both
fine
and
gross motor
deficits,
including clumsy
and
uncoordinated movements
and
odd
postures (Asperger, 1991/1944;
Klin
et
al.,
1995; Wing, 1981a). However, motor apraxia
is an in-
consistent finding,
as
formal tests
of
motor abilities
do
not
differentiate
high-functioning
autism
from
Asperger
disorder (Ghaziuddin, Butler, Tsai,
&
Ghaziuddin, 1994;
Manjiviona
&
Prior, 1995).
The
validity
of
Asperger disorder
as a
discrete
di-
agnostic entity distinct
from
high-functioning (verbal)
autism remains controversial (Kurita, 1997; Schopler,
1996; Schopler
et
al., 1998; Volkmar
et
al., 1996). Clin-
ically,
the
diagnosis
of
Asperger disorder
is
often
given
as an
alternative, more acceptable, "A-word"
to
high-
functioning
children with autism (Bishop, 1989). There
are
multiple partially overlapping clinical criteria cur-
rently
in use
around
the
world
for the
diagnosis
of As-
perger disorder, which adds
to the
confusion
(APA, 1994;
Attwood, 1998; Gillberg
&
Gillberg, 1989; 1995; Szat-
mari, Bremner,
&
Nagy, 1989; Wing, 1981a; WHO,
1992,
1993).
The
similarity
and
overlap
of
signs
and
symptoms
of
Asperger's
with
the
Syndrome
of
Nonver-
bal
Learning Disabilities
further
expands
the
spectrum
of
these developmental disorders (Harnadek
&
Rourke,
1994;
Klin
et
al., 1995; Rourke, 1989a, 1989b; Voeller,
1986).
However, again,
a
diagnosis
of a
learning dis-
ability
is not an
appropriate substitution
for a
diagnosis
of
autism,
as all too
often
it
does
not
account
for the
social deficits
and
restrictive, repetitive interests.
To add
to the
confusion,
a
recent retrospective review
of the
orig-
inal
four
Asperger cases (1991/1944) reported that these
children
actually meet current DSM-IV (APA 1994) cri-
teria
for
Autistic Disorder (Miller
&
Ozonoff,
1997).
As
DSM-IV
is now
written,
if
criteria
for
Autistic Disorder
are
met, this precludes
a
diagnosis
of
Asperger disorder.
Childhood Disintegrative
Disorder
Childhood Disintegrative Disorder (CDD) refers
to
the
rare occurrence
of
normal early development until
at
least
age 24
months, followed
by a
rapid neurodevelop-
mental
regression that results most
often
in
autistic symp-
tomatology. CDD, previously called Heller's syndrome,
dementia
infantilis
or
disintegrative psychosis, usually
occurs between
36 and 48
months
of age but may
occur
up
to 10
years
of
age. There have been only
a
hundred
or so
reports
of CDD in the
literature (Volkmar, Klin,
Marans,
&
Cohen, 1997; Volkmar
&
Rutter,
1995).
The
hallmark
signs include
the
loss
of
previously normal lan-
guage, social, play,
or
motor skills,
and
frequently
in-
clude
the
onset
of
restrictive repetitive behaviors,
all
typ-
ical
of
autism (APA, 1994).
CDD is
usually associated
with
more severe autistic symptoms than
is
early-onset
autism,
including
profound loss
of
cognitive skills
re-
sulting
in
mental retardation (Catalano, 1998; Evans-
Jones
&
Rosenbloom, 1978; Hoshino
et
al., 1987; Short
&
Schopler, 1988; Tuchman
&
Rapin, 1997; Volkmar
&
Rutter,
1995).
A
recent review
of CDD
noted
a 4:1
male
predominance, mean
age of
onset
of 29 ± 16
months,
with
over
95%
showing symptoms
of
speech loss, social
disturbances, stereotyped behaviors, resistance
to
change,
anxiety
and
deterioration
of
self-help skills (Volkmar,
1992, 1994).
In
children with autism,
it is
also well recognized
that
clinical regression
can and
often
does occur
as
early
as 15
months
of
age, with
a
mean
age of 21
months
(Tuchman,
1996).
The
relationship between autism with
an
early regressive course (before
36
months),
CDD
(after
36
months),
Landau-Kleffner
syndrome (Landau
&
Kleffner,
1957; Landau
&
Kleffner,
1998),
and
elec-
trical status epilepticus during slow wave sleep (ESES)
is
currently poorly understood,
as is the
underlying eti-
ology
and
pathophysiology (Bristol
et
al., 1996; Tuch-
man
&
Rapin, 1997). Estimates
of the
rates
of
regres-
sion
in
children with autism range
from
10 to
over
50%
(Hoshino
et
al., 1987; Tuchman
&
Rapin, 1997), with

448
Filipek
et al.
total loss
of
expressive language occurring
in
between
20 and 40%
(Kurita, 1985,1996; Kurita, Kita,
&
Miyake,
1992; Rutter
&
Lord, 1987). Between
36 and 55% of
parents
of
children with autism note problems
in the
first
year
of
life,
but
likely only retrospectively (Short
&
Schopler, 1988; Volkmar, Stier,
&
Cohen, 1985). Some
children
had
autistic symptoms quite early,
but did not
receive
a
medical referral
or
assessment
until
2 or 3
years
of
age. Either parents failed
to
recognize
the
insidious
problems
or the
physician
or
others discounted
the
parental concerns. Acute
or
subacute
loss
of
language
is
more likely
to
motivate parents
to
seek medical help than
is
the
onset
of
social abnormalities (Rogers
&
DiLalla,
1990).
One of the
most
troubling
problems
hindering
a
better understanding
of
autistic regression
and CDD in-
volves
the
disentangling
of
"age
at
onset"
from
"age
at
recognition" (Volkmar
et
al., 1985). Retrospective eval-
uation
of
home movies
and
videotapes
is now a
well-
accepted research strategy
for
identifying autistic symp-
toms
by as
early
as 12
months
of age
(Adrien
et
al., 1992;
Baranek, 1999; Osterling
&
Dawson, 1994).
Autism with regression
and CDD
have both been
associated with seizures
or
epileptiform electroencepha-
lograms (EEG) (Rapin, 1997; Tuchman, 1995; Tuchman
&
Rapin, 1997; Tuchman, Rapin,
&
Shinnar, 1991a,
1991b).
In a
recent study
of
children with autism
with
a
history
of
regression (Tuchman
&
Rapin, 1997), there
were almost twice
as
many children
in the
sample
with
epileptiform EEGs (21%)
as
there were with clinical
epilepsy (11%), which indexes
a
significant
portion
of
children with autism
with
subclinical epileptiform
ac-
tivity. These investigators suggested that regression
has
a
significant association with
an
epileptiform EEG, even
in
the
face
of a
lack
of
clinical seizure activity (19%
in
those with regression
vs. 10% in
those without).
The ma-
jority
of the
epileptiform EEGs were localized
to the
centrotemporal regions.
It is
noteworthy that seizures
or
epileptiform EEGs were more prevalent
in
those chil-
dren with regression
who
also
demonstrated
a
significant
cognitive deficit (Tuchman
&
Rapin, 1997).
Atypical
Autism/
PDD Not
Otherwise
Specified (PDD-NOS)
These diagnoses
are
used when clinically
signifi-
cant autistic symptomatology
is
present, including
deficits
in
reciprocal social interactions, verbal
or
non-
verbal communication,
or
stereotyped behavior, inter-
ests,
and
activities,
but
full
criteria
are not met for an al-
ternative specific diagnosis under
the
autistic spectrum
or PDD
umbrella;
for
example,
in a
child
who
does
not
meet
the
required total
of 6 of the
possible
12
criteria
for
the
diagnosis
of
Autistic Disorder,
or who had
symp-
tom
onset
after
age 36
months. Also, children whose
symptoms
are
atypical
or not as
severe would
be
coded
under this diagnosis (APA, 1994).
Atypical
autism/ PDDNOS
is not a
distinct clinical
entity
with
a
specific definition, although individuals
given
this diagnosis
are
traditionally thought
to
have
milder symptoms. PDDNOS
is a
diagnosis
by
exclusion
of
the
other autistic spectrum disorders (Towbin, 1997).
It
is
often
used
as a
"default"
or
"wastebasket" diagno-
sis
when either
insufficient
or
unreliable information
is
available,
or
when
the
practitioner
is
hesitant
to use the
term "autism." Indeed, when
176
children diagnosed
by
DSM-III-R
criteria
(APA, 1987) with
Autistic
Disorder
were compared with
18
children diagnosed with
PDDNOS,
no
significant
differences
were noted
on any
neuropsychological
or
behavioral measures when
co-
varied
for
nonverbal
IQ
(Rapin
et
al.,
1996).
Screening
and
diagnostic procedures
for
atypical autism/PDDNOS
is the
same
as for the
other autistic spectrum disorders,
as
is
management.
Rett Syndrome
Rett
syndrome,
a
neurodegenerative disorder
es-
sentially
limited
to
girls, becomes manifest
after
a pe-
riod
of
normal
function
after
birth. Although
it was
first
described
by
Rett
in
1966, clinical awareness
of the
syn-
drome
did not
occur
until
Hagberg
et al.
(1983) reported
35
additional cases.
The
girl with Rett syndrome initially
presents
as
early
as age 6 to 8
months,
after
a
normal
birth,
a
normal newborn head circumference,
and
nor-
mal
early developmental milestones, with
a
decelerating
head
circumference growth rate. This
is
eventually fol-
lowed
by
microcephaly
(i.e.,
head circumference
less
than
the
second percentile)
and by the
loss
of
purpose-
ful
hand skills. Subsequently, stereotypic hand move-
ments such
as
wringing, washing, licking,
or
clapping,
and
poor truncal
or
gait coordination develop, with loss
of
social engagement
and
severely impaired receptive
and
expressive language development
and
cognitive
skills (Armstrong, 1997; Hagberg
et
al., 1983; Naidu,
1997; Percy, Gillberg, Hagberg,
&
Witt-Engerstrom,
1990). Almost
all the
children have abnormal EEGs with
slow
background activity
and
spikes,
but
clinical seizures
occur
in
only about
one
third
of
cases (Armstrong, 1997;
Naidu,
1997; Percy
et
al., 1990). There
is
general agree-
ment
that Rett syndrome
is a
developmental disorder,
al-
though
its
classification
in
DSM-IV
and
ICD-10
as a
PDD
remains controversial (Burd, Fisher,
&
Kerbeshian,
1989; Gillberg, 1994; Tsai, 1992). However,
it was
clas-
sified
under
the PDD
umbrella
so
that
a
misdiagnosis
of

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
449
autism would
not be
given
in
lieu
of the
correct diag-
nosis
of
Rett syndrome.
SCREENING
AND
DIAGNOSIS
OF
AUTISM:
"SCREEN,
PROBE, EVALUATE"
Screening
for
autism calls
for two
different
levels
of
investigation, each answering
a
different
question
(Siegel, 1998). Level
1
screening should
be
performed
on
all
children
and
involves identifying children
at
risk
for
any
type
of
atypical development. Level
2
involves
a
more in-depth investigation
of
children already iden-
tified
to be at
risk
for a
developmental
disorder,
differ-
entiates autism
from
other kinds
of
developmental dif-
ficulties,
and
includes evaluations
by
autism specialists
aimed
at
determining
the
best means
of
intervention
based
on the
child's
profile
of
strengths
and
weaknesses.
Please
refer
to the
Algorithm (Fig.
1) for an
overview
of
this process. Although
the
process itself
has
been sepa-
rated into
two
levels
of
evaluation, this
does
not
neces-
sarily indicate separate independent levels
of
profes-
Fig.
1.
Algorithm.
sional
involvement,
as a
given single professional
may
well perform both sequential stages.
Since
we
currently have
no
biological marker
for
autism, screening must focus
on
behavior. Furthermore,
in
most
cases,
autism appears
to
have
a
gradual onset,
often
without
clear
evidence
of
sensorimotor impair-
ment.
Children with autism typically sit, crawl,
and
walk
at the
expected age. Many even produce
a few
words
at
developmentally appropriate times, although
these words seldom develop into
useful
early language.
Symptoms that
may be
present during infancy
(a
seri-
ous
expression, increased irritability, sleep
and
eating
difficulties,
and
placidity)
are
behaviors commonly
seen
in
otherwise typically developing children.
At
the
present time, specific behaviors that distin-
guish
infants
with autism
from
others
at 12
months
of
age
have been identified
in
studies using observations
based
on
home videotapes (Osterling
&
Dawson,
1994).
Using
home videotapes
of
first
birthday parties
in
infants
with
autism versus typical development, these investi-
gators
found
that
four
behaviors correctly identified over
90% of the
autistic
and
typical infants. These behaviors,
which
were replicated
in a
subsequent study (Mars,
Mauk,
&
Dowrick, 1998), were
eye
contact, orienting
to
name being called, pointing,
and
showing.
A
more recent
study
of
home videotapes
of
first
birthdays (Osterling
&
Dawson,
1999)
found
that these 1-year-olds with autism
could
also
be
distinguished
from
1-year-olds with idio-
pathic mental retardation. One-year-old
infants
with
autism
used
less
eye
contact
and
oriented
to
their names
less
frequently
than those with mental retardation
and
those with typical development. Furthermore, these same
behaviors distinguished these same
infants
with autism
at 8 to 10
months
from
those
with
typical development
(Brown,
Dawson, Osterling,
&
Dinno, 1998). Baranek
(1999) similarly used retrospective video analysis with
9- to
12-month-old
infants
and
found
that
a
pattern
of
nine
behaviors differentiated between autism, develop-
mental disabilities
and
typical development with
94% ac-
curacy.
The
autistic pattern included
greater
problems
with
responsiveness
to
social
stimuli
(e.g.,
delayed
re-
sponding
to
name;
social
touch aversion)
as
well
as
other
nonsocial
aspects
of
sensory responsiveness. Although
the
long-range stability
and
predictive utility
of
these
findings
remains
to be
determined,
these
results suggest
that autism will eventually
be
reliably
detected
as
early
as 1
year
of
age,
or
even younger (Baranek, 1999; Teit-
elbaum, Teitelbaum, Nye, Fryman,
&
Maurer, 1998).
Autism
can be
diagnosed reliably
in
children
by
or
before
the age of 3
years. Recent studies have demon-
strated
that symptoms
of
autism
are
measurable
by
18
months
of
age,
and
that these symptoms
are
stable

450
Filipek
et al.
from
toddler
age
through
the
preschool
age
(Charman
et
al., 1997;
Cox et
al., 1999; Lord, 1995; Stone
et
al.,
1999). Furthermore, these studies have identified
the
main
characteristics
that differentiate autism from
other
de-
velopmental disorders
in the
20-month
to
36-month
age
range, characteristics that early screening
tools
need
to
target. These involve negative symptoms,
or
behavioral
deficits,
in the
following areas:
eye
contact, orienting
to
one's
name, joint attention behaviors (e.g., pointing,
showing),
pretend play, imitation, nonverbal communi-
cation,
and
language development. There
is
some indi-
cation that socially directed emotional behavior
may
also
differentiate
the
groups; neither sensory-perceptual
nor
positive symptoms such
as
repetitive behaviors
or be-
havioral outbursts appear
to
consistently differentiate
between autistic
and
nonautistic groups early
on.
Screening
for
autism
may not
identify
children with
milder variants
of the
disorder (without mental retarda-
tion
or
obvious language delay). These children's
diffi-
culties
often
go
undiagnosed
for
years, causing them
in-
creasing
difficulty
as
they
try to
meet
the
demands
of
elementary education without needed supports. Their dif-
ficulties
cause great stress
for
their families,
who
recog-
nize
the
child's
challenges
but
have
difficulty
convinc-
ing
others that their child
has a
disability.
These
children
and
their families will benefit greatly
from
improved
screening
efforts
and the
increased opportunity
for ef-
fective
intervention that screening activities
can
yield.
However, this screening also needs
to
target
the
symp-
toms
of
verbal individuals with high-functioning autism
and
Asperger disorder,
and
must focus
on
older children,
adolescents,
and
young adults (Garnett
&
Attwood,
1998). Such screens
are
also relevant
for
educational set-
tings,
where
these
older children
may
also
be
recognized.
Level
1:
Routine Developmental Surveillance
and
Screening
Specifically
for
Autism
It is the
consensus
of
this Panel that primary care
providers must change their approach
to
well-child care,
so as to
perform proactive screening
for
developmental
disorders.
It has
been estimated that almost
25% of
chil-
dren
in any
practice demonstrate developmental issues
at
some
point. Therefore,
developmental
screening
must
become
an
absolutely essential routine
of
each
and
every
well-child visit throughout infancy, toddler,
and
pre-
school years,
and
even beyond early school-age
if
con-
cerns
are
raised.
The
additional
use of
Specific Devel-
opmental Probes will increase
the
sensitivity
and
specificity
of the
screening process
for
autism.
Unfortunately,
fewer than
30% of
primary care
providers conduct standardized screening tests
(in the
rigid manner
for
which they were intended)
at
well-
child appointments (Dworkin, 1989, 1992; Majnemer
&
Rosenblatt, 1994; Rapin, 1995). Additionally,
the
Amer-
ican
Academy
of
Pediatrics
(AAP)
is
stressing
the im-
portance
of
developmental surveillance
at
every well-
child
visit:
a
flexible, continuous process that
is
broader
than
screening
and
includes eliciting
and
valuing parental
concerns, specific probing regarding age-appropriate
skills
in
each developmental domain,
and
skilled obser-
vations
(American Academy
of
Pediatrics Committee
on
Children
with Disabilities, 1994; Johnson
&
Blasco,
1997). Implementation
of the
developmental surveillance
process
at
every well-child visit
and the
acquisition
of
the
necessary skills
to
make
it
happen will only
be
accomplished with training
at the
preservice
and in-
service levels. Additionally, current managed-care pol-
icy,
which allows only
a few
minutes
for
well-child
ap-
pointments, must change
if
clinicians
are to
implement
the
training they receive (Glascoe, Foster,
&
Wolraich,
1997).
A
high degree
of
advocacy
on the
part
of
parents,
health care professionals,
and
managed
care
adminis-
trators
is
essential
if the
recommendations
of
this Prac-
tice Parameter
are to be
appropriately implemented.
It is
important
to
realize
that
parents
usually
are
cor-
rect
in
their concerns about their child's development
(Glascoe, 1994, 1997, 1998; Glascoe
&
Dworkin, 1995).
They
may not be as
accurate regarding
the
qualitative
and
quantitative
parameters surrounding
the
developmental
abnormality,
but
almost always,
if
there
is a
concern,
there
is
indeed
a
problem
in
some aspect
of the
child's
development.
Any
developmental concern
on
Chief Com-
plaint
must
be
valued
and
lead
to
further
investigation.
Although
a
positive parental concern strongly sug-
gests
an
underlying developmental problem,
the
lack
of
concern does
not
imply normal development. Lack
of
parenting experience, cultural influences, denial,
time
constraints
in the
presence
of
more pressing med-
ical issues,
all
contribute
to
parental reluctance
to
bring
up
developmental issues. Even when
the
parents
ex-
press
no
concerns,
a
child's development should
be
monitored
closely
by
using
one of the
available parental
questionnaire instruments. Some clinics utilize well-
child clinic
forms
with preprinted developmental mile-
stones
that
are
appropriate
for
each
routine
visit.
The
information
on
these
forms
should
be
taken
from
valid
milestone charts
and
cover each developmental domain.
General Developmental Screening: Parental
Questionnaires
Traditional
Instruments.
The
Denver-II (DDST-II,
formerly
the
Denver
Developmental Screening Test-

Screening
and
Diagnosis
of
Autistic Spectrum
Disorders
451
Revised; Frankenburg, Dodds, Archer, Shapiro,
&
Bres-
nick, 1992)
has
been
the
traditional
tool
used
for
devel-
opmental screening
in
primary
care
practices.
It is de-
signed
for
children from birth
to 6
years
of
age,
and
samples receptive
and
expressive language, articulation,
fine
motor-adaptive,
personal-social,
and
gross
motor
skills.
It
yields
a
single score (abnormal, questionable,
untestable, normal,
or
advanced). Easy
to
administer
and
score,
the
test
can be
completed
in 25
minutes
or
less.
However,
the
validity
of the
test
has not
been studied.
In
addition, subsequent research
found
that
the
measure
was
significantly
insensitive (meaning that
the
instrument
missed
a
significant number
of
delayed children—many
missed
true
positives)
and
lacked
specificity (meaning
that
a
significant number
of
normal children—true neg-
atives—were misclassified
as
delayed) (Glascoe
et
al.,
1992).
The
Revised Denver Pre-Screening Developmen-
tal
Questionnaire (R-DPDQ; Frankenburg, 1986),
in
con-
trast,
is
designed
to
identify
a
subset
of
children
who
need
further
screening.
It
uses parental report
and
pres-
ents
10 to 15
items, sampling
the
various domains,
in the
age
range
of
birth
to 6
years.
R-DPDQ
items
were
drawn
from
the
Denver Developmental Screening Test (the very
popular
predecessor
of the
Denver-II) which detected
only
30% of
children with language impairments
and
50% of
children with mental retardation (Borowitz
&
Glascoe, 1986; Glascoe
et
al., 1992; Greer, Bauchner,
&
Zuckerman, 1989). Many other comprehensive studies
also
document
the
lack
of
sensitivity
and
specificity
of
this
instrument
(Cadman
et
al., 1984; Camp,
van
Doorn-
inck, Frankenburg,
&
Lampe, 1977; Diamond, 1987;
Grant
&
Gittelsohn, 1972; Harper
&
Wacker, 1983;
Lindquist, 1982; Sciarillo, Brown, Robinson, Bennett,
&
Sells,
1986; Sturner, Green,
&
Funk, 1985). Because
of
the
lack
of
sensitivity
and
specificity
of
both
the
DDST-II
and
R-DPDQ,
an
alternative instrument must
be
used
for
appropriate Level
1
primary-care screening
at
every
well-child
visit.
Standardized
Developmental
Screening
Instru-
ments. Examples
of
Level
1
parent questionnaires
with
acceptable psychometric properties include:
(a) The
Ages
and
Stages Questionnaire, Second Edition (ASQ; Bricker
&
Squires, 1994; Bricker
&
Squires, 1999; Squires,
Bricker,
&
Potter, 1997) uses parental report
for
children
from
birth
to 3
years,
and
provides
clear
drawings
and
directions
for
eliciting
thoughtful
responses.
Separate
forms
of 10 to 15
items
for
each
age
range
are
tied
to
the
well-child visit schedule. Modifications
are
available
for
screening children
at
other particular ages. Well-
standardized
and
validated,
the ASQ has
good sensitiv-
ity
and
excellent specificity
and
provides
pass-fail
scores.
Because
it is
difficult
to use the
single outcome score
to
make referrals
and
because
of the
ASQ's brevity,
it ap-
pears especially
useful
as a
prescreening tool.
(b) The
BRIGANCE® Screens (Brigance, 1986; Glascoe, 1996)
consist
of
seven separate forms,
one for
each 12-month
age
range
from
21 to 90
months
of
age.
It
taps
key de-
velopmental
and
early
academic
skills,
including
speech-
language,
fine
and
gross motor, graphomotor develop-
ment,
and
general knowledge
at
younger ages
and
also
reading
and
math
at
older
ages.
It
uses direct elicitation
and
observation,
and
takes
in
approximately
10
minutes
to
administer.
It is
available
in
English
or
Spanish.
It
is
well standardized
and
validated,
and has
been
in use
for
over
10
years.
The
Screens produce
cutoff
and
age-
equivalent
scores
for
motor, language,
and
readiness,
and
an
overall
cutoff
score.
The
Screens also have good sen-
sitivity
and
specificity
to
giftedness.
(c) The
Child
De-
velopment
Inventories
(CDIs; Ireton, 1992; Ireton
&
Glascoe, 1995) include three separate measures
with
60
items each (the
Infant
Development Inventory, birth
to 21
months
of
age; Early Child Development Inven-
tory,
15 to 36
months
of
age;
and the
Preschool Devel-
opment Inventory,
36 to 72
months
of
age).
All are
com-
pleted
by
parental report
in
about
5 to 10
minutes.
The
CDIs
can be
self-administered
in
waiting
or
exam rooms
or
mailed
to
families.
For
parents
with
limited English,
items
can be
directly administered
to
children.
The
CDIs
screen
for
language, motor, cognitive, preacademic,
social, self-help, behavior,
and
health problems. Forms
for
the
older
two age
groups produce
a
single
cutoff
score
equivalent
to 1.5
standard
deviations
below
the
popula-
tion mean. Clinicians must then analyze
errors
to
deter-
mine
the
domains
in
which children
are
having
the
most
difficulty
in
order
to
make appropriate referrals (e.g.,
fine
motor deficits might dictate
an
occupational ther-
apy
referral whereas global deficits dictate
the
need
for
comprehensive assessment). Although
the
CDIs
were standardized exclusively
in St.
Paul,
MN, a
num-
ber of
validity
studies
support
the
instruments' effec-
tiveness
in
other geographic locations,
with
minorities
and
with
groups with lower socioeconomic status (Chaf-
fee,
Cunningham, Secord-Gilbat, Elbard,
&
Richards,
1990; Guerin
&
Gottfried, 1987; Ireton
&
Glascoe, 1995;
Sturner,
Funk, Thomas,
&
Green,
1982).
These
also
showed
the
measures
to
have excellent sensitivity
and
good specificity.
The
parent instrument
to the
CDIs,
the
Child
Development Inventory,
is
more
of an
assessment
than
a
screening tool
for
children
15 to 72
months
of
age.
(d)
The
Parents'
Evaluation
of
Developmental Status
(PEDS, Glascoe, 1998) helps providers
carefully
elicit
and
interpret parents' concerns. PEDS assigns probabil-
ities
of
delays
and
disabilities
to the
various types
of
con-
cerns, thus enabling clinicians
to
make evidence-based

452
Filipek
et al.
decisions, provide
in-office
counseling, encourage sug-
gestions,
and
give reassurance.
To use
PEDS, parents
must
answer
10
questions. These
are
written
at the
fifth-
grade
level
in
English
and in
Spanish,
and
more
than
90%
of
parents
can
complete
the
questionnaire
in
writing
while
they wait
for
their appointment. Clinicians
or of-
fice
staff
can
score
and
interpret
the
results
in
about
2
minutes. PEDS
was
validated
and
standardized
on 971
children around
the
country
in
four
separate validation
studies (Glascoe, 1991, 1994; Glascoe, Altemeier,
&
MacLean, 1989; Glascoe, MacLean,
&
Stone, 1991).
Its
accuracy
in the
detection
of
disabilities meets conven-
tional standards
for
screening tests (sensitivity
to
devel-
opmental problems
and
specificity
to
normal develop-
ment
of 70 to
80%). Research
on
PEDS shows that
parents
are
likely
to be
accurate, regardless
of
their level
of
education
or
parenting experience.
Chief
Complaints
and
Specific
Probes Regarding
Developmental Concerns
There
are at
least three general concerns
with
which
young children
and
their parents present
to the
primary
care
provider
at a
well-child
visit:
speech
or
language delay; problems with social development with
or
without similar concerns
in
speech
or
language;
and
the
development
of a
younger sibling
of a
child with
known
or
suspected autism.
Any
child whose parents
are
concerned
in
these
areas
should
be
further
evalu-
ated through Levels
1 and 2, as
appropriate.
Any
con-
cern that implies
"regression"
or
loss
of
skills
in
lan-
guage
or
social
skills should
be a
serious
red
flag.
The
Child Whose Parents
Are
Concerned
about
Speech
or
Language Delay. Chief complaints about "iso-
lated"
speech deficits
are the
most common concerns
raised
by
parents
in
children between
the
ages
of 1 and
5
years. Most
of the
time these concerns relate
to
delayed
expressive language, because parents
are not
usually
as
knowledgeable about their child's
receptive
language
skills.
There
are
several classic parental concerns,
as
well
as
absolute language milestone misses, either
of
which
should
immediately prompt
further
investigation (Table
III). When these
or
other language concerns
are
voiced,
the
Level
1
provider
should
probe
with
questions
to the
parent
regarding social skills
and
behavior,
as
well
as
communication,
in an
effort
to
determine whether there
are any
problems
in
addition
to
language (Table IV).
The
Child with
a
Suspected Problem
in
Social
De-
velopment
or
Behavior (with
or
without Similar Con-
cerns
in
Speech
or
Language).
Any
concerns regarding
problems with
social
development should always
be
taken seriously,
as
seriously
as an
older child's com-
Table
III. Parental Concerns that
are RED
FLAGS
for
Autism
Communication
Concerns
Does
not
respond
to
his/her name
Cannot
tell
me
what (s)he wants
Language
is
delayed
Doesn't
follow directions
Appears deaf
at
times
Seems
to
hear sometimes
but not
others
Doesn't point
or
wave bye-bye
Used
to say a few
words,
but now he
doesn't
Social Concerns
Doesn't smile socially
Seems
to
prefer
to
play alone
Gets
things
for
himself
Is
very independent
Does
things
"early"
Has
poor
eye
contact
Is
in his own
world
Tunes
us out
Is
not
interested
in
other children
Behavioral
Concerns
Tantrums
Is
hyperactive/uncooperative
or
oppositional
Doesn't know
how to
play with toys
Gets
stuck
on
things over
and
over
Toe
walks
Has
unusual
attachments
to
toys (e.g., always
is
holding
a
certain object)
Lines things
up
Is
oversensitive
to
certain textures
or
sounds
Has odd
movement patterns
Absolute
indications
for
immediate
further
evaluation
No
babbling
by 12
months
No
gesturing (pointing,
waving
bye-bye, etc)
by 12
months
No
single words
by 16
months
No
2-
word spontaneous (not
just
echolalic) phrases
by
24
months
ANY
Loss
of ANY
Language
or
Social
Skills
at ANY Age
plaint
of
back
or
chest pain. Unlike
"stomachaches"
and
"headaches"
which
are
common, self-limiting,
and can
often
be
treated symptomatically without
a
diagnostic
workup,
a
complaint
of
back
or
chest pain
is
rare
and
deserves investigation. Similarly, parents rarely com-
plain
of
social delays
or
problems,
so any and all
such
concerns should
be
immediately investigated.
In
addi-
tion,
complaints
about
behavioral
concerns
that
coexist
with
any
other concerns
of
social
or
communication
de-
velopment
should
be
immediately investigated (see
Ta-
bles
III and
IV).
It is
even more significant when par-
ents voice additional concerns
in the
communication
and
behavior areas
as
well
as in
socialization.
The
Younger
Sibling
of an
Older Child
with
Known
or
Suspected
Autism.
The
younger sibling(s)
of
an
autistic child deserves special attention whether
or

Screening
and
Diagnosis
of
Autistic Spectrum
Disorders
453
Table
IV, Ask
Specific Development Probes:
"Does
(s)he
. . ." or "Is
there
. . ."
Socialization
. . .
cuddle like other children?
. . .
look
at you
when
you are
talking
or
playing?
. . .
smile
in
response
to a
smile
from
others?
. . .
engage
in
reciprocal,
back-and-forth
play?
. . .
play simple imitation games,
such
as
pat-a-cake
or
peek-a-boo?
. . .
show interest
in
other children?
Communication
. . .
point with
his finger?
. . .
gesture?
nod yes and no?
. . .
direct your attention
by
holding
up
objects
for you to
see?
.
. .
anything
odd
about
his/her
speech?
. . .
show things
to
people?
. . .
lead
an
adult
by the
hand?
. . .
give inconsistent responses
to
name?
. . . to
commands?
. . . use
rote,
repetitive,
or
echolalic speech?
. . .
memorize strings
of
words
or
scripts?
Behavior
. . .
have repetitive, stereotyped,
or odd
motor behavior?
. . .
have preoccupations
or a
narrow range
of
interests?
. . .
attend more
to
parts
of
objects (e.g., wheels)?
. . .
have limited
or
absent pretend play?
. . .
imitate other
people's
actions?
. . .
play with toys
in the
same exact
way
each time?
. . .
strongly attached
to a
specific
unusual
objects(s)?
not
the
parents have concerns about this
child's
de-
velopment. Siblings constitute
an
important autism-risk
group; their development needs
to be
monitored very
carefully
not
only
for
autism-related symptoms
but
also
for
language delays
and
early anxiety symptoms. While
some parents
may be
overly vigilant regarding
the
pres-
ence
of
"autistic features"
and
overreact, other parents
may
not
realize
that their younger child demonstrates
milder autistic symptoms,
because
the
severity
of the
older child overshadows
the
subtle abnormalities
in the
younger.
The
main advantage
of
identifying young
children with autism
as
soon
as
possible
is to
provide
them with early treatment
in
high quality autism inter-
vention programs. Additionally,
it is
important
to
note
that
a
younger sibling
may
mimic their older autistic
sibling even when s/he
has no
innate autistic charac-
teristics
of
her/his own. When
the
parents
do
have
a
concern, Level
1
screening should
proceed
directly
to
the
autism-specific questionnaires. When
the
parents
have
no
concerns, screening should both probe
for
autistic behaviors
and
monitor
all
developmental
do-
mains
at
each
and
every well-child visit. Because there
are no
pathognomonic signs
or
diagnostic tests
for
autism,
the
history
is one of the
most important tools
used
to
determine whether
or not the
child
is at
risk
for
a
diagnosis
of
autism. Level
1
professionals must
learn what questions
to ask and how to
interpret
the
answers
in the
context
of
normal child development
(see Tables
HI and
IV).
Level
1
Laboratory
Investigations
Formal Audiologic Evaluation
All
children with developmental delays, especially
those
with
delays
in
social
and
language development,
should
undergo
a
formal audiologic hearing evaluation.
This
may
become
a
moot point
as the
standard
of pe-
diatric
care
moves
toward
universal
screening.
Until
such
time,
any
child with delayed language
or at
risk
for
autism should
be
provided with
a
referral
for
audiologic testing
on the
same
day
that
a
concern
is
identified.
Parent
or
practitioner concern regarding
a
speech,
language,
or
hearing problem (loss
of
sensitivity, incon-
sistent responses,
no
response,
or
unusual responses
to
sounds
or
sound sources) should result
in an
immediate
referral
for
audiologic assessment. Comprehensive hear-
ing
tests should
be
provided
by an
audiologist with
ex-
perience
in the
assessment
of
very young children
and
difficult-to-test
populations. This referral should occur
regardless
of the
child
having
"passed"
a
neonatal hear-
ing
screen. Integrity
of
hearing cannot
be
determined
by
informal
observations
of
behavioral responses
to
envi-
ronmental
sounds
or by
parent-caregiver report. Hearing
loss (conductive, sensorineural,
or
mixed)
can
co-occur
with
autism; children with autism
may be
incorrectly
thought
to
have peripheral hearing
loss
(Adkins
&
Ainsa,
1979; Jure, Rapin,
&
Tuchman, 1991; Klin, 1993; Smith,
Miller, Stewart, Walter,
&
McConnell,
1988).
Audiologic
assessment should occur early
in the
differential diag-
nostic
process
and
include
a
battery
of
tests
including
be-
havioral audiometric measures, assessment
of
middle-ear
function
and
electrophysiologic procedures (American
Speech-Language-Hearing Association,
1991).
The
goal
of
audiologic assessment
is to
delineate
the
type,
degree,
configuration,
and
symmetry
of any
existing
hearing
loss
or to
confirm
the
presence
of
nor-
mal
peripheral hearing sensitivity.
Two
broad
categories
of
hearing assessment methods
are
available: behavioral
and
electrophysiologic.
Behavioral audiologic assess-
ment
should include measures
of
hearing that
are ap-
propriate
for the
child's developmental
level.
Uncon-
ditioned behavioral response procedures (behavioral
observation audiometry
or
BOA)
are of
limited
use in
characterizing hearing sensitivity
as a
function
of
fre-
quency.
Conditioned response procedures (such
as

454
Filipek
et al.
Visual
Reinforcement Audiometry
or
Conditioned Play
Audiometry)
are
useful
in
audiologic assessment
of
chil-
dren beginning
at the
developmental
age of 6
months.
Reliable, accurate, frequency-specific threshold infor-
mation
may be
obtained using this simple, pleasant,
and
cost-effective
method.
The
audiologic assessment
of
chil-
dren
with autism
may
present challenges
for the
audiol-
ogist requiring modifications
of
traditional test tech-
niques
and
test
environments. Limited reports
and
clinical experience suggest that many children with
autism
may be
assessed using operant test procedures
(Gravel, Kurtzberg, Stapells, Vaughan,
&
Wallace, 1989;
Verpoorten
&
Emmen, 1995).
Electrophysiologic procedures
are
useful
for
esti-
mating
hearing sensitivity
and for
examining middle ear,
cochlear,
and
VII3Ith nerve
or
auditory brainstem path-
way
integrity (Gorga, Kaminski, Beauchaine, Jesteadt,
&
Neely, 1989; Stapells, Gravel,
&
Martin, 1995).
These
methods require
no
behavioral
response
from
the
child,
although
a
child must
be
quiet (usually,
in
natural
or se-
dated sleep)
for
varying amounts
of
time depending upon
the
procedure. Acoustic immittance procedures, specif-
ically tympanometry,
are
useful
for
quantifying
middle-
ear
function,
and
acoustic reflex threshold assessment
can be
used
as a
cross-check
of
auditory
function.
Evoked
otoacoustic emissions
are
useful
for
examining cochlear
(sensory)
function.
This measure
is
frequency-specific,
and
time-
and
cost-efficient. Evoked otoacoustic emis-
sions
are
absent with hearing
losses
greater
than
30 to
40 dB
(Prieve, 1992; Robinette, 1992)
and the
technique
has
been used
in
children with autism (Grewe, Danhauer,
Danhauer,
&
Thornton, 1994).
The
frequency-specific
Auditory
Brainstem Response (ABR)
is the
single most
useful
electrophysiologic procedure
for use in
estimat-
ing
hearing thresholds
and has
been demonstrated
to be
highly
correlated with behavioral hearing thresholds
in
children
who
hear normally
and in
children
who
have
sensorineural hearing loss (Stapells
et
al., 1995).
Audiologic assessment should
not be
delayed
in
the
differential diagnosis
of
autism.
It is
recommended
that
audiologic assessment
be
completed
at
centers that
have qualified
and
experienced professional personnel
(pediatric audiologists)
who
have current test methods
and
technologies readily available.
It is
recommended
that
facilities without these components enter con-
sortial arrangements with centers that
are
able
to
pro-
vide this type
of
comprehensive assessment
of
children
with
autism.
When
hearing loss (conductive
or
sensorineural)
is
detected,
the
child should
be
referred
to an
otolaryngol-
ogist,
but
concerns raised
at the
Level
1
screen regard-
ing
other developmental indicators ('red flags")
for
autism
(e.g., lack
of
social relationships, unusual
be-
haviors)
must
not be
ignored.
The
audiologist,
speech-
language pathologist,
and
medical practitioner's follow-
up
of the
child should include surveillance
for
indicators
of
autism. When appropriate, in-depth assessment (psy-
chological, sensorimotor) should
be
recommended
in
order
to
address
the
potential co-occurrence
of
autism
and
hearing loss.
Transient,
fluctuant
conductive hearing
loss
asso-
ciated
with otitis media with
effusion
can
co-occur
in
children
with
autism. Audiologic
and
medical follow-
up
for
conductive hearing
loss
associated with recur-
rent
otitis media
is
important
in the
long-term man-
agement
of
children with autism.
Lead Screening
Children with developmental delays
who
spend
an
extended
period
in the
oral-motor
stage
of
play (where
everything
"goes
into their mouths")
are at
increased risk
for
lead toxicity especially
in
certain environments.
The
prevalence
of
pica
in
this group
can
result
in
high rates
of
substantial
and
often
recurrent exposure
to
lead and,
quite
possibly, other metals (Shannon
&
Graef, 1997).
Several studies report
the
neurobehavioral
effects
and
behavioral toxicity
of
lead
and its
potential clinical rel-
evance
in
patients with autism. Mean blood lead con-
centration
was
notably higher
in 18
children
with
autism
than
in 16
nonautistic children
or in 10
normal siblings;
44% of the
autistic
and
psychotic children
had
blood lead
levels greater than
2
standard deviations above
the
mean
for
normal controls (Cohen, Johnson,
&
Caparulo,
1976).
In
three
of six
reported
cases
of
lead poisoning
in
chil-
dren with autism, developmental deviance
seemed
to
have been present before
the
possible impact
of
lead tox-
icity, while
in
two,
the
lead poisoning
may
have con-
tributed
to the
onset
or
acceleration
of
developmental
symptomatology
(Accardo, Whitman, Caul,
&
Rolfe,
1988).
A
more recent chart review
found
that
17
chil-
dren with autism were treated
for
plumbism over
a
6-year period
from
1987
to
1992. When compared
to a
randomly
selected group
of 30
children without autism
who
were treated during
the
same interval,
the
children
with
autism were significantly
older
at
diagnosis,
had a
longer period
of
elevated blood lead levels during treat-
ment,
and 75%
were subsequently
reexposed
despite
close
monitoring, environmental inspection,
and
either
lead hazard reduction
or
alternative housing (Shannon
&
Graef,
1997).
Therefore,
all
children with delays
or who
are at
risk
for
autism should have
a
periodic lead screen
until
the
pica disappears (Centers
for
Disease Control
and
Prevention, 1997; Shannon
&
Graef, 1997).

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
455
Specific
Screening
for
Autism
All
professionals involved
in
early child care (pe-
diatricians,
neurologists,
psychiatrists,
psychologists,
audiologists, language pathologists, occupational thera-
pists,
and
physical therapists) should
be
sufficiently
familiar
with
the
signs
and
symptoms
of
autism
to
rec-
ognize possible indicators (social, communicative,
and
behavioral)
of the
need
for
further
diagnostic evaluation.
It
is
important
to be
aware that children
with
autism
often
are
referred
for a
variety
of
concerns, such
as
language
delays, regulatory behavior problems
in
infancy,
motor
or
sensory problems, social
and
behavioral problems,
emotional disturbance,
and
learning problems.
There
are new
screening instruments
in the field
that
focus
on
children
with
autism:
the
Checklist
for
Autism
in
Toddlers (CHAT; Baron-Cohen, Allen,
&
Gillberg,
1992; Baron-Cohen
et
al., 1996),
the
Pervasive Devel-
opmental Disorders Screening Test (PDDST., Siegel,
1998),
and for
undiagnosed older verbal children,
the
Australian
Scale
for
Asperger's Syndrome (Garnett
&
Attwood, 1998).
Checklist
for
Autism
in
Toddlers (CHAT; Baron-
Cohen
et
al., 1992; 1996)
is
designed
to
screen
for
autism
at 18
months
of
age,
and is
also aimed
at the
pri-
mary care setting.
The
first
section consists
of a
series
of
nine questions
to be
asked
of the
parent, such
as
whether
the
child ever demonstrates
any
pretend play.
The
second section consists
of a
series
of
five
items
to
be
observed
or
administered
to the
child
by the
provider
during
the
visit, such
as
seeing whether
the
child looks
where
you
point (joint attention),
has any
interest
in
pre-
tend play,
or is
able
to
follow
a
command. Strengths
of
the
CHAT include
its
ease
of
administration
and its
demonstrated specificity
to
symptoms
of
autism
in
18-month-old
infants.
From both
the
initial study
of
sib-
lings
of
children with Autistic Disorder
and
from
the
larger epidemiological study involving
a
population
study
of
16,000
18-month-old infants, virtually
all the
children
failing
the
five-item criterion
on the
CHAT
ad-
ministered twice
(1
month apart) were
found
to
have
Autistic Disorder when diagnosed
at 20 and 42
months
(Baron-Cohen
et
al., 1992, 1996; Charman
et
al., 1998;
Cox
et
al.,
1999).
However,
the
epidemiological
study
has
indicated that
the
CHAT
was
less
sensitive
to
milder
symptoms
of
autism,
as
children later diagnosed with
PDDNOS, Asperger,
or
atypical autism
did not
routinely
fail
the
CHAT
at 18
months.
As a
tool
for
identifying
18-month-olds
at
risk
of
autism
from
a
normal popula-
tion,
the
CHAT appears
to be a
useful
tool,
but not an
entirely
sufficient
tool,
for
identifying
the
majority
of
children
who
will
fall
within
the
autistic spectrum.
An
unpublished variation
on the
CHAT
is The De-
velopmental Checklist, currently under development,
which expands
the
CHAT into
a
30-item checklist that
a
parent
alone
can
fill
out in
about
10
minutes
(Robins,
Fein, Barton,
&
Liss, 1999).
Pervasive
Developmental
Disorders
Screening
Test-Stage
1
(PDDST; Siegel, 1998)
is a
clinically
de-
rived parent questionnaire, divided into three
Stages,
each
of
which
is
targeted
at a
different
level
of
screen-
ing.
PDDST-Stage
1 is
aimed
for use in the
primary
care
setting, with items aimed incrementally
from
birth
to
36
months
of
age. Unlike
the
CHAT, this instrument
rates positive
as
well
as
negative symptoms,
and in-
cludes
a
number
of
questions concerning regression.
In
addition
to
sampling similar areas
as
other scales,
the
PDDST
also samples temperament, sensory responses,
motor stereotypies, attention, attachment,
and
peer
in-
terest. Parental report
of
stereotypic behaviors
is
prob-
ably
more accurate than observation,
due to the
greater
length
of
observation
and
varied environments.
The
tool
was
developed
in
several steps, beginning with
a
review
of
clinical records
of a
large number
of
children with
autism.
Test-retest
and
interrater (between parents)
re-
liabilities
were
then used
to
identify
problematic
items.
Follow-up clinical diagnosis
at age 5 was
used
to de-
termine
the
accuracy
of
screening. Finally,
the
instru-
ment
was
administered
to a
large number
of
children
with
mixed diagnoses
to set
cutoff
scores
and
algo-
rithms;
this work
is
ongoing.
A
significant cutoff
of
three
affirmative
answers
in
PDDST-Stage
1 has
been
established
for
further
diagnostic consideration
of an
Autistic Spectrum Disorder. This instrument
has not yet
been published
but is
available (see Appendix).
Australian Scale
for
Asperger's Syndrome (Garnett
&
Attwood, 1998)
is a
parent
or
teacher rating
scale
for
high-functioning
older children
on the
autistic spectrum
who
remain undetected
at
school age.
It
consists
of
24
questions rated with
a
score
from
1 to 6,
plus
a
check-
list
of 10
additional
yes or no
behavioral characteris-
tics.
If the
answer
is yes to the
majority
of
questions
in
the
scale
and
most
of the
ratings
are
between
2 and 6,
a
referral
for a
diagnostic assessment
of
autism should
be
made.
Referral
to
Early Intervention
or
Local
School
District
As
mandated
by
Public
Law
99-457,
and
reautho-
rized
as
Public
Law
105-17:
Individuals with Disabil-
ities Education Act- IDEA (1997), referral
for
early
in-
tervention must
be
initiated
by the
Level
1
professional.
Children less than
36
months
of age
should
be
referred

456
Filipek
et al.
to the
zero-to-three
service
system
in
their community;
children ages
36
months
and
older should
be
referred
to
the
local
school district.
Level
2:
Diagnosis
and
Evaluation
of
Autism
Once
a
child screens positive, he/she then should
be
referred
for an
appropriate assessment
by an
experienced
clinician,
one
with expertise
in the
diagnosis
of
devel-
opmental
disorders.
Although numerous studies show
that
autism
can be
reliably diagnosed
in
preschool chil-
dren, experienced clinicians
are
usually necessary
for ac-
curate
and
appropriate diagnosis (Gillberg, 1990; Lord,
Storoschuk, Rutter,
&
Pickles, 1993; Volkmar
et
al.,
1994). Many children
who
screen positive
and
enter into
more comprehensive assessments
may
NOT,
in the
end,
necessarily
be
considered
to
have autism
but may
have
a
range
of
other disorders—any
of
which
may
merit
in-
tervention
in
their
own
right. Accordingly,
it is
impor-
tant
that evaluators have
a
range
of
experience
in the di-
agnosis
and
assessment
of
developmental disabilities.
In
some cases children
may not
come
to
diagnosis
in the
preschool years
and it is
important that screening
en-
compass
children
in the
older
school-age
group
as
well.
It
is
therefore
the
consensus
of
this Panel that
Level
2
evaluations should
be
performed only
by
pro-
fessionals
who
have specific expertise
in the
evalua-
tion
and
treatment
of
autism.
At
the
present time
no
biological marker
or
simple
laboratory test
or
procedure exists
for the
diagnosis
of
autism
and
related conditions. Clinicians must, accord-
ingly,
rely
on
their clinical judgment, aided
by
guides
to
diagnosis such
as
DSM-IV
and
ICD-10,
as
well
as by
the
results
of
various assessment instruments, rating
scales,
or
checklists.
The
latter instruments
do NOT
sub-
stitute
for the
diagnosis
by an
experienced clinician.
Interdisciplinary collaboration
and
consultation
are
indicated
in the
diagnosis
and
assessment
of
children with
autism
and
related
difficulties.
The
needs
for
service
from
the
various providers will vary depending
on the
needs
of
the
child,
family,
symptomatic presentation, clinical
context,
and so
forth
(Volkmar, Cook, Pomeroy, Real-
muto,
&
Tanguay,
in
press).
The
efforts
may
involve
nu-
merous
specialists,
including
psychologists,
neurologists,
speech pathologists
and
audiologists, pediatricians, child
psychiatrists, occupational therapists,
and
physical ther-
apists
as
well
as
educators
or
special
educators.
When
assessments
are
interdisciplinary
in
nature,
it is
critical
that
the
service providers coordinate their work
to
avoid
duplication
of
effort
and
maximize
efficient
use of
time.
It
also
is
essential that
one
provider assume
a
major
role
as the
"Coordinator
of the
Assessment."
Research
from
many studies suggests that
the
autis-
tic
spectrum disorders
are not
qualitatively different
from
Autistic Disorder,
but
differ
primarily
in
terms
of
severity
or the
presence
of
repetitive
or
sensory
behav-
iors. This distinction
is
often
confounded
by
higher ver-
bal
skills
in
individuals
with
autistic spectrum
disorders
other than Autistic Disorder.
It is
important
to
insure
that
any
individual with
an
autistic spectrum disorder
receive adequate assessments
and
appropriate diag-
noses. Factors that
are not
specific
to
autism, including
degree
of
language impairment, mental handicap,
and
presence
of
nonspecific behavior disorders such
as
over-
activity
and
aggression, significantly
affect
outcome
and
treatment
of
individuals with autism. Diagnostic eval-
uations
must address these issues
and
provide contin-
ued
monitoring
of
nonspecific
as
well
as
autism-related
impairments across development.
In
addition
to its
important role
in
diagnosis,
a
com-
prehensive assessment
has an
essential
role
in
treatment
planning.
Although
the
focus
of
this paper
is on
screen-
ing
and
diagnosis,
the
other important
functions
of as-
sessment
and
treatment
are
essential.
As a
practical mat-
ter,
the
assessment should
be
concerned
not
only with
diagnosis
as
such
but
with
obtaining
information
on
pat-
terns
of
strengths
and
weaknesses important
to
inter-
vention.
Indeed
the
results
of the
formal assessments
are
often
not as
important
as the
less formal,
but
clinically
informative,
observations
of the
child during
the as-
sessment.
Parents should
be
intimately involved
in
this
process.
The
assessment should also
be
careful
to
note
areas
of
strength
as
well
as
weakness.
Expanded
Medical
and
Neurological
Evaluation
Birth,
Medical, Developmental,
and
Family Histories
This evaluation would expand
on
that already per-
formed
at
Level
1.
Besides delineating
social,
commu-
nication,
and
behavior characteristics,
the
focus should
be on the
search
for
acquired brain
injury,
comorbid con-
ditions,
or
other medical
or
neurologic
difficulties
com-
mon
to
autism.
Birth
History.
An
increase
of
only mild obstetrical
complications
was
noted
in the
deliveries
of
autistic
in-
dividuals,
which
was
independent
of
maternal
age or
parity,
making
a
causal relationship unlikely (Bolton
et
al., 1997). Specifically,
no
association
was
found
be-
tween
autism
and
gestational
age or
occurrence
of
vagi-
nal
bleeding, infection, diabetes, toxemia, maternal age,
or
prior abortions (Bolton
et
al., 1997; Cryan, Byrne,
O'Donovan,
&
O'Callaghan, 1996; Ghaziuddin, Shakal,
&
Tsai, 1995; Piven
et
al., 1993; Rapin, 1996a). There

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
457
was
also
no
association between autism
and
birth
weight, induction
of
labor, breech presentation, forceps
or
cesarian
delivery, prolonged labor, neonatal depres-
sion,
need
for
intensive
care
or
mechanical
ventilation,
neonatal seizures,
or
prolonged neonatal hospitalization
(Bolton
et
al., 1997; Fein
et
al., 1997; Piven
et
al.,
1993;
Rapin, 1996a). Although several prior studies indicated
a
possible
association between autism
and
increased
ob-
stetrical risk factors, although mild, these have
not
been
borne
out
(Bryson, Smith,
&
Eastwood, 1988b; Deykin
&
MacMahon, 1980; Finegan
&
Quarrington, 1979; Fol-
stein
&
Rutter, 1977a; Folstein
&
Rutter, 1977b; Gill-
berg
&
Gillberg, 1983; Levy, Zoltak,
&
Saelens, 1988;
Lord, Mulloy, Wendelboe,
&
Schopler, 1991; Mason-
Brothers
et
al., 1987, 1990; Nelson, 1991; Tsai, 1987).
Many
of
these studies
did not
correct
for the
strong
in-
fluence
of
maternal parity (e.g., reproductive stoppage
effect),
which accounted
for the
differences
in at
least
two
studies (Lord
et
al., 1991; Piven
et
al., 1993).
Medical
and
Developmental History. Detailed his-
tory should
be
aimed
at
determining developmental mile-
stones, developmental regression
at any
age,
identifying
any
encephalopathic events, history
of
attention deficit
disorder,
seizure
disorder,
depression,
mania, trouble-
some behaviors such
as
irritability,
self-injury,
sleep
or
eating disturbances,
and
pica
for
possible lead exposure.
Family
History. Autism, mental retardation, fragile
X
syndrome,
and
tuberous sclerosis should specifically
be
inquired about
in
nuclear
and
extended
family
be-
cause
of
their implications regarding
the
need
for
chro-
mosomal
or
genetic evaluation.
In
addition,
the
presence
of
affective disorder
and
anxiety disorder should
be in-
vestigated,
as
these
disorders have been shown
to be in-
creased
in
families
of
autistic individuals
and
increase
the
burden
to the
family
(Bolton
et
al., 1994; DeLong,
1994; DeLong
&
Nohria, 1994; Fombonne, Bolton,
Prior, Jordan,
&
Rutter, 1997; Piven
et
al., 1990, 1994).
Autism:
Family studies have shown that there
is a
50- to
100-fold increase
in the
rate
of
autism
in
first-
degree
relatives (Rutter, Bailey, Simonoff,
&
Pickles,
1997;
Simonoff,
1998). Recent
family
studies have shown
that
first-degree
relatives
of
autistic probands have ele-
vated rates
of
social difficulties, characterized
by
social
withdrawal
or
awkwardness,
and
have
a
higher
incidence
of
cognitive
and
executive
function
deficits, anxiety,
and
affective
disorders (Bailey, Palferman, Heavey,
& Le
Couteur,
1998b;
DeLong, 1994; DeLong
&,
Nohria,
1994; Hughes, Leboyer,
&
Bouvard, 1997; Piven
et
al.,
1990, 1991a, 1994, 1997). Extended relatives
in
both sim-
plex
and
multiplex families
(i.e.,
those
with
more than
one
autistic child)
had a
higher rate
of
social
and
com-
munication
deficits
and
stereotyped behaviors than
did
relatives
of
children with Down syndrome (Bolton
et
al.,
1994; Piven, Palmer, Jacobi, Childress,
&
Arndt, 1997a).
These impairments were milder
but
qualitatively very
similar
to
autism, with
relatively
normal
intellectual
func-
tion
(IQ).
In
addition,
first-degree
relatives demonstrated
higher verbal than nonverbal
IQ
scores,
with
significant
discrepancies noted between
the
scores (Fombonne
et
al.,
1997).
The first
twin study
of 11
monozygotic (MZ) pairs
reported
a
concordance rate
of
over
36% for
Infantile
Autism,
with
no
concordance
in 10
dizygotic (DZ) twin
pairs (Folstein
&
Rutter, 1977a, 1977b). However,
a
total
of
82% of
these
MZ and 10% of the DZ
twin
pairs were
concordant
for
some
form
of
cognitive,
social,
or
lan-
guage deficits.
A
recent study
of 28 MZ
twin pairs (in-
cluding
the
original
11
pairs) showed
a
concordance rate
of
60% for
DSM-IV Autistic Disorder,
71% for the
broader spectrum
of PDD or
Atypical Autism,
and 92%
for
an
even broader phenotype
of
social
and
communi-
cation
deficits
with stereotyped behaviors that nonetheless
were clearly differentiated
from
normal (Bailey
et
al.,
1995;
Le
Couteur
et
al., 1996).
Fragile
X:
Numerous early reports noted
a
highly
significant
association between fragile
X
(FraX)
and
autism,
in up to 25% of
autistic individuals (Blomquist
et
al., 1985; Brown
et
al., 1986; Gillberg &Wahlstrom,
1985; Wahlstrom, Gillberg, Gustavson,
&
Holmgren,
1986), although this association
was and
remains con-
troversial
(I. L.
Cohen
et
al., 1991). While other stud-
ies
report
a
much lower incidence
of
FraX
(3-7%)
in
patients
with autism (Bailey
et
al., 1993a; Bolton
&
Rutter, 1990; Piven, Gayle, Landa, Wzorek,
&
Folstein,
1991b), another study
found
no
evidence
of
FraX using
cytogenetic (not
DNA
analysis) techniques (Hashimoto,
Shimizu,
&
Kawasaki, 1993). Molecular genetic analy-
ses of a
large cohort
of
autistic individuals
found
FraX
in
only three siblings:
one
girl with Autistic Disorder,
her
brother with Atypical Autism,
and a
second brother
without
autistic features
but
with
a
learning disability
(Klauck
et
al., 1997). Because
the
presence
of
FraX
genotype
did not
correlate with
the
autism phenotype,
they
concluded that
the
association between autism
and
fragile
X
does
not
exist. Therefore, although
few
chil-
dren with autism have fragile
X
syndrome, children
with fragile
X
syndrome
often have
autistic
sympto-
matology (Feinstein
&
Reiss,
1998).
Tuberous
Sclerosis
Complex: Tuberous
sclerosis
complex (TSC)
is a
neurocutaneous disorder that also
af-
fects
other organ systems, including
the
heart
and
kid-
neys.
TSC has
been linked
to two
distinct gene loci:
TSC1
to
chromosome
9
(9q34)
and
TSC2
to
chromo-
some
16
(16pl3.3) (OMIM™, 1997).
The
phenotypes
of
TSC1
and
TSC2 have been considered identical; how-

458
Filipek
et al.
ever,
a
recent
study noted that mental handicap
and
spo-
radic rather than familial occurrence
may be
more fre-
quently associated with
the
TSC2 genotype (Jones
et
al.,
1997; OMIM™, 1997), although this finding
may
also
represent
an
ascertainment bias. Depigmented macules
(shaped like
an
ash-leaf (Fitzpatrick,
1991))
are
usually
the
first
visible sign
of the
disease. They
are
often
visu-
alized only with
the use of an
ultraviolet light (Wood's
lamp).
Facial
angiofibroma, formerly called adenoma
sebaceum,
and
shagreen patches over
the
lower back
are
also
characteristic,
but
often
do not
appear until late
childhood
or
early adolescence (Webb, Clarke, Fryer,
&
Osborne,
1996).
The
major intracerebral lesions
are the
tubers
which
consist
of
histiogenic
malformations
of
both
neuronal
and
glial
elements with giant heterotopic cells.
They
are
characteristically located
in the
subependymal
regions
and in the
cortex, predominantly
in the
frontal
lobes
(Braffman
&
Naidich, 1994; Harrison
&
Bolton,
1997; Truhan
&
Filipek, 1993).
TSC has
been strongly
associated
with
autism. Estimates suggest that
17% to
over
60% of
mentally retarded individuals
with
TSC are
also autistic, most commonly co-occurring with epilepsy
(Curatolo
et
al., 1991; Dykens
&
Volkmar, 1997; Gill-
berg, Gillberg,
&
Ahlsen, 1994; Harrison
&
Bolton,
1997; Hunt
&
Shepherd, 1993; Riikonen
&
Simell, 1990;
Smalley, Smith,
&
Tanguay, 1991; Smalley, Tanguay,
Smith,
&
Gutierrez,
1992).
In
contrast,
the
number
of
autistic
individuals with
TSC has
been estimated
to be
between
0.4 and 3% in
epidemiological studies (Dykens
&
Volkmar, 1997; Gillberg
et
al., 1991; Lotter, 1967;
Olsson,
Steffenburg,
&
Gillberg, 1988; Ritvo
et
al., 1990;
Smalley
et
al., 1992). This
rate
increased
to 8 to 14% in
autistic subjects with epilepsy (Gillberg, 1991; Riikonen
&
Amnell,
1981).
A
recent report noted
an
inverse cor-
relation between
IQ and the
number
of
tubers identified
on
MRI in a
small cohort
of
individuals with TSC; those
individuals with both
TSC and
autism
not
only
had the
most tubers,
but
also
had
tubers located
in the
temporal
lobes,
a finding not
seen
in
nonautistic subjects
with
TSC
(Bolton
&
Griffiths,
1997).
Pertinent
Positives
on the
Physical
and
Neurological
Examination
Examination
of
persons with autism
may
require
more time because
of the
likelihood
of
poor cooperation
by
a
patient with impaired communication
and
behav-
ioral problems. Severe unexplained behavioral changes
may
be due to an
undiagnosed intercurrent illness (e.g.,
dental
abscess,
gastric ulcer,
or ear
infection)
or an un-
recognized
injury.
In
some individuals,
an
adequate med-
ical
or
dental examination
may
require sedation.
Head Circumference.
The
head circumference
in
children with autism
is
larger
on
average than
in
typi-
cally
developing children (Bailey
et
al., 1995; Bolton
et
al., 1994; Davidovitch, Patterson,
&
Gartside, 1996;
Lainhart
et
al., 1997; Woodhouse
et
al.,
1996).
The
same
has
been noted with postmortem brain weights (Bailey
et
al., 1993b, 1998a; Bauman, 1992b, 1996; Bauman
&
Kemper, 1994, 1997; Courchesne, Muller,
&
Saitoh,
1999). Only
a
small proportion
of
children with autism
have
frank
macrocephaly with head circumferences
above
the
98th percentile,
but the
distribution
of the
measures
is
clearly
shifted
upward
with
the
mean
in
autism
falling
at
about
the
75th percentile (Bailey
et.
al.,
1995;
Bolton
et
al., 1994;
Davidovitch
et
al., 1996;
Fili-
pek
et
al., 1992b; Lainhart
et
al., 1997; Rapin, 1996b;
Woodhouse
et
al.,
1996).
It
also
appears that
a
large head
size
may not
necessarily
be
present
at
birth,
but may ap-
pear
in
early
to
mid-childhood
due to an
increased rate
of
brain growth (Lainhart
et
al., 1997; Mason-Brothers
et
al., 1987, 1990).
The
phenomenon
of a
larger head
size without
frank
neuropathology
in
children with
autism
is
widely acknowledged (Bailey
et
al., 1995;
Bolton
et
al., 1994; Davidovitch
et
al., 1996; Lainhart
et
al., 1997; Rapin,
1996b;
Woodhouse
et
al., 1996). Bar-
ring
lateralizing signs
on the
remainder
of the
examina-
tion,
routine neuroimaging
for the
sole
finding
of a
head
circumference
greater
than
the
98th
percentile
in an
autistic individual
is not
warranted (Filipek, 1996, 1999;
Filipek, Kennedy,
&
Caviness, 1992a; Minshew, 1996b;
Minshew
&
Dombrowski,
1994).
General Examination. Given
the
high prevalence
of
autism
in
TSC,
an
examination using
a
hand-held
ul-
traviolet light (Wood's lamp) should
be
performed
on
every child presenting with possible autism
as an
ini-
tial screen
for
tuberous sclerosis (Reich, Lenoir, Malvy,
Perrot,
&
Sauvage, 1997; Smalley
et
al., 1992). Also,
unusual
or
dysmorphic features
(of
facies, limb, stature,
etc) should
be
noted, for,
if
present, they suggest
the
need
for
consultation with
a
geneticist.
Mental
Status Examination.
The
mental status
ex-
amination
should include
the
evaluation
of
social inter-
actions, play, language,
and
communicative
function.
Social interactions should
be
queried
if
observation
in
the
office
proves inconclusive. Probes should
be
included
for
age-appropriate friendships,
who
initiates contact
with
the
friends (child
or
parent), interest
in
other chil-
dren,
and the
role within
the
friendship (e.g., leader
of
much
younger peers
or
follower
of
much older peers with
little
or no
same-aged peers). Deficient play skills
are a
hallmark
of
autism, independent
of IQ
(Rapin, 1996b).
An
adequate period
of
observation
of the
child's
use of
age-appropriate miniature toys
in the
examination room

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
459
is
essential
to
discriminate between simple manipulative
(banging
or
mouthing)
or
stereotypic (lining
up) use of
toys,
and
actual functional
or
symbolic (using
one
item
to
represent
another)
pretend
play
(Sigman
&
Ungerer,
1984; Stone, Lemanek,
Fishel,
Fernandez,
&
Altemeier,
1990).
For
example, classifying
or
sorting miniature fig-
ures,
which
may be
subtle,
is a
typical stereotypic
be-
havior
of
higher
functioning
children with autism which
may be
mistaken
for
appropriate play
if
only given
a
brief glance.
Cranial Nerve Examination. Clinical cranial nerve
abnormalities were only infrequently noted
in a
large
sample
of
children with autism (Bauman, 1992a; Rapin,
1996b).
Motor
Examination. Impairments
of
gross
and
fine
motor
function
have been reported
in
autistic individu-
als,
and are
more severe
in
those with lower
IQ
(Rapin,
1996b).
Hypotonia
was
found
in
about
25% of 176
chil-
dren with autism
and in 33% of 110
nonautistic mentally
retarded children, whereas spasticity
was
found
in
less
than
5% of
either group (exclusionary criteria
for
this
sample included
the
presence
of
lateralizing gross motor
findings).
Limb apraxia
was
noted
in
almost
30% of
autistic
children
with
normal
IQ, in 75% of
retarded
autistic children,
and in 56% of the
nonautistic retarded
control group.
A
third significant finding
was the
pres-
ence
of
observed motor stereotypies
in
over
40% of
chil-
dren with autism
(in
contrast
to a
much higher preva-
lence
by
parental report),
and in
over
60% of
those with
low IQ, but in
only
13% of the
nonautistic control group.
Autism
Diagnostic
Tools
The
diagnosis
of
autism
as
distinct
from
other
de-
velopmental disabilities requires
a
comprehensive multi-
disciplinary approach.
The
evaluation should include
measures
of
parental report, child observation
and in-
teractions,
and
clinical judgment. Assessments should
include cognitive, adaptive behavior,
and
diagnostic
measures.
Diagnostic Parental Interviews/Questionnaires
The
Gilliam Autism Rating Scale (GARS; Gilliam,
1995)
is a
checklist
designed
to be
used
by
parents,
teachers,
and
professionals
to
help both
identify
and es-
timate
the
severity
of
symptoms
of
autism
in
individu-
als age 3 to 22
years.
Items
are
based
on
DSM-IV (APA,
1994)
and are
grouped into
four
subtests
(a)
stereotyped
behaviors
(b)
communication,
(c)
social
interaction,
and
(d) an
optional subtest which describes development
in
the
first
3
years
of
life. This tool provides
a
global rat-
ing
of
autistic symptomatology.
The
Parent Interview
for
Autism
(PIA; Stone
&
Hogan, 1993)
is a
structured interview designed
to
gather diagnostically relevant information
from
parents
of
young
children
suspected
of
having
autism.
The PIA
consists
of 118
items, organized into
11
dimensions
as-
sessing
various aspects
of
social behavior, commu-
nicative functioning, repetitive activities,
and
sensory
behaviors. Items
are
phrased
as
questions about spe-
cific
observable behaviors,
and
ratings
of the
frequency
of
occurrence
are
obtained. Internal consistency
and
test-retest
reliability were adequate,
and
concurrent
validity with
the DSM
(APA, 1994)
and the
Childhood
Autism
Rating Scale (CARS; Schopler, Reichler,
&
Rochen-Renner, 1988)
was
demonstrated. Significant
group differences between young children with autism
and
young children
with
developmental delays
or
men-
tal
retardation were obtained
for the
total score
as
well
as the
dimensions
of
Relating, Imitation, Peer Inter-
actions, Imaginative Play, Language Understanding,
and
Nonverbal Communication.
The PIA
takes about
45
minutes
to
administer.
The
Pervasive Developmental Disorders Screen-
ing
Test- Stage
2
(PDDST; Siegel, 1998).
The
PDDST
is a
clinically
derived
parent
questionnaire
divided
into
three Stages, each
of
which
is
targeted
at a
different
level
of
screening. Further details
on
this instrument
were included
earlier
under Level
1
Screening. PDDST-
Stage
2 was
developed
for
Developmental Disorders
Clinics,
and
PDDST-Stage
3 for
Autism
or PDD
Clin-
ics. Significant
cutoffs
have been established
for
fur-
ther diagnostic consideration
of an
Autistic Spectrum
Disorder:
four
affirmative
answers
in
PDDST-Stage
2,
and
six
affirmative answers
in
PDDST-Stage
3.
This
instrument
has not yet
been published
but is
available
(see Appendix).
The
Autism Diagnostic Interview-Revised (ADI-R);
Le
Couteur
et
al., 1989; Lord
et
al., 1993, 1997; Lord,
Rutter,
& Le
Couteur, 1994)
is a
comprehensive struc-
tured parent interview that probes
for
autistic symp-
toms
in the
spheres
of
social relatedness, communica-
tion,
and
ritualistic
or
perseverative behaviors.
It
permits DSM-IV (APA, 1994)
and
ICD-10 (WHO,
1992, 1993) diagnoses
within
the
autistic spectrum,
with definitive
threshold
scores
for the
diagnosis
of
Autistic
Disorder.
The
ADI-R (and ADOS-G)
are
cur-
rently
the
"gold
standard" diagnostic instruments
in all
appropriate autism research
protocols.
Because admin-
istration
of the
ADI-R takes approximately
1
hour
and
requires specific training
and
validation procedures,
its
utility
to
primary
care
or
clinical specialty profes-
sionals
is
probably
less
than
its
import
in the
research
community.

460
Filipek
et al.
Diagnostic
Observation Instruments
The
Childhood
Autism
Rating
Scale (CARS;
Schopler
et
al., 1988)
is a
15-item structured interview
and
observation instrument which
is
suitable
for use
with
any
child over
24
months
of
age. Each
of the 15
items
uses
a
7-point rating scale
to
indicate
the
degree
to
which
the
child's behavior deviates
from
an
age-appropriate
norm;
in
addition,
it
distinguishes mild-to-moderate
from
severe
autism.
The
CARS
is
widely recognized
and
used
as
a
reliable instrument
for the
diagnosis
of
autism,
and
takes
approximately
30 to 45
minutes
to
administer
(Schopler, Reichler, DeVellis,
&
Daly, 1980).
The
Screening
Tool
for
Autism
in
Two-Year-Olds
(STAT; Stone, 1998a,
1998b)
is a
theoretically
and em-
pirically derived, interactive measure
to be
administered
to
children ages
24 to 35
months
by
various early child-
hood professionals.
The
STAT, still
in
development,
is
designed
to
differentiate autism
from
other develop-
mental
disorders, thus
it is a
Level
2
screening instru-
ment.
In a
20-minute play interaction involving
12 ac-
tivities,
the
tool samples
three
areas: play (both pretend
and
reciprocal social play), motor imitation,
and
non-
verbal
communicative development.
The
tasks used
on
the
STAT
were those that best differentiated between
children
with autism
and
those
with other developmen-
tal
disorders
in
studies
of
matched groups
of
two-year-
olds
on a
wide range
of
measures. There
is a
manual with
clear instructions
for
administration
and
scoring.
In a
pilot
study
involving
40
children,
the
tool correctly clas-
sified
100%
of
children with autism
(n = 8) and 97% of
children with other developmental delays
(n = 32)
using
a
criterion
of
failure
on two of the
three areas. Thus,
demonstrating very strong sensitivity
and
specificity.
Current work
on the
tool
is
focused
on the
empirical
determination
of
best
cutoffs
and
algorithm scoring.
The
Autism
Diagnostic
Observation
Schedule-
Generic (ADOS-G; DiLavore, Lord,
&
Rutter, 1995;
Lord, 1998; Lord
et
al., 1989)
is a
semi-structured
ob-
servational assessment
in
four
modules that includes
investigator-directed activities
to
evaluate communi-
cation,
reciprocal
social
interaction, play, stereotypic
behavior, restricted interests,
and
other abnormal
be-
haviors,
in
autistic individuals ranging
from
nonverbal
preschool
children
to
verbal autistic adults.
It
takes
ap-
proximately
30 to 45
minutes
to
administer.
It
also per-
mits DSM-IV (APA, 1994)
and
ICD-10 (WHO, 1992,
1993) diagnoses within
the
autistic spectrum, with
de-
finitive
threshold scores
for the
diagnosis
of
Autistic
Disorder.
As
with
the
ADI-R, administration
of the
ADOS-G
requires
specific training
and
validation pro-
cedures.
As
mentioned earlier,
the
ADOS-G
and
ADI-R
are the two
"gold
standard" diagnostic instruments
in
all
appropriate autism research protocols. Because
ad-
ministration
of the
ADOS-G takes
less
time than
the
ADI-R,
many autism specialty professionals
are
using
this
instrument
in
their clinical practices; albeit pre-
dominantly
abroad where clinical time
is not as
limited
as
with managed care
in the US.
Differential
Diagnosis
of
Autistic Spectrum
Disorders
The
differentiation
of
autism
from
other develop-
mental disorders
is
accomplished during Level
2.
Using
the
data
collected
from
the
various
evaluations,
pro-
fessionals must
also
determine
the
possible existence
of
comorbid disorders.
The
differential diagnosis
of
autism
includes consideration
of
mental retardation
not
associated
with autism, specific developmental dis-
orders
(e.g.,
of
language),
and
other psychiatric condi-
tions
(Volkmar
et
al.,
in
press).
Mental
retardation
or
borderline intelligence
often
coexists with autism. Individuals with severe
and
pro-
found
mental retardation
may
exhibit various character-
istics that
are
often
associated
with
autism, particularly
stereotyped movements.
Specific
developmental disorders, particularly
de-
velopmental
language disorders,
may
mimic autism
and
related conditions. Usually
in
children with language dis-
orders,
the
primary deficits
are in the
area
of
language
or
communication,
and
social skills
are
typically well-
preserved.
Schizophrenia occasionally
has its
onset
in
early
childhood. Usually there
is a
history
of
previously rel-
atively
normal development with
the
onset
of
charac-
teristic hallucinations
and
delusions typical
of
schizo-
phrenia.
However,
a
lack
of
typical social development
is
often
part
of the
premorbid history.
Selective
mutism
sometimes
is
confused with
autism
and
related conditions.
In
selective mutism
the
child's
ability
to
speak
in
some situations
is
preserved,
but
the
child
is
mute
in
other situations.
The
history
and
presentation
are
quite
different
from
that
of
autism.
Although
it is the
case
that children with autism
are
often
mute, their mutism
is
never
"selective"
nature.
Stereotyped movement disorder
is
characterized
by
motor mannerisms (stereotypies)
and the
presence
of
mental retardation.
A
diagnosis
of
stereotyped move-
ment
disorder
is not
made
if the
child meets criteria
for
one of the
pervasive developmental disorders.
Dementia occasionally
has its
onset
in
childhood.
In
some
cases
the
child will
fulfill
criteria
for
childhood
disintegrative disorder,
in
which
case
that diagnosis
as

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
461
well
as the
specific medical diagnosis causing
the de-
mentia
can be
made.
The
typical pattern
of
dementia
of
childhood onset
is one of
progressive deterioration
in
mental
and
motor
functioning.
Obsessive compulsive disorder (OCD) presents
in
some children with unusual interests
and
behaviors.
However,
social
skills
are
preserved,
as are
language
and
communication skills. When social skill deficits
or
communication
deficits
are
present
in
OCD, they
are
qualitatively
different
from
those
found
in
autism.
Schizoid personality disorder
is
characterized
by
relative
isolation, with
the
ability
to
relate normally
in
some contexts. However, personality disorders
are not
diagnosed before
the age of 18
years
by
current DSM-
IV
standards (APA, 1994).
Avoidant
personality disorder
is
characterized
by
anxiety
in
dealing with social situations.
Reactive attachment disorder usually presents
with
a
history
of
very severe neglect
or
abuse;
the
social
deficits
of
reactive
attachment disorder tend
to
remit dra-
matically
in
response
to a
more appropriate environment.
Specific
Evaluations
to
Determine
the
Developmental
Profile
Speech-Language-Communication
Evaluation
Language pathologists
are
independent health care
providers
who
have responsibilities
at the
levels
of
screening (Level
1),
diagnosis
and
evaluation (Level
2)
of
autism. Evaluation
at
both levels
may be
accom-
plished
in a
single session rather than
in
discrete seg-
ments. Standardized speech, language,
and
communi-
cation assessments conducted
in
formal testing situations
may
provide important information about specific
pa-
rameters
of
speech
and
language
functioning.
However,
such assessments
may
provide only limited
information
about social-pragmatic abilities
(i.e.,
use of
language
and
communicative abilities
in
social contexts), which
are
characteristically limited
in the
autistic spectrum
disorders
(Allen, 1989; Allen
&
Rapin, 1992; Lord
&
Paul, 1997; Stone, Ousley, Yoder, Hogan,
&
Hepburn,
1997; Wetherby, Prizant,
&
Hutchinson, 1998; Wetherby,
Schuler,
&
Prizant, 1997; Wetherby, Yonclas,
&
Bryan,
1989).
Therefore,
a
variety
of
strategies should
be
used, including direct assessment, naturalistic observa-
tion,
and
interviewing significant
others,
including par-
ents
and
educators,
who can be
invaluable sources
of
information
(Prizant
&
Wetherby, 1993; Stone
&
Caro-
Martinez,
1990).
Each
of
these strategies
has the
poten-
tial
to
provide qualitatively
different
information
about
a
child's
speech,
language,
and
communicative abilities
that
may
ultimately
be
integrated
to
develop
a
profile
for
differential
diagnosis
and
intervention planning.
Ob-
servations
should include
a
child's interactions with
a
variety
of
persons
including family
members
and
peers,
as
well
as
professionals, because variability
in
commu-
nicative
functioning
across persons
and
settings
is to be
expected (Wetherby
et
al., 1997). Specific domains
should
be
addressed
in a
comprehensive assessment
for
both
preverbal
and
verbal individuals, taking into
ac-
count
their age, cognitive level,
and
socioemotional abil-
ities (Wetherby
et
al., 1998).
Receptive Language
and
Communication. Clinical
experience suggests that caregivers
or
professionals
often
assume that
a
child understands
others'
commu-
nicative signals
and may
interpret
a
lack
of
response
to
gestures
or
speech
as
noncompliant
or
uncooperative
behavior. Children's ability
to
respond
to and use
com-
municative
gestures
and
vocalizations should
be
docu-
mented,
with
and
without
the
support
of
situational
cues. True linguistic comprehension
is
evidenced when
children
can
comprehend words without situational
or
nonverbal
cues, especially
when
words refer
to
persons,
objects,
and
events outside
of the
immediate environ-
ment.
At
higher levels
of
ability,
assessment should
ad-
dress comprehension
of
different
simple
and
complex
sentence types (e.g., negatives, questions, causal, con-
ditional),
of
ongoing discourse (e.g., ability
to
under-
stand
a
story
or
sequence
of
events),
and of
nonliteral
language
(i.e., idioms, sarcasm). Guidelines
and
pro-
cedures
for
more in-depth assessment
of
comprehen-
sion
for
preverbal
and
verbal individuals
are
available
(Lund
&
Duchan, 1993; Miller
&
Paul,
1995).
Expressive
Language
and
Communication.
The
primary focus
in
this domain
is
documentation
of
(a)
communicative means,
the
behaviors
by
which
a
child
expresses intentions, emotions,
and
physiological states,
and
(b)
communicative
functions,
the
purposes
for
which
a
child communicates (Prizant
&
Wetherby, 1993).
Communicative
means
in
preintentional children
may
include
a
variety
of
nonverbal
and
vocal behaviors
such
as
body posture
and
movement,
facial
expression,
directed gaze
and
gaze aversion,
and
vocalizations.
In
developmentally
more advanced children, intentional
use
of
idiosyncratic
(e.g.,
physically leading others)
and
con-
ventional
(e.g., pointing, nodding, waving) gestures,
as
well
as
vocalizations
and
emerging word forms should
be
documented (Schuler, Prizant,
&
Wetherby, 1997).
Children
with
autism have been
found
to
have
a
limited
repertoire
of
conventional gestures
and
vocalizations
(Stone
et
al., 1997; Wetherby
et
al., 1998), even when
compared
to
children with other developmental language
disorders.

462
Filipek
et al.
Communicative
functions
expressed preverbally
or
verbally
may
include communicating
for
relatively
nonsocial purposes
to
have immediate needs
met
(e.g.,
requesting objects
or
actions, protesting),
or for
more
so-
cial purposes such
as to
bring attention
to
oneself (e.g.,
requesting
social
routines,
greeting,
calling)
and
com-
municating
to
bring others' attention
to
interesting
objects
or
events (e.g., pointing
to or
commenting
on in-
teresting events). Young children with autism com-
municate primarily
for
relatively nonsocial purposes
when
compared
to
children with developmental language
disorders (Mundy, Sigman,
&
Kasari, 1990; Wetherby
et
al., 1989, 1998).
In
addition,
the
rate
of
communica-
tive
acts
and a
child's
ability
to
persist
in
repairing com-
munication
breakdowns should also
be
documented.
As-
sessment should also document
forms
and
functions
of
unconventional
nonverbal (e.g., disruptive behaviors)
and
verbal
(e.g., immediate
and
delayed echolalia, persever-
ative
speech, incessant questioning) communicative
be-
havior (Carr
&
Durand, 1985; Prizant
&
Rydell, 1993).
For
verbal children able
to
engage
in
conversation,
collection
and
analysis
of
spontaneous
language sam-
ples supplement scores
on
formal language tests (see
below).
It
provides information about
a
child's narra-
tive
and
conversational discourse, including ability
to
initiate, maintain,
and
terminate conversational inter-
actions following acceptable conventions
of
discourse,
the
ability
to
maintain topic
and
follow
topics intro-
duced
by
others,
and to
take
the
perspective
of
others
by
providing sufficient,
but not
excessive,
amounts
of
background
or
known information (Prizant, Wetherby,
Schuler,
&
Rydell, 1997).
Voice
and
Speech
Production. Some young children
with
autism
may not be
able
to
acquire
and use
speech
as
a
primary mode
of
communication,
due to
severity
of
cognitive impairment, severe
to
profound
hearing loss,
or
severe language comprehension disorders. Less fre-
quently, specific
neuromotor
speech
disorders
are in-
volved, including developmental verbal dyspraxia,
a
dys-
function
in the
ability
to
plan
the
coordinated movements
to
produce intelligible sequences
of
speech sounds,
or
dysarthria,
a
weakness
or
lack
of
control
of the
oral mus-
culature.
For
nonspeaking individuals,
or for
those with
speech
of
limited intelligibility, assessment should
ad-
dress quality
and
variety
of
communicative vocalizations
and
oral-motor
abilities
(e.g.,
chewing, swallowing).
Other aspects
of
speech
to
evaluate
in
more verbal indi-
viduals
include prosody, volume,
and
fluency
of
speech
production,
especially when disturbance
in
these para-
meters
negatively impact
on
communicative competence.
It
is
recommended that tests
be
used
for
speech-
language-communication assessments (Crais, 1995;
Wetherby
&
Prizant, 1992) that
(1)
focus
on
functions
of
communication;
(2)
analyze preverbal communica-
tion
(gestures, gaze, vocalizations);
(3)
assess social-
affective
signaling;
(4)
profile social, communicative
and
symbolic abilities;
(5)
directly assess
the
child,
not
only
rely
on
parental
report;
(6)
permit
observa-
tion
of
initiated
and
spontaneous communication,
and
(7)
directly involve caregivers during
the
assessment
(Wetherby
&
Prizant, 1992).
The
most widely used
tests
for
children with language
and
communication
disorders
are
listed
in
Table
V,
which
was
adapted
from
Wetherby
and
Prizant (1992)
and
Crais (1995).
The
numbers
in
Table
V
referring
to the
relative
strengths
and
weaknesses
reflect
the
seven
points
outlined above.
Cognitive Evaluation
Although
the
Level
1
professional
may
have
obtained
a
rough estimate
of the
child's cognitive sta-
tus
(mental age)
by
using screening tools
or
problem-
solving
milestone
charts from
preprinted
well-child
forms
and
textbooks, knowing
the
child's cognitive sta-
tus
is
important
in
determining
his
overall level
of
func-
tioning. This
is, in
turn, important when trying
to es-
tablish
a
discrepancy between
the
child's level
of
social
function
and the
overall cognitive
and
adaptive
function,
a key
criterion
in the
diagnosis
of
autism.
As
is
true
of
language pathologists, clinical psy-
chologists
and
developmental pediatricians
are
inde-
pendent
health care providers
who
have responsibili-
ties
at
both levels
of
screening
and
diagnosis, which
may
or may not be
accomplished
in a
single session
rather than
as
discrete segments. Additional visits
may
be
necessary
for the
child
to
adapt
to
change
as
well
as
to the
newness
of the
procedures
in
order
to
optimize
the
chances that
the
results accurately represent
the
child's
abilities.
While
the
diagnosis
of
autism
is
based
ultimately
on
clinical symptoms
and
early history,
the
results
of
cognitive assessment
may
assist
in
differen-
tial diagnosis,
as
well
as
provide important information
for
planning intervention
and
evaluating
its
effects.
Re-
search
has
demonstrated specific profiles
on
cognitive
batteries, with spared performance
on
tasks that rely
on
rote, mechanical,
or
perceptual processes,
and
deficient
performance
on
tasks requiring higher-order concep-
tual
processes, reasoning, interpretation, integration
or
abstraction
(Minshew
&
Goldstein, 1998). This pattern
is
present across multiple cognitive domains, with dis-
sociations between simple
and
complex processing
demonstrated
in
areas
of
language, memory, executive
function,
motor function, reading, mathematics,
and

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
463
perspective-taking (Klinger
&
Dawson, 1995; Min-
shew,
Goldstein, Taylor,
&
Siegel, 1994;
Ozonoff,
personal communication; Reed
&
Peterson, 1990; Rum-
sey &
Hamburger,
1988).
However,
few
direct com-
parison studies between autism
and
other disorders
have been conducted
and it is
possible that other dis-
orders
may
share some aspects
of
this information-
processing profile, which accounts
for the
differences
in
behavioral profile.
In
terms
of
intellectual assessment,
the
Wechsler
Intelligence Scale
for
Children/WISC-III (1991),
and
the
Wechsler Adult Intelligence Scale/WAIS-III (1997)
are the
tests
of
choice
for
higher
functioning
and
older
individuals with relatively good verbal language.
Nu-
merous studies have demonstrated
a
particular pattern
characteristic
of
autism: performance
IQ
(PIQ) higher
than
verbal
IQ
(VIQ)
and
specific inter-subtest scatter,
with
Block Design typically
the
highest subtest
and
Comprehension usually
the
lowest (see Lincoln, Allen,
&
Kilmasian, 1995; cited
in
Lincoln, Allen,
&
Kilman,
1995a.
However,
the
PIQ-VIQ
split
is
severity
de-
pendent. When Full-scale (FSIQ)
and VIQ are
both
above
70, 80% of
autistic individuals will have
no
sig-
nificant
VIQ-PIQ
disparity,
and the
remainder
are
evenly
divided between those
with
PIQ>VIQ
and
those
with
PIQ<VIQ (Siegel, Minshew,
&
Goldstein, 1996).
Thus, there
is
substantial variability
in the
intellectual
profiles
of
people
with
autism. However, although these
patterns
may be
typical, they
are by no
means univer-
sal and
cannot
be
used
for
diagnostic
or
differential
diagnostic purposes.
No
cognitive pattern confirms
or
excludes
a
diagnosis
of
autism.
Intellectual
testing
is
essential
for
educational
planning
and,
for
some children, assists
in
projecting
the
long-term level
of
disability.
It is
usually benefi-
cial
to
conduct these evaluations prior
to
entry into
kindergarten,
and to
collaborate with educational pro-
fessionals, including school psychologists,
in
order
to
address issues related
to
curriculum planning
and
school performance issues
often
addressed
by
school
psychologists.
In
autism, however,
it
should
be
recog-
nized
that
the
predictive validity
of
such testing
is not
necessarily high.
There
are
particular concerns about
the
validity
of
testing younger, lower
functioning,
and
nonverbal chil-
dren.
It is
critical that care
be
taken
in
choosing which
Table
V.
Strengths
and
Weaknesses
of
Specific Language Instrument
a
Instrument
Strengths
Weaknesses
Evaluation
of
only
receptive language
Peabody Picture Vocabulary Test-Revised
(PPVT-R; Dunn
&
Dunn, 1981)
Receptive One-Word Picture Vocabulary Test-Revised
(ROWPVT-R; Gardner, 1990b)
5
5
1-4,
6-7
1-4,
6-7
Evaluation
of
only expressive language
Expressive One- Word Picture Vocabulary Test-Revised
(EOWPVT-R; Gardner,
1990a)
5
1-4,
6-7
Evaluation
of
both receptive
and
expressive language
Birth
to
Three Developmental Scales
(Bangs
&
Dodson, 1986)
Clinical
Evaluation
of
Language Fundamentals-3
(CELF-3;
Semel, Wiig,
&
Secord, 1995)
Communication
and
Symbolic Behavior Scales
(CSBS; Wetherby
&
Prizant, 1993)
MacArthur
Communcative Development
Inventories (MCDI; Fenson
et
al., 1993)
Preschool Language
Scale-3
(PLS; Zimmerman,
Steiner,
&
Pond, 1992)
Receptive-Expressive-Emergent-Language
Scale-Revised (REEL-R; Bzoch
&
League, 1991)
Rosetti Infant-Toddler Language Scale (1990)
Sequenced Inventory
of
Communication
Development (SICD; Hedrick, Prather,
&
Tobin, 1984)
2, 4
1,
3, 5
limited
5
1-6
1-3,
5-7
1,
5
1, 2
limited
5
1-6
1,
2 &6
limited
5
6, 7
1-4,
6-7
7
limited
4
2-4,
6-7
3,
4, 6, 7
7
limited
3, 4, 7
a
The
numbers referring
to the
strengths
and
weaknesses
are
based
on the
seven points outlined
in the
text.
This table
was
adapted
from
Wetherby
and
Prizant (1992)
and
Crais (1995).

464
Filipek
et al.
intellectual test
to
administer
to
lower
functioning
or
nonverbal
individual with autism (Groden
&
Mann,
1988; Johnson-Martin, 1988; Klin
et
al., 1997; Watson
&
Marcus, 1988).
It is
recommended that tests
be
used
which
(1) are
appropriate
for
both mental
age and
chronological age;
(2)
provide
a
full
range
(in the
lower
direction)
of
standard
scores;
(3)
sample both verbal
and
nonverbal intellectual skills;
(4)
measure
and
score
separately verbal
and
nonverbal skills;
(5)
provide
an
overall index
of
ability;
and (6)
have norms which
are
current
and
relatively independent
of
social function.
With these principles
in
mind,
the
most appropriate
and
widely
used intellectual tests
for
younger, low-
or
non-
verbal individuals with autism
are
listed
in
Table
VI.
Clinical judgment
is
required
to
properly interpret
the
findings
of
these measures
for the
purpose
of
dif-
ferential
diagnosis. Additional information regarding
assessment
and
interpretation
of
psychological meas-
ures
is
provided
in
other resources (Jacobson
&
Mulick,
1996; Marcus, Lansing,
&
Schopler, 1993; Marcus
&
Stone,
1993).
Adaptive
Behavior
Evaluation
It
is
essential that
a
measure
of
adaptive
function
(the capability
for
self-sufficiency
in
acticities
of
daily
living)
be
collected
by the
psychologist
for any
child
evaluated
for an
associated mental handicap. Diagno-
sis of
mental retardation
relies
upon both subaverage
intellectual functioning
(IQ < 70) and
concurrent
deficits
in
adaptive functioning (APA, 1994).
The
Vineland Adaptive
Behavior
Scales
(VABS;
Sparrow, Balla,
&
Cicchetti, 1984b)
are
considered
to
be the
most widely used instrument
to
assess adaptive
behavior (Klin
et
al.,
1997).
The
scales
offer
an
estimate
of
adaptive development
in the
domains
of
Socialization
(interpersonal relationships, play
and
leisure time,
and
coping skills); Daily Living Skills (personal, domestic,
and
community skills); Motor
Skills
(gross
and
fine
motor);
and
Communication (receptive, expressive,
and
written
communication), with developmentally ordered
skills
for
each
area.
There
are
three available versions
of
the
Vineland:
(a) a
survey form used
as a
diagnostic
and
classification tool
for
children
and
adults (Sparrow
et
al., 1984b);
(b) an
expanded form
for use in
develop-
ing
educational
or
rehabilitation plans (Sparrow, Balla,
&
Cicchetti, 1984a);
and (c) a
classroom edition
to be
used
by
teachers (Sparrow, Balla,
&
Cicchetti, 1985).
Standard
scores,
percentile ranks, adaptive levels,
and
age
equivalents
are
available.
The
expanded edition
is
the
most
useful
for
autistic children, whose adaptive
function
is
usually lower than their cognitive level (Volk-
mar, Carter, Sparrow,
&
Cicchetti, 1993a). Recent sup-
plementary norms have been published
for
individuals
with
autism (Carter
et
al., 1998).
The
Scales
of
Independent
Behavior-Revised (SIB-
R;
Bruininks, Woodcock, Weatherman,
&
Hill, 1996)
is
a
comprehensive norm-referenced assessment
of
adap-
Table
VI.
Strengths
and
Weaknesses
of
Specific Cognitive Instruments
a
Instrument
Bayley
Scales
of
Infant
Development
II
(1993)
Mullen
Scales
of
Early
Learning
(1997)
Leiter-Revised (Roid
&
Miller, 1997)
Merrill-Palmer
(Stutsman,
1948)
Differential
Abilities
Scales (DAS;
Elliott,
1990)
Stanford-Binet
IV
(Thorndike, Hagen,
&
Sattler, 1986)
Strengths
1
: <42
months
3,5,6
1
: <60
months
3,4,5,6
6
highlights
visual
strengths
of
autistic
individuals
3:
verbal section
is
limited
5
1 :
extends
from
preschool
through
schoolage
3,4,5,6
Weaknesses
1:
not
normed
for >42
months
2:
standard
score
(SS)
> 50
4:
also mixes
in
social cannot
always
establish basal score
1:
basal
score
= 24
months
3:
nonverbal only
4,5
1:
basal score
= 18
months
4
6:
outdated
2:
SS to 45
only
3,4,5,6
1:
basal score
= 24
months
2: SS to 70
only—
highly
verbal,
long administration
a
The
numbers referring
to the
strengths
and
weaknesses
are
based
on the six
points outlined
in the
text.

Screening
and
Diagnosis
of
Autistic Spectrum
Disorders
465
live
and
maladaptive behavior,
for
ages ranging
from
infancy
through elderly adulthood. Fourteen Adaptive
Behavior Clusters
are
offered
in
three forms: Early
Development Form
(15-20
minutes), Short Form (15-
20
minutes), Full-scale Form
(45-60
minutes). These
cover motor skills, social interaction
and
communication
skills, personal living, self-care,
and
community
living
skills.
Age-equivalent scoring tables
are
included
in the
response booklets
for
each subscale, allowing examiners
to
get
immediate developmental information.
Sensorimotor Assessment
and
Occupational
Therapy
Evaluation
Sensorimotor Assessment: Diagnostic practice
has
conventionally placed little emphasis
on the
assessment
of
Sensorimotor behaviors
in
autism, with
the
excep-
tion
that stereotypies
are
part
of a
"restricted
behav-
ioral
repertoire"
(APA, 1994; Lord,
1995).
The
reasons
for
this include
the
facts that there
is a
dearth
of
sys-
tematic empirical research
in
this domain
and
that
the
existing literature
is
controversial with respect
to the
usefulness
of
these variables
for the
differential diag-
nosis
of
autism. Thus,
it
seems particularly important
to
document qualitative dimensions
of
early sensory
processing
and
motor behaviors (through both obser-
vation
and
parent report) rather than simply
assess
motor milestones during
infant
screenings.
Evaluation
of
Sensorimotor functions should focus
on
the
detection
and
localization
of
underlying neuro-
logic deficits, whereas occupational therapists have spe-
cific
expertise
in the
evaluation
of
their impact
on the
individual's functional skills
or
daily activities. Evalua-
tion
of
motor skills
is
particularly important
in
situations
where there
is a
question
of
delay, dysfunction,
or re-
gression
in
such skills,
to
document areas
of
strength
as
well
as
weakness
for
prognostic
and
intervention plan-
ning.
Assessment
of
gross
and
fine
motor skills
may be
completed
by
qualified professionals
(e.g.,
occupational
therapists
or
physical therapists) with
a
variety
of
stan-
dardized tools appropriate
to the
developmental level
of
the
individual with autism; however, adaptations
may be
needed
if the
person with autism
has
difficulty
under-
standing
the
tasks
or is
uncooperative. More important,
qualitative observations
of
praxis
(e.g.,
planning
or se-
quencing
of
novel complex movement patterns; imita-
tion
of
movements
or
pantomime; organization
of
goal-
directed actions with materials
in the
environment)
are
a
critical part
of the
sensorimotor evaluation
for
individuals with autism because these abilities
are
often
deficient (Rogers, Bennetto, McEvoy,
&
Pennington,
1996; Stone
&
Lemanek, 1990),
and
require specific
interventions. Repetitive motor stereotypies, unusual pos-
turing,
object stereotypies,
and
self-injurious behaviors
(SIBs) should
be
routinely documented through parental
report
or
observation. Hand
or
finger
mannerisms, body
rocking,
and
other motor disturbances such
as
unusual
posturing,
are
commonly reported
in
37-95%
of
subjects
studied (Adrien, Ornitz, Barthelemy, Sauvage,
&
Lelord,
1987; Elliott, 1990;
Le
Couteur
et
al., 1989; Ornitz,
Guthrie,
&
Farley, 1977),
and
often
manifest during
the
preschool years (Lord, 1995).
The
development
of
stereo-
typies, particularly
in
severe forms (e.g., SIB),
may
pro-
foundly
influence individual outcomes
and
prognosis
for
treatment
in
children with autism.
Sensory processing abilities
are
also prominently
aberrant
in
autism. Preoccupations with sensory features
of
objects, sensory modulation difficulties reflected
in
over-
and
underresponsiveness
to
environmental stimuli,
and
paradoxical responses
to
sensory stimuli, among oth-
ers, have been reported
in
42-88%
of
persons with autism
studied (Elliott, 1990; Kientz
&
Dunn, 1997;
Le
Couteur
et
al., 1989). Sensory processing requires assessment
by
expert clinical observations
in
tandem with parent reports
or
questionnaires because these disruptions
may
impact
strongly
on
performance
in
daily activities.
The
Sensory Integration
and
Praxis Tests (Ayres,
1989)
are not
routinely warranted
as
part
of
diagnostic
evaluations
of
children with autism. However, this bat-
tery
of
tests
may be
prescribed
on an
individual basis
to
detect specific patterns
of
sensory integrative dys-
function
in
children between
the
ages
of 4 and 9
years
with
average cognitive functioning.
Occupational
Therapy
Evaluation.
The
occupa-
tional therapist,
as
part
of the
evaluation team, should
make
a
determination about
the
necessity
to
screen
and
fully
evaluate
an
individual with autism about whom
there
are
concerns regarding
functional
skills
or
occu-
pational performance (i.e., goal-directed everyday rou-
tines).
It is
important that
the
occupational therapist have
a
comprehensive understanding
of
autism
and be
expe-
rienced
in
assessing persons
in the age
range
of the
clients
being seen (e.g., child
vs.
adult).
The
occupational ther-
apist
first
and
foremost evaluates performance specifi-
cally
in the
areas
of
play
or
leisure, self-maintenance
through activities
of
daily living,
and
productive school
or
work activities. Play
is
often
disrupted
in
young chil-
dren with autism (Restall
&
Magill-Evans, 1994; Stone
&
Lemanek, 1990)
and
particularly warrants assessment
in
a
naturalistic context. Second,
the
occupational ther-
apist should consider
any
specific performance compo-
nents
or
contexts that
may be
impacting
on the
individ-
ual's
daily
functioning
because this information
is
critical
to the
team diagnostic process
as
well
as to an
appropri-

466
Filipek
et al.
ate
individualized intervention plan. Among specific
components noted
to be
problematic,
but not
necessarily
specific,
to
persons with autism,
are
complex motor
planning
abilities (Mailloux, Parham,
&
Roley, 1998;
Minshew
et
al., 1997), sensory processing abilities
(Adrien
et
al., 1993; Baranek, 1999; Dahlgren
&
Gill-
berg, 1989; Kientz
&
Dunn, 1997; Ornitz
et
al., 1977),
imitation skills (Rogers
et
al., 1996; Stone
&
Lemanek,
1990), social
and
interpersonal skills (Gillberg
et
al.,
1990; Stone
&
Hogan, 1993; Volkmar
et
al., 1993a),
and
coping with behavioral rigidities
or
restricted interests
(Baranek,
Foster,
&
Berkson, 1997). Supplemental
in-
terviews
and
parental reports should
be
used
to
corrob-
orate
observational
findings
or
standardized
assessments,
particularly
if
those assessments were performed outside
of
the
individual's typical routines
and
environments.
Neuropsychological, Behavioral,
and
Academic
Assessment
Psychologists trained
in
evaluating autistic individ-
uals
can
play
a
critical
role
in
intervention planning, out-
come assessment,
and the
diagnosis
and
treatment
of co-
morbid
psychological conditions. Standardized measures
are
used
to
establish baseline
function
in
many domains
of
learning, performance,
and
socialization. Behavioral
assessment
by
direct observation
is
used
to
address spe-
cific
learning
and
behavior problems,
to
establish
the
functional
or
controlling relations
of
inappropriate
be-
havior,
to
track behavioral
progress,
and to
document
the
effectiveness
of
intervention. These
are
specialized psy-
chological
services,
requiring appropriate training
and
experience. Specific assessments
may
address
a
child's
psychological profile, motivation
or
reinforcement pref-
erences, learning style, sensory
and
motor characteristics
(and
associated
abnormalities), specific social skills
deficits,
academic skills, ritualistic
or
stereotyped pat-
terns
of
behavior,
and
life-style
and
family
relationships.
Recent
research
suggests that specific neuropsy-
chological impairments
can be
identified
in
children
in
early childhood
and
that such impairments
are
correlated
with
the
severity
of
autistic symptoms (Dawson, 1996;
Dawson, Meltzoff, Osterling,
&
Rinaldi, 1998). Among
the
diverse types
of
neuropsychological impairments that
may
be
exhibited
by
children with autism
are
deficits
in
explicit memory,
in
establishing rules governing reward
contingencies,
and in
working memory, planning,
and
response inhibition (Dawson, 1996). Thus,
it can be
use-
ful
to
assess
a
range
of
neuropsychological functions,
in-
cluding
attention, memory, praxis, language
and
visual-
spatial processing,
so
that educational strategies
can
address each child's specific strengths
and
weaknesses.
Assessment
of
Family Functioning
and
Resources
The
family
is a
child's best resource. Parental
in-
tervention
and
behavior management strategies provided
by
a
psychologist have
a
strong impact
on the
child's
de-
velopmental status
and
autistic symptoms. Parental stress
and
exhaustion
can
adversely
affect
the
child's well-
being. Thus evaluation
of the
child must take
place
within
the
context
of his or her
family.
One
must deter-
mine
the
parents' level
of
understanding
of
their child's
condition
and
offer
appropriate counseling
and
educa-
tion.
One
must determine
if the
family
has
informal sup-
ports, such
as
extended
family,
neighbors,
or
friends
to
assist them
in
their child-rearing responsibilities.
The
family's
readiness
to
meet other families
of
children with
similar
conditions must also
be
assessed. Often families
learn
more
and
communicate more
with
other families
than
they
do
with professionals. Finally, based
on the
family's
socioeconomic status
and the
status
of the
child,
one
must evaluate
the
need
for and
availability
of
vari-
ous
social services
to
provide respite
and
other supports.
Social workers, psychologists,
or
other profession-
als
who
specialize
in
families
of
autistic individuals
may
be
best able
to
assess
the
family
dynamics
in
relation
to
parenting
and
behavior management strategies
as
they
specifically
relate
to the
autistic child. These profes-
sionals
may
also know additional resources specifically
tailored
to
families
of
autistic individuals. Finally, they
themselves
may
facilitate parent support groups
and
plan
parent seminars. This assessment will focus
on the
specific
issues relating
to the
type
of
developmental pro-
file
identified during
the
Level
2
evaluation.
It
cannot
be
overemphasized that
the
family
is the
child's
best
re-
source. Although there
may be
several confounding vari-
ables
affecting
a
child's
overall adult outcome, most
autism
specialists would agree that
the
family
does play
a
very important
role.
This expanded assessment
can
also
help determine
the
quality
and
quantity
of
community
resources, educational programs
and
networking that
a
particular
family
needs. Each
family
is
unique
in its
search
for
support
and
knowledge.
Level
2
Laboratory Investigation
Metabolic Testing
A
wide range
of
biochemical determinations have
been performed
in
urine, blood,
and
cerebrospinal
fluid
in
an
attempt
to
identify
a
specific metabolic abnormal-
ity
in
individuals
with
autism. Included
are
studies
of in-
born
errors
in
amino acid, carbohydrate, purine, peptide,
and
mitochondrial metabolism,
as
well
as
toxicological

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
467
studies.
The
reported co-occurrence
of
autistic-like
symptoms
in
individuals with inborn errors
of
metab-
olism
has led to
consideration
of
screening tests
as
part
of the
routine assessment
of
patients with severe
de-
velopmental impairment
(Steffenburg,
1991). However,
the
percentage
of
children with autism
who
prove
to
have
an
identifiable metabolic disorder
is
probably less
than
5%
(Dykens
&
Volkmar, 1997; Rutter, Bailey,
Bolton,
& Le
Couteur, 1994; Rutter
et
al., 1997). Most
of
the
biochemical analyses
are
useful
at
present only
as
research tools
in the
ongoing
effort
to
understand
the
biology
of
autism.
Metabolic testing
or
consultation
is
indicated
by a
history
of
lethargy,
cyclic
vomiting,
early
seizures,
dys-
morphic
or
coarse
features, mental retardation
or if
men-
tal
retardation cannot
be
excluded, questionable new-
born screening,
or
birth
out of the US
because
of the
potential
absence
of
newborn screening
and
maternal
public health measures.
As
recommended
by the
Amer-
ican
College
of
Medical Genetics, selective metabolic
testing should
be
initiated only
in the
presence
of
sug-
gestive clinical
and
physical
findings
(Curry
et
al., 1997).
Genetic Testing
Of
the
chromosomal disorders
found
in
associa-
tion
with
autism,
the
most
common abnormality
de-
scribed
in
recent studies
is
that involving
the
proximal
long
arm of
chromosome
15
(15ql
l-q13),
occurring
in
1 to 4% of
consecutive
cases
meeting criteria
for
Autis-
tic
Disorder (Cook
et
al., 1998; Gillberg, 1998). These
are
usually maternally inherited duplications, either
pseudodicentric
15
(inverted duplication
15) or
other
atypical marker chromosomes, with
one or two
extra
copies
of the
area
roughly corresponding
to the
typical
Angelman
syndrome (AS)/Prader Willi syndrome
(PWS)
deletion
region
of
approximately
4
million base
pairs.
The 15q
patients typically have moderate
to
pro-
found
mental retardation.
In
samples
of
patients with
autistic disorder whose
IQ was
greater
than
35,
inter-
stitial
duplications
of
15q11-13
have been found
in
more
than
1% of
patients
and at a
greater frequency
than fragile
X or
other currently identifiable chromo-
somal disorders (Cook
et
al., 1998; Gillberg, 1998; Per-
icak-Vance
et
al., 1997; Schroer
et
al., 1998; Weidmer-
Mikhail, Sheldon,
&
Ghaziuddin, 1998).
Angelman syndrome, usually
due to an
absence
(deletion)
of
maternally inherited
15q11-q13
material,
has
been found
in
patients
with
autism
and
profound men-
tal
retardation (Gillberg, 1998; Schroer
et
al., 1998; Stef-
fenburg,
Gillberg, Steffenburg,
&
Kyllerman, 1996).
Autism
has
also been
found
in
patients
with
PWS
(Demb
&
Papola, 1995), although
at a
decreased rate relative
to
the
frequency
of
autism
in
Angelman syndrome
or du-
plications
of
15ql 1-13.
Confirmation
by
FISH probes
for
the
PWS/AS region
is
necessary
to
confirm
cytogenetic
evidence
of
15q11-13
abnormalities.
DNA
analysis
for
fragile
X and
high resolution chro-
mosome studies (karyotype)
are
indicated
for a
diagno-
sis of
autism, mental retardation
(or if
mental retardation
cannot
be
ruled out),
if
there
is a
family
history
of
frag-
ile X or
undiagnosed mental retardation,
or if
dysmor-
phic features
are
present (American College
of
Medical
Genetics: Policy Statement,
1994).
It
should
be
under-
stood, however, that there
is
little likelihood
of
positive
karyotype
or
fragile
X
testing
in the
presence
of
high-
functioning
autism.
The
absence
of a
positive genetic test
does
not
exclude
a
genetic basis
for
autism.
If the
indi-
cations
for DNA
analysis
for
fragile
X and
high resolu-
tion
chromosome studies
are
present
but the
family
de-
clines genetic testing,
the
family
should
be
counseled
to
inform
extended
family
members
of the
potential gene-
tic
risks
of
this disorder
so
they
may
seek appropriate
genetic counseling.
In
addition,
the
recurrence risk
of
autism
is
esti-
mated
to be
between
3 and 7%
across several studies
(Bolton
et
al., 1994;
Jorde
et
al., 1990; Piven
et
al., 1990;
Szatmari
et
al., 1993).Therefore, although there
is no
current method
to
detect
autism
prenatally,
parents
should
be
counseled about
the
almost 50-fold increased
risk
of
having
a
second child
on the
autistic spectrum
(1 in 20 to 1 in 10, as
compared
with
1 in
1,000
to 1 in
500 for the
general population).
Electrophysiologic Testing
The
prevalence
of
epilepsy
in a
large cohort
of
pre-
school children with autism
has
been estimated
as 7%
(Rapin,
1996a),
in
another cohort,
14%
(Tuchman
et
al.,
1991b),
and the
cumulative prevalence
by
adulthood
is
estimated
at 20 to 35%
(Minshew
et
al., 1997).
The
peaks
of
seizure onset occurred
in
early childhood
and
again
in
adolescence (Gillberg
&
Steffenburg,
1987; Lockyer
&
Rutter, 1970; Minshew
et
al., 1997; Rossi, Parmeggiani,
Bach, Santucci,
&
Visconti, 1995; Volkmar
&
Nelson,
1990; Wong, 1993). Mental retardation,
with
or
without
motor abnormalities
and
family
history
of
epilepsy,
was
a
significant risk factor
for the
development
of
seizures
in
autistic individuals.
The
relationship between autism
with
an
early regressive course (before
36
months),
CDD
(after
36
months),
Landau-Kleffner
syndrome (Landau
&
Kleffner,
1957, 1998),
and
electrical status epilepti-
cus
during slow wave sleep (ESES)
is
currently poorly
understood,
as are
their
underlying
etiologies
and
patho-

468
Filipek
et al.
physiologies (Bristol
et
al., 1996; Tuchman
&
Rapin,
1997). Regression
in
adolescence associated with seizure
onset
has
also
been
reported,
with
further
loss
of
lan-
guage
and
cognitive skills (Lockyer
&
Rutter,
1970),
but
little
is
known about
its
cause
or
prevalence (Minshew
et
al., 1997).
Seizures
may be of all
types,
but
partial complex
seizures
seem
to be
more prevalent, with
EEG
abnor-
malities occurring most often over
the
temporal
lobes
(Olsson
et
al., 1988).
The
recognition
of
complex par-
tial seizures
in
autistic individuals
is
complicated
by
the
tendency
to
blame unusual behaviors
on
autism,
and
by
the
lack
of
direct correlation between clinical
seizures
and EEG
paroxysmal activity (Minshew
et
al.,
1997).
In
addition,
a
recent study
suggests
that there
may
be a
casual relationship between
a
subgroup
of
children
with autistic regression
and
EEG-defined "be-
nign
focal
epilepsies"
(Nass, Gross,
&
Devinsky, 1998).
Any
behaviors such
as
staring, cessation
of
activity,
or
aggressive
escalations
associated
with confusion should
trigger
a
high index
of
suspicion
of
complex partial
seizures
in
autistic individuals.
Indications
for a
prolonged sleep-deprived
EEG
with adequate sampling
of
slow wave
sleep
include
evidence
of
clinical seizures, history
of
regression (clin-
ically significant
loss
of
social
and
communicative
func-
tion)
at any age but
especially
in
toddlers
and
pre-
schoolers,
and in
situations where there
is a
high index
of
clinical suspicion that epilepsy, clinical
or
subclini-
cal,
may be
present.
There
is
inadequate evidence
at the
present time
to
recommend
EEG
studies
in all
individ-
uals with autism (Rapin, 1995, 1997; Rossi
et
al., 1995;
Tuchman,
Jayakar, Yaylali,
&
Villalobos, 1997; Tuch-
man, 1994, 1995; Tuchman
&
Rapin, 1997; Tuchman
et
al., 1991b.)
Except
for the
specific tests noted earlier, event-
related potentials (Ciesielski, Knight, Prince, Harris,
&
Handmaker, 1995; Kemner, Verbaten, Cuperus, Cam-
fferman,
& Van
Engeland, 1994; Kemner, Verbaten,
Cu-
perus, Camfferman,
& van
Engeland, 1995; Lincoln,
Courchesne, Harms,
&
Allen,
1995b;
Rapin
&
Dunn,
1997; Verbaten, Roelofs,
van
Engeland, Kenemans,
&
Slangen, 1991)
and
magnetoencephalography (Chuang,
Otsubo, Hwang, Orrison,
&
Lewine, 1995; Morrell
et
al.,
1995; Salmelin, Service, Kiesila, Uutela,
&
Salonen,
1996)
are
considered
to be
research tools
in the
evaluation
of
autism, without evidence
of
routine clinical
utility
at
present.
Neuroimaging
Computed tomographic (CT) studies during
the
1970s
and
1980s reported
a
wide range
of
brain imaging
abnormalities, which contributed
to the
then prevalent
view that most cases
of
autism would ultimately
be
found
to be
attributable
to an
underlying structural dis-
order. This perspective
of
autism,
together
with
the
gen-
eral clinical practice
in
child neurology
of
including
CT
scanning
in the
search
for
etiologies
of
unexplained
de-
velopmental delay
in
young children,
led to the
stan-
dardization
of CT as
part
of the
assessment
of
children
diagnosed
with autism during
the
1970s
and
1980s.
This
perspective changed substantially
as a
result
of the
landmark
study
of
Damasio
et al.
(1980) demonstrating
that
CT
abnormalities
of the
brain
in
autistic individu-
als
were associated only with
the
presence
of
coexist-
ing
disorders rather than with autism itself.
In a
review
of
over
400
imaging studies
in
autistic subjects,
a
very
low
prevalence
of
focal lesions
or
other abnormalities
was
reported,
and
their inconsistent localization marked
them
as
coincidental (Filipek
et
al., 1992a).
In a
subse-
quent
study,
the
prevalence
of
lesions
on MRI in the
children with autism
was
equal
to
that
in the
normal
control volunteers (Filipek
et
al., 1992b).
A
series
of
CT and
magnetic resonance imaging (MRI) studies
of
autistic subjects screened
to
exclude those with identi-
fiable
disorders other than autism (see reviews
by
Min-
shew
et
al., 1994, 1996b, Filipek
et
al., 1992a, 1996,
1999) have confirmed
the
absence
of
significant
de-
tectable brain abnormalities characteristic
of
autism.
The
clinical perception that structural brain imaging
should
be
routinely included
in the
assessment
to
iden-
tify
gross brain abnormalities causing autism
is,
there-
fore,
no
longer viewed
as
valid (Filipek, 1999).
Functional imaging studies
are a
research
endeavor
in
autism
and do not
have
a
role
in
clinical diagnosis
at
the
present time. With
the
advent
of
functional imaging
methods, such
as
functional
MRI
(fMRI),
single photon
emission tomography (SPECT),
and
positron emission
tomography (PET), such studies
are
expected
to
play
a
major
role
in
defining
the
brain basis
for the
behavioral
impairments
in
autism,
but as
research
tools only.
The
value
of
such studies will depend heavily
on the
design
of
activation paradigms,
the
documentation
of the
task
demands
of the
paradigms
for the
individual,
and the in-
terpretation
of the
findings within
the
broader
context
of
what
is
known about neurobehavioral
function
in
autism.
One
construct
of
growing value
in
this regard
is the
cog-
nitive
model
of
autism
as a
selective disorder
of
complex
information-processing
abilities
and as a
disorder
of
mul-
tiple
primary
deficits
(Minshew
&
Goldstein, 1998).
The
presence
of
neurologic features
not
explained
simply
by the
diagnosis
of
autism (e.g., asymmetric
motor examination, cranial nerve
dysfunction,
severe
headache)
may be an
indication
for
imaging,
in
which
case
the
usual standards
of
practice apply (Filipek, 1999).

Screening
and
Diagnosis
of
Autistic Spectrum
Disorders
469
Autism
per se is not
considered
an
indication
for
neuro-
imaging, even
in the
presence
of
megalencephaly.
Tests
of
Unproven
Value
There
is
inadequate evidence
to
support routine
clinical
testing
of
individuals
with
autism
for
hair analy-
sis for
trace elements (Gentile, Trentalange, Zamichek,
&
Coleman, 1983; Shearer, Larson, Neuschwander,
&
Gedney, 1982;
Wecker,
Miller, Cochran, Dugger,
&
Johnson,
1985),
celiac
antibodies
(Pavone, Fiumara, Bot-
taro, Mazzone,
&
Coleman, 1997), allergy testing
(in
particular food
allergies
for
gluten, casein,
Candida
and
other molds) (Lucarelli
et
al., 1995), immunological
or
neurochemical abnormalities (Cook, Perry, Dawson,
Wainwright,
&
Leventhal, 1993; Singh, Warren, Averett,
&
Ghaziuddin, 1997; Yuwiler
et
al., 1992), micronutri-
ents such
as
vitamin
levels
(Findling
et
al., 1997;
LaPer-
chia, 1987;
Tolbert,
Haigler, Waits,
&
Dennis, 1993),
intestinal permeability studies (D'Eufemia
et
al., 1996),
stool analysis, urinary peptides
(Le
Couteur, Trygstad,
Evered, Gillberg,
&
Rutter, 1998), mitochondrial dis-
orders (including lactate
and
pyruvate) (Lombard, 1998),
thyroid
function
tests
(D. J.
Cohen, Young, Lowe,
&
Harcherik, 1980; Hashimoto
et
al.,
1991),
or
erythrocyte
glutathione
peroxidase studies (Michelson, 1998).
Referral
to
Early
Intervention
Again,
the
Level
2
clinicians should
refer
to an ap-
propriate
early intervention
or
school team
if the
Level
1
clinicians
did not do so. If the
child
is,
indeed,
en-
rolled
in a
program,
the
results
of
Level
2
evaluations
by
the
psychologist, speech
and
occupational therapists
should
be
communicated
to the
staff
in an
effort
to
bet-
ter
tailor their intervention strategies
to the
particular
needs
of the
child.
RECOMMENDATIONS
Level
1:
Routine Developmental
Screening
1.
All
professionals involved
in
early child care
(pediatricians, neurologists, psychiatrists, psycholo-
gists, audiologists, language pathologists, physical ther-
apists,
and
occupational therapists) should
be
suffi-
ciently familiar with
the
signs
and
symptoms
of
autism
to
recognize possible social, communicative,
and be-
havioral indicators
of the
need
for
further
diagnostic
evaluation.
2.
Developmental screening should
be
performed
at
each
and
every well-child visit throughout
infancy,
toddlerhood,
the
preschool years,
and at any age
there-
after
if
concerns
are
raised about social acceptance, learn-
ing
and
behavior. Recommended screening tools include
The
Ages
and
Stages Questionnaire
(ASQ),
The
BRIG-
ANCE®
Screens,
The
Child Development Inventories
(CDIs),
and the
Parents' Evaluation
of
Developmental
Status
(PEDS).
Also recommended
is the use of
Specific
Developmental Probes,
as
outlined
in the
text,
to
specif-
ically
identify
any
parental concerns about development.
The
Denver-H (formerly
the
Denver Developmental
Screening
Test-Revised)
is not
recommended
as an ap-
propriate developmental screen
in
this capacity.
3. The
following developmental milestones
are
nearly
universally present
by the age
indicated. Failure
to
meet
any of
these milestones
is an
absolute indication
to
proceed with
further
evaluations. Delay
in
referral
for
such
testing
may
delay early diagnosis
and
treatment
and
affect
the
long-term outcome.
No
babbling
by 12
months.
No
gesturing (pointing,
waving
bye-bye, etc)
by
12
months.
No
single words
by 16
months.
No
2-word spontaneous (not
just
echolalic)
phrases
by 24
months.
Any
loss
of any
language
or
social skills
at any
age.
4.
Level
1
Laboratory Investigations. Concern
re-
garding
a
speech, language,
or
hearing problem
by
par-
ent
or
practitioner should prompt
an
immediate referral
for
a
formal audiologic assessment, regardless
of
whether
the
child
"passed"
a
neonatal hearing
screen.
Audiological assessment should
be
performed
at
centers with qualified
and
experienced pediatric audi-
ologists, with current audiological testing methods
and
technologies. Facilities without these qualifications
should enter consortial arrangements with centers that
are
able
to
provide this type
of
comprehensive
assess-
ment
of
children with autism.
Periodic
lead
screens
should
be
performed
in any
autistic child with pica.
5.
Professionals involved
in
early child care should
also become familiar
with
and use one of the
screening
instruments
for
children with autism (e.g.,
the
Checklist
for
Autism
in
Toddlers
(CHAT),
the
Pervasive Devel-
opmental
Disorders Screening
Test
(PDDST),
or, for
older verbal children,
the
Australian
Scale
for
Asperger's
Syndrome).
6. The
social, communication
and
play develop-
ment
and
behavior
of
siblings
of
children
with
autism
needs
to be
monitored very
carefully
not
only
for
autism-
related symptoms
but
also
for
language delays, learning
difficulties,
and
anxiety
or
depressive symptoms.
7. As
mandated
by
Public
Law
99-457,
and re-
authorized
as
Public
Law
105-17: Individuals
with
Dis-
abilities Education Act- IDEA (1997),
a
referral
for

470
Filipek
et al.
early intervention should
be
initiated
by the
primary care
practitioner. Children
less
than
36
months
of age
should
be
referred
to the
zero-to-three service system
in
their
community;
children ages
36
months
and
older should
be
referred
to the
local school district.
8.
Health care providers
and
others need
to
increase
their comfort level
in
talking with families about autism,
which
is a
treatable disorder with
a
wide range
of
out-
comes. Thus, information about
the
benefits
of
early
in-
tervention
for
children with autism needs
to be
widely
disseminated
to
health
care
professionals
and
others
working
with young children
and
families.
9.
Screening tools
for
older children with milder
symptoms
of
autism
need
to be
made
widely
available
in
educational
and
recreational settings, where these
children's difficulties
are
often most visible,
as
well
as
in
health
and
allied health settings. Pediatricians
can
and
should play
an
important
role
in
raising
a
suspi-
cion
of
autism, paving
the way to
appropriate referral
to
professionals knowledgeable about autism
in
verbal
individuals.
Level
2:
Diagnosis
and
Evaluation
of
Autism
1.
It is the
consensus
of
this Panel that Level
2
Diagnosis
and
Evaluation should
be
performed
by
pro-
fessionals
who
specialize
in the
treatment
of
children
with
autism.
2.
The
diagnosis
of
autism should
be
accurately
made based
on
clinical
and
DSM-IV criteria,
and
should
include
the use of a
diagnostic instrument with
at
least
moderate sensitivity
and
good specificity
for
autism.
Sufficient
time must
be
planned
for
both
a
stan-
dardized parent interview regarding current concerns
and
behavioral history
related
to
autism,
and
direct,
structured
observation
of
social
and
communicative
be-
havior
and
play.
Such interview instruments include
the
Gilliam
Autism Rating Scale (GARS),
The
Parent Interview
for
Autism
(PIA),
The
Pervasive Developmental Disorders
Screening
Test-
Stage
2
(PDDST),
or the
Autism
Diag-
nostic Interview-Revised (ADI-R).
Direct, structured observation instruments include
the
Screening
Tool
for
Autism
in
Two-Year-Olds (STAT),
the
Childhood
Autism
Rating Scale (CARS),
and the
Autism
Diagnostic
Observation
Schedule-Generic
(ADOS-G).
3.
Individuals with even mild autism must also
re-
ceive adequate assessments
and
appropriate diagnoses,
using
practice
standards similar
to
those outlined above.
4.
Diagnostic evaluations must also address those
factors
that
are not
specific
to
autism, including degree
of
language impairment, mental handicap,
and
presence
of
nonspecific behavioral disorders such
as
overactivity,
aggression, anxiety, depression,
or
specific learning dis-
abilities, which
can
significantly
affect
outcome
and
treatment
of
autistic individuals.
5. An
expanded medical
and
neurological evalua-
tion
whose
focus
is on the
search
for
acquired brain
in-
jury,
comorbid condition,
or
difficulties common
in
autism:
pregnancy, delivery, perinatal history,
develop-
mental history including milestones,
regression
in
early
childhood
or
later
in
life, encephalopathic events, atten-
tion
deficit disorder, seizure disorder (absence
or
gen-
eralized), depression
or
mania, troublesome behaviors
such
as
irritability,
self-injury,
sleep
and
eating
distur-
bances,
and
pica
for
possible lead exposure.
Family History should specifically probe
in
nuclear
and
extended
family
for
autism, mental retardation,
frag-
ile
X
syndrome,
and
tuberous sclerosis complex, because
of
their implications regarding
the
need
for
chromoso-
mal
or
genetic evaluation.
In
addition, family members
with
affective
or
anxiety disorder should
be
identified,
as
these
impact
on the
care
of the
child
and
family
bur-
den.
The
focus
of the
physical
and
neurological exami-
nation should include: longitudinal measurements
of
head circumference, unusual features (facial, limb,
stature, etc.) suggesting
the
need
for
genetic evaluation,
neurocutaneous abnormalities (requiring
an
ultraviolet
Wood's-lamp examination), gait, tone, reflexes, cranial
nerves,
and
mental status including verbal
and
nonverbal
language
and
play.
6. A
speech-language-communication
evaluation
should
be
performed
on all
children
who
fail
language
developmental screening procedures,
by a
language
pathologist
with
training
and
expertise
in
evaluating chil-
dren
with autism.
A
variety
of
strategies
should
be
used
in
this
as-
sessment, including
but not
limited
to
direct standard-
ized instruments, naturalistic observation, parental
in-
terviews,
and
procedures focusing
on
social-pragmatic
abilities.
Results
of a
speech-language-communication
assessment should always
be
interpreted relative
to a
child's cognitive, motor
and
socioemotional abilities.
7. A
cognitive evaluation should
be
performed
in
all
children with autism
by a
psychologist
or
develop-
mental
pediatrician experienced
in
autism testing,
and
should
include assessment
of
family
(parent
and
sib-
ling)
strengths, talents, stressors,
and
adaptation,
as
well
as
resources
and
supports. Psychologists working
with
children with autism should
be
familiar with
a
range
of
theories
and
approaches specific
to
this pop-
ulation.

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
471
Psychological instruments should
be
appropriate
for
the
mental
and
chronological age, should provide
a
full
range
(in the
lower direction)
of
standard
scores,
in-
cluding independently
scored
measures
of
verbal
and
nonverbal
abilities, should provide
an
overall index
of
ability,
and
should have current norms
which
are
inde-
pendent
of
social ability.
8.
A
measure
of
adaptive
functioning
should
be
col-
lected
by the
psychologist
for any
child evaluated
for an
associated
mental handicap. Recommended instruments
include
the
Vineland
Adaptive Behavior Scales
and the
Scales
of
Independent
Behavior-Revised (SIB-R).
9.
Screening
and
full
evaluation
for
sensorimotor
skills
by
qualified professionals
(occupational
thera-
pists
or
physical therapists)
with
expertise
in
testing
persons with autism should
be
considered, including
an
assessment
of
gross
and
fine
motor skills, praxis, sen-
sory processing abilities, unusual
or
stereotyped man-
nerisms,
and the
impact
of
these components
on the
autistic person's
life.
10. An
occupational therapy evaluation
is
indicated
when
an
autistic individual
is
experiencing disruptions
in
functional
skills
or
occupational performance
in the
areas
of
play
or
leisure, self-maintenance through activ-
ities
of
daily living,
or
productive school
and
work tasks.
The
occupational therapist
may
evaluate
these
per-
formance areas
in the
context
of
different
environments,
and
through activity analysis,
the
contributions
of
per-
formance component abilities (e.g., sensory processing,
fine
motor skills, social skills)
in
goal-directed everyday
routines.
11.
A
neuropsychological, behavioral,
and
aca-
demic assessment should
be
performed,
in
addition
to
the
cognitive assessment,
to
include communication
skills,
social
skills
and
relationships, educational
func-
tioning, problematic behaviors, learning style, moti-
vation
and
reinforcement, sensory
functioning,
and
self-regulation.
12.
Assessment
of
family
functioning should
be
performed
to
determine
the
parents' level
of
under-
standing
of
their
child's
condition
and
offer
appropriate
counseling
and
education. Based
on the
family's
socio-
economic status
and the
status
of the
child,
one
must
evaluate
the
need
for and
availability
of
various social
services
to
provide respite
and
other supports.
13.
Assessment
of
family resources should
be
per-
formed
by
social workers, psychologists,
or
other pro-
fessionals
who
specialize
in
families
of
autistic indi-
viduals,
who may be
better able
to
assess
the
family
dynamics
in
relation
to
parenting
and
behavior man-
agement strategies
as
they specifically relate
to the
autistic child.
14.
Level
2
Laboratory Evaluation
may
include
the
following,
as
indicated:
(a). Metabolic testing
or
consultation
is
indicated
by
a
history
of
lethargy, cyclic vomiting, early seizures;
dysmorphic
or
coarse features; mental retardation
or if
mental retardation cannot
be
excluded;
if
there
is any
question concerning
the
occurrence
or
adequacy
of
new-
born screening
for a
birth
within
the US; or
birth
out of
the
U.S. indicating
the
potential absence
of
newborn
screening
and
maternal public health measures.
As
recommended
by the
American
College
of
Medical Genetics, selective metabolic testing should
be
initiated
by the
presence
of
suggestive clinical
and
physical
findings.
(b). Genetic testing, specifically
DNA
analysis
for
fragile
X and
high resolution chromosome studies (kary-
otype),
are
indicated
for a
diagnosis
of
autism, mental
retardation
(or if
mental retardation cannot
be
excluded),
if
there
is a
family
history
of
fragile
X or
undiagnosed
mental
retardation,
or if
dysmorphic features
are
pres-
ent.
It
should
be
understood, however, that there
is
lit-
tle
likelihood
of
positive karyotype
or
fragile
X
testing
is
the
presence
of
high-functioning
autism.
If
a
family
declines genetic testing, they should
be
counseled
to
inform
extended
family
members
of the
potential genetic risks
of
this disorder
so
they
may
seek
appropriate genetic counseling.
Although
there
is no
current method
to
detect
autism prenatally, parents
of
children with autism should
be
counseled
to
inform
them
of the
50-fold increased
risk
of
having
another autistic child
(1 in 10 to 1 in 20,
as
compared
with
1 in 500 in the
general population).
(c). Indications
for a
prolonged sleep-deprived
EEG
with adequate sampling
of
slow wave sleep include
evidence
of
clinical seizures, history
of
regression
(clinically significant
loss
of
social
and
communica-
tive
function)
at any age but
especially
in
toddlers
and
preschoolers,
and in
situations where
there
is a
high
index
of
clinical suspicion that epilepsy, clinical
or
subclinical,
may be
present.
There
is
inadequate evi-
dence
at the
present time
to
recommend
EEG
studies
in
all
individuals with autism.
Other event-related potentials
and
magneto-
encephalography
are
considered research tools
in the
evaluation
of
autism
at the
present time, without evi-
dence
of
routine clinical utility.
(d). Neuroimaging
may be
indicated
by the
pres-
ence
of
neurologic features
not
explained
by the
diag-
nosis
of
autism
(e.g.,
asymmetric motor examination,
cranial nerve
dysfunction,
severe headache),
in
which
case
the
usual standards
of
practice apply. Routine
clinical neuroimaging does
not
have
any
role
in the

472
Filipek
et al.
diagnostic evaluation
of
autism
at the
present time,
even
in the
presence
of
autistic megalencephaly.
Functional imaging modalities
(fMRI,
SPECT,
and
PET)
at
present
are
considered solely
as
research tools
in
the
evaluation
of
autism.
(e). Tests
of
unproven value: There
is
inadequate
evidence
to
support routine clinical testing
of
individu-
als
with
autism
for
hair analysis
for
trace elements, celiac
antibodies, allergy testing
(in
particular
food
allergies
for
gluten, casein,
Candida
and
other molds), immuno-
logical
or
neurochemical abnormalities, micronutrients
such
as
vitamin levels, intestinal permeability studies,
stool analysis, urinary peptides, mitochondrial disorders
(including
lactate
and
pyruvate), thyroid
function
tests,
or
erythrocyte glutathione peroxidase studies.
15.
Reevaluation
at
least within
a
year
of
initial
di-
agnosis
and
continued monitoring
is an
expected aspect
of
clinical
practice,
because relatively small changes
in
developmental level
affect
the
impact
of
autism
in the
preschool years.
16. It is the
consensus
of
this Panel that
the
role
of
medical professionals
can no
longer
be
limited
to
simply
the
diagnosis
of
autism. Professionals must expand their
knowledge
and
involvement
to be
better able
to
counsel
families
concerning available
and
appropriate treatment
modalities, whether educational, empirical,
or
"just
off
the
web."
In
addition, professionals must
be
familiar with
federal
law
which mandates
a
free
and
appropriate edu-
cation
for all
children
from
the age of 36
months,
and in
some
states,
from
zero
to
three
as
well.
Other
Recommendations
1.
Existing managed-care policy must change
as
follows:
Extremely brief well-child visits must increase
in
duration,
with appropriate compensation,
to
permit
the
implementation
of
routine developmental screening
as
recommended above.
Short specialty visits must also increase
in
dura-
tion, with appropriate compensation,
to
permit
the use
of
appropriate diagnostic instruments,
as
recommended
above.
Autism
must
be
recognized
as a
medical disorder,
and
managed
care
policy must
cease
to
deny appropri-
ate
medical
or
other therapeutic
care
under
the
rubric
of
"developmental
delay"
or
"mental health condition."
2.
Existing governmental agencies that provide
services
for
individuals with developmental disabilities
must
also change their eligibility criteria
to
include
all
individuals
on the
autistic spectrum, whether
or not the
relatively narrow criteria
for
Autistic Disorder
are
met,
who
nonetheless must
also
receive
the
same adequate
assessments, appropriate diagnoses,
and
treatment
op-
tions
as do
those with
the
formal diagnosis
of
Autistic
Disorder.
3.
Public awareness
and
dissemination activities
re-
garding
the
signs
and
symptoms
of
autism must occur
throughout
communities,
to
provide information
to
par-
ents,
child-care workers, health-care settings,
and
com-
munity
centers. Small, attractive fliers targeting symp-
toms,
needs,
and
outcomes
of
very young children
and
also
older children should
be
developed
and
disseminated
widely,
in
collaboration with
the
national autism
soci-
eties
and
associations, schools, health,
and
allied health
agencies which need
to
join
in
this concerted
effort.
4.
Increased education
of
health-related
and
education-related professionals about autism must occur
at
the
preservice level. Professionals must learn
to
pro-
vide
more than
a
diagnosis
and a
telephone number
for
governmental
services
to
parents. Trainees
in
general
and
developmental pediatrics, psychiatry, neurology,
early childhood education, speech
and
language pathol-
ogy, occupational therapy, physical therapy, psychology,
nursing,
child-care providers, public health, education,
and
other disciplines need markedly increased knowl-
edge about
the
range
of
symptoms
of
autism both early
and
later
in
life,
about
the
educational
and
community
needs
of
autistic individuals,
and the
potential outcomes
of
autism. They must also learn
how to
discuss potential
risks
of
autism with families.
AN
ANALYSIS
OF
DIFFERENCES RELATIVE
TO
OTHER PRACTICE PARAMETERS
This consensus recommendation parallels
and ex-
pands
upon many
of the
major
points
of the
Cure Autism
Now
(CAN) Consensus Statement (CCS; Geschwind,
Cummings,
& the CAN
Consensus Group, 1998), espe-
cially
its
recognition
of the
effectiveness
of
appropriate
early intervention programs,
the
urgency
of
early iden-
tification
and
diagnosis
of
autistic spectrum
disorders
that
follows,
and the
necessity
for a
careful neurologic
and
medical examination
in all
children with autism. Specific
recommendations regarding imaging, electrophysiology,
metabolic
and
genetic testing
in
this document
are
sim-
ilar
to
those
from
the CCS
(Geschwind
et
al., 1998).
The
purpose
of the CCS was to
provide guidelines
for
first
tier
autism screening
and
diagnostic referral
for
primary
care
practitioners (primarily pediatricians).
The
major
difference
between
the
current recommendations
and the
CCS is
that
the CCS
recommended only
the
CHAT
(Baron-Cohen
et
al., 1992)
as a
rapid
and
effective
screening tool
to
screen
all
18-month-old children
for
autism,
whereas
in
this current consensus,
the
CHAT
is

Screening
and
Diagnosis
of
Autistic
Spectrum
Disorders
473
grouped along with other screening instruments,
and is
felt
not to be
entirely
sufficient
for
primary care screen-
ing
purposes. Given
the
importance
of
early identifica-
tion,
and the
currently
unacceptable
delays
that occur
between initial parental suspicion
and
diagnosis,
the im-
portance
of
widespread developmental screening begin-
ning
at 18
months cannot
be
overemphasized.
The
American Academy
of
Child
and
Adolescent
Psychiatry (AACAP) Practice Parameters (Volkmar
et
al.,
in
press) were consulted
in the
development
of
this document.
The
documents
are
similar with
two
main
differences
due to the
difference
in
scope
of the two
doc-
uments.
The
AACAP practice parameters
are
concerned
with
aspects
of
diagnosis
and
treatment
of
particular rel-
evance
to
psychiatrists
in
their care
for
children, ado-
lescents,
and
adults with autism
and
related conditions.
The
present document
is
concerned primarily
with
as-
pects
of
assessment, including diagnostic screening,
and
does
not
address aspects
of
treatment.
The
AACAP looks
forward
to
continued participation
in the
effort
to
pro-
vide consensus practice parameters
for
autism.
The
American Academy
of
Pediatrics (AAP) Com-
mittee
on
Children with Disabilities
was
consulted
re-
garding
its own
development
of a
Policy
Statement
regarding
the
role
of the
primary care pediatrician
in the
diagnosis
and
management
of
children with autism,
which
is in
progress (American Academy
of
Pediatrics
Committee
on
Children with Disabilities, 1994).
The
documents
are
also similar with main differences
due to
differences
in
scope
of the
target audience.
The AAP
document
is
concerned chiefly with
the
role
of the
pri-
mary
care pediatrician
and
addresses management strate-
gies
as
well
as
early diagnosis.
RECOMMENDATION
FOR
PARAMETER
REVIEW
The
Panel recommends review
of
these parame-
ters
in 2 to 3
years.
would
promote more positive long range outcomes
for
individuals
with autism.
2.
Continue
to
study
the
usefulness
of
electro-
physiological
techniques
to
clarify
the
role
of
epi-
lepsy
in
autism, especially
in
children with
a
history
of
regression.
3.
Continue
efforts
to
identify
contributing genes
to
determine whether
the
behavioral syndromes which
constitute
the
basis
of
DSM-IV
and
ICD-10 have actual
biologic validity.
4.
Continue efforts
to
identify
the
harbingers,
causes,
and
outcome
of
autistic regression.
5.
Attempt
to
identify
environmental factors, such
as
nonspecific infections
or
other immunologically
me-
diated events, that might contribute
to
triggering
the ex-
pression
of
autistic symptoms
or
regression.
6.
Further research must focus
on the
development
and
validation
of
appropriate tools
to
accurately assess
the
cognitive
and
neuropsychological profile
of
indi-
viduals
with
autism,
as it is
clear that
any of the
cur-
rent
available tools has, despite
the
benefits listed
in
Table
VI,
significant limitations
for use
with autistic
individuals.
7. A
well-designed study
of the
prevalence
of
EEG
abnormalities
and
seizures,
of MRI
abnormalities,
and
of
genetic
and
metabolic abnormalities directly
as-
sociated with autism.
8.
Studies
of the
audiological characteristics
of
autistic individuals
and
development
of
appropriate clin-
ical electrophysiological
and
behavioral procedures
to as-
sess peripheral hearing sensitivity
and
suprathreshold
re-
sponses.
9.
Further basic research
on the
development
of
complex auditory processing
in
children,
to
provide
in-
sight
into
the
emergence
of
early auditory behaviors
considered atypical.
10.
Field trials
on the
results
of
implementing these
guidelines
to
determine
who is
identified diagnostically
by
screening
and the
efficacy
of the
various screening
instruments
in
detecting autism
at
different
ages.
RECOMMENDATIONS
FOR
FUTURE
RESEARCH
1.
Develop
and
validate appropriate screening
tools
with adequate sensitivity
and
specificity
for
autism
in
children prior
to age 1
year, which could
be
feasibly
used
by a
wide range
of
practitioners. Current
evidence suggests that
it is
likely that many children
with
autism
can be
identified
by 12 to 18
months
of
age.
It is the
consensus
of
this Panel that early recog-
nition
can
lead
to
early
access
to
intervention, which
APPENDIX
Contact
Information
for
Recommended
Instruments
Ages
and
Stages Ques-
tionnaire
(ASQ),
Second Edition
Australian Scale
for
Asperger's
Syndrome
Paul
H.
Brookes Publishing
Company
PO Box
10624, Baltimore, Maryland
21285
Telephone:
800-638-3775;
Fax: 410-
337-8539
Garnett,
M. S., &
Attwood,
A. J.
(1998).
The
Australian Scale
for
Asperger's Syndrome (pp.
17-19).
In
Attwood,
T.
(Ed.),

474
Filipek
et al.
Autism
Diagnostic
Interview-Revised
Autism
Diagnostic Obser-
vation Schedule-
Generic
BR1GANCE®
Screens
Checklist
for
Autism
in
Toddlers
(CHAT)
Asperger's Syndrome.
A
Guide
for
Parents
and
Professionals.
London; Jessica Kingsley Pub-
lisher, ISBN 1853025771.
Catherine
Lord
Department
of
Psychiatry, MC3077,
University
of
Chicago
5841
S.
Maryland Ave, Chicago,
IL
60637
Telephone: 773-702-9707; Fax: 773-
834-2742
Curriculum
Associates, Inc.
P.O.
Box
2001, North Billerica,
MA
01862-0901
Telephone:
800-225-0248;
Fax: 800-
366-1158
E-mail:
cainfo@curricassoc.com
Baron-Cohen,
S. et al.
(1992).
Can
autism
be
detected
at 18
months?
The
needle,
the
haystack,
and the
CHAT. British
Journal
of
Psychiatry, 161,
839-843.
Baron-Cohen,
S. et al.
(1996). Psy-
chological markers
in the
detec-
tion
of
autism
in
infancy
in a
large population. British Journal
of
Psychiatry, 168,
158-163.
Behavior Science Systems
Box
580274, Minneapolis,
MN
55458
Telephone:
612-929-6220
Western Psychological Services
12031
Wilshire Boulevard
Los
Angeles,
CA
90025-1251
Telephone:
800-648-8857;
Fax: 310-
478-7838
Ellsworth
and
Vandermeer Press, Ltd.
4405
Scenic
Drive, Nashville,
TN
37204
Telephone: 615-386-0061; Fax: 615-
386-0346
Wendy
Stone
Vanderbilt
Child Development
Center
Medical Center South, Room
426
2100 Pierce Avenue, Nashville,
TN
37232-3573
Telephone:
615-936-0249
E-mail:
wendy.stone@mcmail.van-
derbilt.edu
Bryna
Siegel
Langley
Porter
Psychiatric Institute,
Box
CAS
University
of
California,
San
Fran-
cisco,
CA
94143-0984
Telephone:
415-476-7385;
Fax: 415-
476-7160.
ACKNOWLEDGMENTS
The
authors express their gratitude
to the
follow-
ing
people
who
contributed
to
this endeavor
by
their
Child
Development
Inventories
(CDIs)
Childhood
Autism
Rating
Scale (CARS)
Parents' Evaluation
of
Developmental
Status
(PEDS)
The
Parent Interview
for
Autism
(PIA)
The
Screening Tool
for
Autism
in
Two-Year-
Olds
(STAT)
Pervasive Developmental
Disorders Screening
Test
(PDDST)
participation
in the NIH
State
of the
Science
in
Autism:
Screening
and
Diagnosis Working Conference, June
15-17,
1998: George Anderson, Anthony Bailey,
W.
Ted
Brown, Susan
E.
Bryson, Rebecca Landa,
Jeffrey
Lewine, Catherine Lord, William Mcllvane, Sally
Ozonoff,
Joseph
Piven,
Ricki
Robinson,
Bryna
Siegel,
Vijendra
K.
Singh, Frank Symons,
and Max
Wiznitzer.
The
current authors, participants
and NIH
Liaisons also
participated
in
this working conference.
The
Panel acknowledges with gratitude
the
assis-
tance
of
Stephen Ashwal
as the
AAN-QSS Facilitator
for
this
project,
the
helpful
consultations
of
Frances
P.
Glas-
coe,
and
Donald
J.
Siegel,
and the
assistance
of
Cheryl
Jess,
Kerry
E.
Shea,
and
Jody
Sallah
in
this
endeavor.
This project
was
supported
in
part
by
HD28202/
HD27802/HD35458 (Filipek), HD35482 (Cook
and
Volkmar), HD34565 (Dawson),
HD36080
(Gravel),
HD3546a (Minshew), HD35468 (Rogers)
and
HD03008
(Volkmar)
from
the
National Institute
of
Child Health
and
Human Development;
DC00223
(Gravel)
from
the
National
Institute
of
Deafness
and
Communication Dis-
orders;
MH01389/MH52223
(Cook),
MH47117
(Daw-
son),
and
MH50620
(Stone) from
the
National Institute
of
Mental Health; NS35896 (Filipek), NS33355 (Min-
shew),
NS20489 (Rapin),
from
the
National Institute
of
Neurologic Disorders
and
Stroke, National Institutes
of
Health, Bethesda,
MD.
This project
was
also supported
by
MCJ-369029 (Accardo)
from
the
Maternal
and
Child
Health Bureau, Health Resources
and
Services Admin-
istration,
Department
of
Health
and
Human
Resources.
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