ArticlePDF AvailableLiterature Review

Visual Event-Related Potentials in Mild Cognitive Impairment and Alzheimer's Disease: A Literature Review

Authors:

Abstract and Figures

Background: Cognitive deficits are correlated with increasing age and become more pronounced for people with mild cognitive impairment (MCI) and dementia caused by Alzheimer's disease (AD). Conventional methods to diagnose cognitive decline (i.e., neuropsychological testing and clinical judgment) can lead to false positives. Tools such as electroencephalography (EEG) offer more refined, objective measures of indexing electrophysiological changes associated with healthy aging, MCI, and AD. Objective: We sought to review the EEG literature to determine whether visual event-related potentials (ERPs) can distinguish between healthy aging, MCI, and AD. Method: We searched Medline and PyscInfo for articles published between January 2005 and April 2018. Articles were considered for review if they included participants aged 60+ who were healthy older adults or people with MCI and AD, and examined at least one visually elicited ERP component. Results: Our search revealed 880 records, of which 34 satisfied the inclusion criteria. All studies compared cognitive function between at least two of the three groups (healthy older adults, MCI, and AD). The most consistent findings related to the P100 and the P3b; while the P100 showed no differences between groups, the P3b showed declines in amplitude in MCI and AD. Conclusion: Visually elicited ERPs can offer insight into the cognitive processes that decline in MCI and AD. The P3b may be useful in identifying older adults who may develop MCI and AD, and more research should examine the sensitivity and specificity of this component when diagnosing MCI and AD.
Content may be subject to copyright.
Current Alzheimer Research
ISSN: 1567-2050
eISSN: 1875-5828
Impact
Factor
Current: 3.289
5-Year: 3.595
BENTHAM
SCIENCE
Send Ord ers for R eprints to reprints@benthamscience.ae
Current Alzheimer Research, 2019, 16, 67-89
67
REVIEW ARTICLE
Visual Event-Related Potentials in Mild Cognitive Impairment and
Alzheimer’s Disease: A Literature Review
Cassandra Morrison1,*, Sheida Rabipour1, Vanessa Taler1, Christine Sheppard2 and Frank Knoefel3
1School of Psychology, University of Ottawa, Canada, & Bruyère Research Institute, Ottawa, Canada; 2Bruyère Re-
search Institute, Ottawa, Canada & School of Public Health and Health Systems, University of Waterloo, Waterloo,
Canada; 3Faculty of Medicine, University of Ottawa, Canada, Bruyère Research Institute, & Carleton University, Ot-
tawa, Canada
A R T I C L E H I S T O R Y
Received: May 22, 2 018
Revised: August 26, 2018
Accepted: October 15, 2018
DOI:
10.2174/156720501566618102210103
6
Abstract: Background: Cognitive deficits are correlated with increasing age and become more pro-
nounced for people with mild cognitive impairment (MCI) and dementia caused by Alzheimer’s disease
(AD). Conventional methods to diagnose cognitive decline (i.e., neuropsychological testing and clinical
judgment) can lead to false positives. Tools such as electroencephalography (EEG) offer more refined,
objective measures that index electrophysiological changes associated with healthy aging, MCI, and AD.
Objective: We sought to review the EEG literature to determine whether visual event-related potentials
(ERPs) can distinguish between healthy aging, MCI, and AD.
Method: We searched Medline and PyscInfo for articles published between January 2005 and April
2018. Articles were considered for review if they included participants aged 60+ who were healthy older
adults or people with MCI and AD, and examined at least one visually elicited ERP component.
Results: Our search revealed 880 records, of which 34 satisfied the inclusion criteria. All studies com-
pared cognitive function between at least two of the three groups (healthy older adults, MCI, and AD).
The most consistent findings related to the P100 and the P3b; while the P100 showed no differences be-
tween groups, the P3b showed declines in amplitude in MCI and AD.
Conclusion: Visually elicited ERPs can offer insight into the cognitive processes that decline in MCI and
AD. The P3b may be useful in identifying older adults who may develop MCI and AD, and more re-
search should examine the sensitivity and specificity of this component when diagnosing MCI and AD.
Keywords: Visual event-related potentials, Alzheimer’s disease, Mild cognitive impairment, Electroencephalography, P300,
N200
1. INTRODUCTION
Aging is associated with changes in both cognitive func-
tioning and brain activity patterns (event-related potentials;
ERPs). These ERP changes may be more prominent in those
who experience cognitive decline due to mild cognitive im-
pairment (MCI) and Alzheimer’s disease (AD). MCI is a
condition that causes cognitive decline and is gaining interest
among researchers because of its role as a transitional stage
between healthy aging and dementia caused by AD [1-3].
People with MCI who go on to develop AD experience pro-
gressive deterioration in a variety of cognitive domains
including attention, language, reasoning, and behavior [4, 5].
Although around 12% of people who have MCI progress
to AD annually, others remain stable or develop other types
of dementia [2]. These differing trajectories may be reflected
in differing MCI profiles, based on whether the primary
*Address correspondence to this author at the University of Ottawa, School
of Psychology, Vanier Hall, 136 Jean Jacques Lussier, Ottawa, ON K1N
6N5, Canada; Tel: 613-562-6262 ext:1096; E-mail: cmorr083@uottawa.ca
deficit is in memory (amnestic MCI, aMCI) or in another
cognitive domain such as language (non-amnestic MCI,
naMCI) [6, 7]. MCI may further be classified as stable
(sMCI), where the person does not progress, to AD (i.e.,
their cognitive functions remain stable after the initial de-
cline), progressive (pMCI), where the person goes on to de-
velop AD or another dementia [8]; multiple domain amnestic
MCI (mdaMCI), where there are impairments in other cogni-
tive domains in addition to memory; and single domain am-
nestic MCI (sdaMCI) [9], a decline in one other cognitive
domain in addition to memory [9].
Diagnosis of both MCI and AD is rising due to increased
life expectancy; however, as mentioned in the previous
installment of this review [10], the current methods of diag-
nosis for MCI and AD have many limitations. For example,
tests may accurately diagnose one subtype of MCI but not
others [7]. Additionally, using only neuropsychological tests
can generate many false positives, and multiple testing
methods are therefore needed [11]. One possible avenue to
more accurate diagnosis is the use of electroencephalography
1875-5828/19 $58.00+.00 © 2019 Bentham Science Publishers
Bentham Science Publishers
Personal Use Only
68 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
(EEG). By examining variances in brain activity patterns
(ERPs) during performance of cognitively-demanding visual
tasks, it may be possible to differentiate between these
groups with higher sensitivity and specificity than existing
methods.
Event-related potentials allow researchers to measure
brain responses to specific cognitive functions [12], and to
detect subtle changes in cognitive function between groups.
Each ERP component has a specific amplitude associated
with the intensity of the cognitive process, and a latency that
is associated with the processing time required for the task
[12]. ERPs can be elicited during both passive and active
tasks. Passive tasks do not require the participant to attend to
the stimuli being presented, while active tasks require the
participant to actively engage in the task (e.g., pressing a
button in response to a stimulus) [13, 14]. The components
elicited by passive and active tasks differ, as discussed be-
low. The present review focuses on ERPs elicited during
visual tasks. For a review of ERPs elicited during auditory
tasks, see our previous paper [10].
1.1. ERPs Measured in Visual Tasks
ERP components involved with perceptual and sensory
processing include the N70, N100, P100, N150, N160, and
P200. While the N70 and N150 ERP components are elicited
during visual paradigms involving pattern reversal [15, 16],
the N150 is also involved with early perceptual processing
[17]. Similarly, the P100 is believed to underlie early visual
processing [18] because it is evoked by a variety of visual
stimuli, including colors [19], flashes of light [20], shapes
[21], movement [22], and even the appearance of images
[15]. Both the N100 and P200 components are involved with
primary perceptual processing of incoming information and
early attentional allocation to visual stimuli [23-26]. The
N160 has been identified as ideal for studying the allocation
of attention to visual stimuli [27]. Despite the importance of
these components in studying age-related cognitive decline,
these early visual ERP components are often overlooked in
studies examining ERPs in aging and cognitive decline [e.g.,
28-31]
Middle to long-latency ERP components are among the
most widely-studied and well-understood components. These
include the N2b, N2pc, mismatch negativity (MMN), and
P3b - important components for higher order cognitive proc-
essing in response to a visual stimulus. The N2b reflects
processing of visual stimuli during active attention [32], in-
cluding the processing of motion [33, 34], whereas the N2pc
is specifically related to the processing of a target stimulus
and the ability to shift attention to a target [35, 36]. Another
N2 subcomponent is the negativity central contralateral
(N2cc), which is a measure of cognitive control [36]. The
MMN is associated with the ability to detect stimulus change
without direct attention [37, 38], and is measured with a pas-
sive task. Lastly, the P3b is involved in essential cognitive
processes such as attention and memory [13, 39], and is one
of the most common components analyzed in relation to vis-
ual tasks.
Cognitive functions related to facial recognition, lan-
guage, and memory processing are also associated with ERP
components. The viewing of faces elicits greater amplitudes
in the N170 and N250(r) compared to the viewing of scenes
or non-face objects [40-43]. The N400 reflects processing
involved with lexical/semantic integration, with larger am-
plitudes in response to semantic irregularities [12]. Memory
processing is reflected in several different ERP components,
including the positive negative working memory (WM)
component (PNwm), N300, P450, P600, and contralateral
delay activity (CDA). The PNwm, P450, and CDA are also
associated with WM processing. The PNwm is a relatively
newly-defined component that indexes WM capacity [44].
Similarly, the CDA is a newly-defined component [45]
thought to reflect the encoding and maintenance of items in
visual WM [46]; this component is a good index of an indi-
vidual’s WM capacity [47, 48]. The P450 is involved with
sustained attention and the ability to accommodate new and
relevant information into WM [49]. Finally, the P600 (also
called the late positive component; LPC) is a key component
in the processing of memory encoding [50].
1.2. Age-Related Changes in ER Ps Found in Visual Tasks
This literature review aims to discuss changes in visu-
ally-elicited ERP components in cognitive decline due to
MCI and AD. Prior to addressing the literature on these
populations, we briefly review some of the changes seen in
these components with normal aging.
Studies that have been conducted on age-related changes
in the P100 reported mixed findings: some have reported a
decrease in amplitude [51, 52], while others have found no
age-related changes in amplitude [53, 54]. P100 latency has
also shown mixed results, with one study reporting no
changes due to age [54], and one indicating a P100 prolonga-
tion due to age [53].
Similarly, research on age-related changes in the P200
has been inconsistent. Two studies have reported decreased
amplitude [51, 53], while another found no amplitude change
with age [54]. With respect to P200 latency, two studies re-
ported similar latency between young and older adults [51,
53], and one reported a prolongation with age [54]. The ma-
jority of studies have reported no change in N100 amplitude
with older age [51, 54-56], although some findings are
mixed, with reports of a decrease [22], and an increase [53]
in amplitude. Due to the lack of and inconsistent findings,
more research is needed to understand the influence of age
on the P100 and P200.
The MMN, N2b, and P3b have generated more interest in
aging research than earlier components. The MMN decreases
in amplitude with age [57], suggesting declines in pre-
attentive processing to visual stimuli, and the N2b is delayed
[33, 58, 59], that older adults require more time to process
and attend to a stimulus. Similarly, numerous studies have
found prolonged P3b latency [56, 58-63] with age, indicating
a potential reduction in processing speed [63, 64]. In addi-
tion, decreased amplitudes are found at parietal regions in
older adults compared to young controls [60, 65, 66]. How-
ever, in frontal regions P3b amplitudes appear to increase in
older adults compared to young controls [51, 56, 61-63]. The
amplitude decline in parietal regions is associated with less
efficient performance [56], whereas the increase in frontal
amplitude suggests the need for older adults to recruit addi-
tional regions to complete a task of the same difficulty [51,
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 69
58]. This frontal switch is consistent with the posterior-
anterior shift in aging (PASA): older adults tend to engage
other networks in the frontal region to compensate for de-
clines in processing in the posterior regions [67]. The consis-
tent findings with respect to the N2b and P3b suggest that
these two components may be good indicators of age-related
cognitive declines.
The N170 and N400 have also been examined in the
healthy aging population. One study reported that N170 la-
tency appears to remain stable, whereas the amplitude be-
comes smaller during facial recognition tasks in older adults
compared to young controls [68]. This finding suggests a
decline in the processing of facial stimuli with age. Studies
examining language processing in older adults have reported
smaller amplitudes and prolonged latencies in older adults
relative to young controls [69, 70], suggesting diminished
processing of semantic information with healthy cognitive
aging.
Lastly, the PNwm, N300, P450, P600, and CDA are com-
ponents elicited during tasks requiring memory processing.
Initial research on the PNwm has shown that healthy older
adults exhibit a prolonged and attenuated PNwm compared to
young controls; this difference also becomes more pro-
nounced as task demands increase [44]. Similarly, the P450
shows both decreases in amplitude and prolongations in la-
tency due to age [28]. Smaller P600 [22] and N300 [28] am-
plitudes are also found with increased age, representing de-
creases in memory encoding and retrieval, respectively.
Lastly, the CDA has also shown to decline with age [71],
especially in those at risk of developing MCI [72]. These
component changes are related to declines with memory,
speed, and accuracy declines that occur with healthy aging
[28, 73].
1.3. Present Review
Current literature on ERPs elicited from visual paradigms
in cognitively healthy older adults indicate that some ERP
components (such as the P3b and N2b) can clearly distin-
guish between younger and older adults. Therefore, these
components may also be useful in distinguishing between
healthy aging, MCI, and AD. As discussed in our first litera-
ture review [10], other reviews have begun to examine the
influence of progressive cognitive decline on ERP compo-
nents [74-76]. However, no review to date has examined
ERP components as a function of the type of paradigm used
to elicit the responses (visual paradigm versus auditory para-
digm) or examined (in depth) the effects of MCI on ERP
components. In the present review, we sought to examine
whether visual paradigms can detect declines in different
aspects of cognition (e.g., facial processing, WM, semantic
abilities, visual motion perception) in MCI and AD. The
goals of this paper were to: i) update the literature on visu-
ally-elicited ERPs in MCI and AD; and ii) examine the util-
ity of ERPs as a diagnostic tool for both AD and MCI. This
review will further the existing research by identifying spe-
cific components that may be useful in clinical settings and
future experimental protocols.
2. METHODS
2.1. Search Protocol
A literature search on PsycINFO and Medline was con-
ducted using the following keywords: “Evoked potentials,
Alzheimer’s disease, Cognitive Impairment, and Electroen-
cephalography”. Titles and abstracts were searched using the
terms: “event related potential, ERP, mild cognitive impair-
ment, MCI, EEG, and Alzheimer”. A hand search of refer-
ences in key articles was also conducted to identify addi-
tional articles of relevance. Table 1 for an example of the
search protocol in PsycInfo.
Table 1. Example of the literature search run in PsycInfo.
Abbreviations. ti, title; ab, abstract.
# Searches # of Results
1) Evoked Potentials/ 18737
2) Erp.ti,ab. 11143
3) Event related potential*.ti,ab. 13648
4) Alzheimer’s Disease/ 42023
5) Cognitive Impairment/ 32079
6) Mci.ti,ab. 5718
7) Mild cognitive impairment.ti,ab 8341
8) Electroencephalography/ 23192
9) Eeg.ti,ab. 32591
10) Alzheimer*.ti,ab. 53228
11) 1 or 2 or 3 or 8 or 9 59489
12) 4 or 5 or 6 or 7 or 10 79502
13) 11 or 12 1538
14) Limit 13 to (English and human and last 13 years) 880
2.2. Article Selection
Articles were considered if they were available in Eng-
lish and published between January 2005 and April 2018.
Articles were included if they included participants 60 years
and older with a diagnosis of MCI or AD and if they re-
ported at least one ERP component elicited by visual para-
digms. Articles were excluded if they reported EEG data
with a paradigm (i.e., did not extract ERPs) or used somato-
sensory stimuli to elicit ERPs. Literature reviews, meta-
analyses, and case studies were also excluded. Finally, stud-
ies that only examined differences between young adults and
older adults but did not include an MCI or AD group were
also excluded. Two independent reviewers screened titles
and abstracts to assess inclusion and extract relevant study
data. The remaining articles underwent full text reading by
two independent reviewers to assess inclusion. Discrepancies
were resolved by discussion, including a third reviewer when
required.
Bentham Science Publishers
Personal Use Only
70 Current Alzheimer Research, 2019, Vol. 16, No. 1 Morrison et al.
3. RESULTS
After removing duplicates, we identified 880 titles and
abstracts from our search and selected 84 for full text review
(Fig. 1). A total of 34 articles met the full inclusion criteria
and were included in the review.
Six studies used a visual motion paradigm, 11 used vari-
ous WM tasks (n-back, Simon task, Go-NoGo, Eriksen
flanker task, and delayed matching to sample), four pre-
sented faces or scene pictures, six used a visual oddball task,
one study used a double flash paradigm requiring the partici-
pant to press a button when they saw a strobe flash, and
seven studies examined language processing using word
recognition and repetition, word memory paradigms, seman-
tic priming, or presentation of lexically ambiguous stimuli. A
summary of the ERP components elicited from the above
tasks can be found in Appendix I.
We included only papers that compared at least two of
the three participant groups (healthy older adults, and people
with MCI or AD). Eleven papers compared ERPs between
healthy older adults and people with MCI, 13 compared
healthy older adults to those with AD, and 10 compared
healthy older adults to both people with MCI and people
with AD. There were no studies examining the differences
between MCI and AD without a healthy older adult group.
The studies are summarized in Table 2.
3.1. ERPs in Sensory Processing
3.1.1. N70, N150, & N160
Only one study examined the N70 [15], N150 [15], and
N160 [77]. This study compared healthy older adults to peo-
ple with MCI using a visual pattern reversal paradigm, and
found no group differences in N70 or N150 amplitude or
latency [15]. Within the MCI population, medication did not
impact the N70 or N150 components [15], suggesting that
cholinesterase inhibitors do not affect these early sensory
processes. A second study examined the N160 using oddball
and n-back tasks in healthy older adults, as well as people
with sMCI, pMCI, and AD, and found no difference in N160
latency between any of the four groups [77].
3.1.2. P100
Most studies reported no changes in P100 amplitude in
people with MCI [15, 54, 77-81] and AD [54, 82-85], com-
pared to healthy older adults. However, one study found an
increase in amplitude in MCI and AD [86], and one study
also reported a decline in AD [81]. The lack of P100 differ-
ences between groups extends to latency effects during vis-
ual tasks; none of the studies reported differences in P100
latency across groups [15, 54, 77, 78, 80, 81, 84, 86]. Al-
though one study reported a decrease in latency between
healthy older adults and people with AD, this difference was
only present at one electrode site (O1) [83]).
3.1.3. N100
Four studies indicated no difference in amplitude [54, 79,
80, 85] or latency [54, 80] between people with MCI [79,
80)] or AD [(54, 85]. Two studies reported smaller N100
amplitudes in people with MCI [81] or AD [81, 87)] com-
pared to healthy older adults. No group differences in N100
latency were found in any study [54, 80, 81, 87].
3.1.4. P200
Four of the seven studies examining the P200 focused on
amplitude differences between groups. Two studies found
that people with amnestic MCI (aMCI) [80] and AD [54]
Fig. (1). Flow diagram of search protocol.
Records identified through
database searching
(n = 1538)
Screenin
g
Included Eligibility Identification
Additional records identified
through manual search
(
n = 77
)
Records after duplicates removed
(n = 880)
Records screened
(n = 880)
Records excluded after
title and abstracts
reviewed
(n = 797)
Full-text articles
assessed for eligibility
(n = 83)
Full-text articles
excluded, with reasons
(n = 49)
n = 2 components
obtained through PCA
n = 11 only compared
YA to HC
n = 4 used specified time
frames not components
n = 30 used auditory
components
n = 2 joint auditory and
visual tas
k
Studies included in
qualitative synthesis
(
n = 34
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 71
Table 2. Summary of reviewed articles.
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
Wolk et al.,
(2005)
[97]
N=24
n=12 HC
8 males
Age range:65-86
M= 75.0
n=12 AD
6 males
Age range:55-80
M= 71.8
AD: NINCDS-
ADRDA
Word recogni-
tion/ familiar-
ity (active)
N400:
325-625 ms
AD < HC N.A. HC > discrimina-
tion abilities than
AD
Olichney et
al., (2006)
[87]
N=22
n=11 HC
7 males
Age range: N.R.
M=77.1
n=11 AD
8 males
Age range: N.R.
M=79.4
AD: extensive
NP testing,
laboratory tests.
MMSE
avg:22.9 ± 3.9
Semantic
congruent and
incongruent
statement
pairs – word
repetition
effects (ac-
tive)
N100:
100-250 ms
N400:
400-550 ms
P600:
550-800 ms
AD<HC
1) AD<HC (poste-
rior &midline)
2) AD>HC
(frontal)
3) AD no repeti-
tion effect
AD decreased
repetition effect &
over left channels
(HC was over
right)
AD=HC
AD=HC
N.A.
ACC: HC >AD
Tales et al.,
(2006)
[57]
N=42
n=11 YA
3 males
Age range:20-43
M=28
n=12 HC
2 males
Age range:51-84
M=73
n=8 probable AD
0 males
Age range:52-84
M=73
AD: DSM-IV
& NINCDS-
ADRDA crite-
ria
Press button
to target,
ignore stan-
dard, and
deviant stim-
uli
(active)
vMMN:
250-400 ms
AD=HC
N.A. N.R.
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
72 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
Fernandez et
al., (2007)
[82]
N=26
n=14 HC
Age range: N.R.
M=70.60
n=6 ADhs
Age range: N.R.
M=73.33
n=6 ADls
Age range: N.R.
M=75.00
AD: NINCDS-
ADRDA crite-
ria
Forced choice
visual motion
discrimination
task, press
button indicat-
ing way of
motion
(active)
Pattern:
P100:
60-110 ms,
P200:
210-300 ms, &
N2b:140-250 ms
Visual motion:
N2b:
140-250 ms
Attention:
P3b:
250-700 ms
ADhs=ADls=
HC
1) ADhs&
ADls <HC
2) ADhs = ADls
ADhs&ADls <HC
N.R.
N.R.
N.R.
N.R.
Irimajiri et
al., (2007)
[15]
N=30
n=15 HC
6 males
Age range: N.R.
M=76.3
n=8 T-MCI
6 males
Age range: N.R.
M=73.4
n=7 NT-MCI
4 males
Age range: N.R.
M=74.3
MCI: neuro-
logical and NP
examinations,
family inter-
views and brain
imaging
Visual pattern
reversal (pas-
sive)
N70:
50-90 ms
P100:
90-120 ms
N150:
100-165 ms
MCI=HC
MCI=HC
MCI=HC
MCI=HC
MCI=HC
MCI=HC
N.A.
Liddell et
al., (2007)
[28]
N=1123
n=1008 HC
51.1% males
Age range:6-80
M= 31.63
n=76 SMC
40.8% males
Age range:52-88
M= 64.92
n=20 MCI
50% males
Age range:54-85
M= 73.6
MCI: CDR of
0.5 and referred
by clinician
AD: DSM-IV
criteria by
neurologist
N-back task
(active)
N300:
200-400 ms
P450:
300-540 ms
1) MCI > HC
2) AD < HC
AD<MCI, SMC,
& HC
1) MCI > HC
2) AD > HC
AD=MCI=SM
C=HC
RT and error
rates did not
differ between
groups
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 73
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
n=19 AD
45% males
Age range:58-95
M= 76.61
Missonnier
et al., (2007)
[77]
N=55
n=16 HC
6 males
Age range: N.R.
M= 71.63
n=13 sMCI
3 males
Age range:57-91
M= 82.00
n=16 pMCI
3 males
Age range:57-91
M= 82.13
n=10 AD
3 males
Age range: N.R.
M= 76.60
MCI: CDR 0.5
and 1.5 SD
below on NP
tests. MMSE
between 25-28
AD: CDR 1
and 2 S.D.
below on NP
tests &
NINCDS-
ADRDA.
MMSE below
25
Oddball or n-
back
(active)
P100
Measured at time
of max. peak
N160
Measured at time
of max. peak
P200
Measured at time
of max. peak
N2b
Measured at time
of max. peak
N.R.
N.R.
N.R.
N.R.
AD=pMCI=
sMCI=HC
AD=pMCI=
sMCI=HC
AD & pMCI
>HC & sMCI
AD & pMCI
>HC & sMCI
RT & ACC:
HC=sMCI=
pMCI=AD
Tales et al.,
(2008) [94]
N=28
n=10 HC
4 males
Age range:65-81
M=71.2
n=8 aMCI
6 males
Age range:65-82
M=74.5
n=10 probable
AD
2 males
Age range:67-81
M=75.2
MCI & AD:
DSM-IV &
NINCDS-
ADRDA
Press button
to target,
ignore stan-
dard and
deviant stim-
uli
(active)
vMMN:
140- 250 ms
vMMN:
250-400 ms
AD=aMCI >HC
(HC did not elicit a
vMMN)
AD=aMCI=
HC
N.A.
N.A.
N.R.
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
74 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
Beuzeron-
Mangina et
al., (2009)
[29]
N=75 (33 males)
n=25 HC
Age range: N.R.
M=70.4
n=25 vEAD
Age range: N.R.
M=69.9
n=25 MVD
Age range: N.R.
M=70.1
HC: 6 steps
e.g., MMSE
=30
MCI: 8 steps
e.g., DSM-IV
& MMSE
AD: 7 steps
e.g., DSM-IV
& NINCDS-
ADRDA
Word memory
paradigm -
press button
for target
word
(active)
P450:
300-650 ms
vEAD>HC vEAD>HC
(anterior)
vEAD<HC
(posterior)
No effect of
memory load on
group
Taler et al.,
(2009)
[98]
N=49
n=19 HC
8 males
Age range: N.R.
M=74.68
n=20 MCI
10 males
Age range: N.R.
M=75.80
n=10 AD
3 males
Age range: N.R.
M=82.4
MCI: Petersen
criteria
AD: APA
diagnostic
criteria for
dementia
Exp. 1: Read
lexically am-
biguous items
(passive)
0-350 ms
N400:
300-650 ms
500-650 ms
600-650 ms
AD=MCI=HC
1) AD >HC
2) trend for MCI
>HC
AD >MCI
trend for AD >HC
N.A.
N.A.
N.A.
N.A.
N.A.
Cheng et al.,
(2010)
[83]
N=37
n=17 HC
9 males
Age range: N.R.
M=69.47
n=20 AD
12 males
Age range: N.R.
M=71.05
AD: DSM-IV,
NINCDS-
ADRDA
Familiar/
novel faces &
scenes
(active)
P100:
80-120 ms
N170:
150-180 ms
N250r:
280-330 ms
AD=HC
AD<HC @ P3 and
P4
AD>HC for famil-
iar scene & novel
faces
1) AD=HC @
Oz & O2
2) AD<HC @
O1
AD=HC
AD=HC
AD RT to scene >
face
HC RT to scene =
face
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 75
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
Kubová et
al., (2010)
[84]
N=30
n=15 HC
# males N.R.
Age range:59-85
Median=78.00
n=15 AD
9 males
Age range:58-87
Median=75.00
HC: MMSE
between 28-30
AD: diagnosed
by a neurologic
department &
MMSE be-
tween 12-23
Pattern and
motion
(active)
P100:
Peak latency and
inter-peak abso-
lute mean ampli-
tude
N2b:
Peak latency and
inter-peak abso-
lute mean ampli-
tude
P3b:
Mean inter-peak
latency & ampli-
tudes measured
AD=HC
AD<HC
AD=HC
AD=HC
AD=HC
AD>HC
RT: AD=HC
ACC: HC made
fewer mistakes to
target stimuli
Kurita et al.,
(2010) [90]
N=84
n=20 HC
11 males
Age range: N.R.
M=71.4
n=21 AD
11 males
Age range: N.R.
M=71.7
n=41 other
25 males
AD: DSM-IV
criteria
Visual
discrimination
with human
faces
(active)
N1:
N2b:
Second peak
following P2
P200:
Largest peak
following N1
P3b:
300-800 ms
N.R.
N.R.
N.R.
N.R.
AD=HC
AD=HC
AD=HC
AD>HC
N.R.
Fernandez et
al., (2012)
[33]
N= 43
n=12 YC
# males N.R.
n=16 HC
# males N.R.
Age range: N.R.
M=76.2
n=15 EAD
# males N.R.
Age range: N.R.
M=78.6
AD: NINCDS-
ADRDA crite-
ria
Visual motion
(VM)
(active)
N2b (motion
coherence)
N2b (Speed para-
digm)
Peak deflection
±50 ms for each
person
AD<HC
AD<HC
AD=HC
AD=HC
RT: AD=HC
ACC: AD<HC
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
76 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
Parra et al.,
(2012) [30]
N= 30
n=10 HC
3 males
Age range: N.R.
M=64.70
n=10 MCI
4 males
Age range: N.R.
M=72.60
n=10 AD
4 males
Age range: N.R.
M=74.10
MCI: Petersen
criteria
AD: NINCDS-
ADRDA
Visual oddball
(active)
P3b
Avg latency:
HC 331.78 ms
MCI 537.48 ms
AD 564.31 ms
AD&MCI<HC @
Fz not Pz
AD&MCI>HC N.R.
Saavedra et
al., (2012a)
[96]
N=43
n=16 YC
Age range: N.R.
M=25
n=15 HC
Age range: N.R.
M=83.5
n=5 aMCI
n=7 mild AD
Age range: N.R.
M=81.8
aMCI: Petersen
criteria
AD: NINCDS-
ADRDA
Face familiar-
ity
(active)
N170: (posterior)
160-240 ms
Vertex Positive
Potential:
160-240 ms
AD< HC& YC
AD >YC
N.R.
N.R.
ACC: HC=
MCI=AD
Saavedra et
al., (2012b)
[86]
N=27
n=15 HC
4 males
Age range:65+
M=83.5
n= 12 CI
4 probable AD,
3 possible AD, &
5 MCI
0 males
Age range: N.R.
M=81.8
MCI: Petersen
criteria
AD: NINCDS-
ADRDA
Face familiar-
ity
(active)
P100:
80-120 ms
N170:
150-200 ms
N250:
330-400 ms
N400:
600-680 ms
CI>HC
CI<HC
CI<HC @T6
CI=HC
N.A.
N.A.
N.A.
N.A.
ACC: CI=HC
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 77
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
Yamasaki et
al., (2012)
[54]
N= 72
n=18 YA
6 males
Age range: N.R.
M=28.2
n=18 HC
6 males
Age range: N.R.
M=71.8
n=18 aMCI
6 males
Age range: N.R.
M=72.4
n=18 AD
6 males
Age range: N.R.
M=75.5
aMCI: Petersen
criteria
AD: NINCDS-
ADRDA
Neuropsyc-
holgical as-
sessment also
done: e.g.,
EEG, MMSE,
MRI
Coherent
motion stimuli
-moving white
dots
(passive)
P100& N100
N170
P200(optic flow)
All components:
peak latencies
measured from
the stimulus
onset, and peak
amplitudes meas-
ured from base-
line to peak
AD=aMCI=
HC
AD=aMCI=
HC
1)AD=aMCI
2)AD<HC
AD=aMCI=
HC
1)AD >aMCI
& HC
2)aMCI =HC
AD>aMCI
>HC
N.A.
Cespón et
al., (2013)
[35]
N=55
n=25 HC
14 males
Age range:51-85
M=65.2
n=17 sdaMCI
10 males
Age range:51-85
M=67.0
n=13 mdaMCI
6 males
Age range:51-85
M=71.0
MCI: MMSE,
CVLT, CAM-
DEX-r, IADL
scale, GDS, &
questionnaire
on SMC
Simon Task
(active)
N2pc:
Latency
200-375 ms
Amplitude
250-350ms
LRP-r
-125 ms &
-25 ms regarding
the response
mdaMCI <HC
mdaMCI &
sdaMCI <HC
HC=mdaMCI=
sdaMCI
HC=mdaMCI=
sdaMCI
RT: MCI=HC
ACC:
mdaMCI<
sdaMCI
Fernandez et
al., (2013)
[59]
N=42
n=15 YC
15.47% males
Age range: N.R.
M=26.00
AD: NINCDS-
ADRDA
Visual motion
(VM)
(active)
N200(flow)
N200(VM)
EAD<HC & YC
EAD<HC & YC
N.R.
EAD=HC<YC
EAD=HC<YC
RT: AD=HC
ACC: AD=HC
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
78 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
n=15 HC
15.33 % males
Age range: N.R.
M=75.07
n=12 EAD
12.58% males
Age range: N.R.
M=78.42
N2b(VM)
P3b(VM)
EAD<HC
EAD>HC
EAD>HC
Grieder et
al., (2013)
[85]
N=38
n=19 HC
Age range: N.R.
M=69.5
n=14 AD
Age range: N.R.
M=66.5
n=5 SD
Age range: N.R.
M=65.8
AD: ICD-10
criteria
Semantic
priming para-
digm
(active)
P100 & N100:
94-302 ms
N400:
382-546 ms
AD=HC
AD<HC
N.R.
N.R.
RT: AD>HC
ACC: HC>AD
Schefter et
al., (2013)
[78]
N=32
n=17 HC
7 males
Age range: N.R.
M=68.00
n=15 aMCI
4 males
Age range: N.R.
M=67.13
MCI: reported
memory com-
plaint, cogni-
tive testing, not
normal nor
demented, and
intact ADL
(Winbald et al.,
2004 criteria)
Recognition
memory of
words and
pictures
(active)
P100:
Latency
90-140 ms
Amplitude
104-134 ms
N170:
Latency
160-240 ms
Amplitude
HC:172-202 ms
MCI:189-219 ms
P200:
Latency
240-380 ms
Amplitude
290-320 ms
aMCI=HC
aMCI<HC (angry)
Occurred in oppo-
site hemisphere in
aMCI
aMCI=HC
aMCI>HC
aMCI=HC
RT: aMCI>HC
ACC: aMCI<HC
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 79
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
Spironelli et
al., (2013)
[31]
N=22
n=11 HC
2 males
Age range:69-83
M= 76.36
n=11 AD
2 males
Age range:70-88
M=78.18
AD: 4 step
method e.g.,
evidence of
cortical atrophy
though MRI
Go/NoGo
with words
(active)
N400:
400-600 ms
For non-words AD
< HC (anterior)
AD=HC (poste-
rior)
N.A. RT: AD<HC
AD omissions >
HC
Wang et al.,
(2013) [91]
N=38
n=16 HC
9 males
Age range: N.R.
M=69.3
n=15 MCI
9 males
Age range: N.R.
M=72.9
n=7 AD
3 males
Age range: N.R.
M=68.59
MCI: Petersen
criteria,
CDR=0
AD: NINCDS-
ADRDA &
CDR =1
Modified
Eriksen
flanker task
(active)
N2b:
200-350 ms
P3b:
300-550 ms
AD&MCI< HC
AD&MCI<HC
1)MCI>HC
2)AD=HC
(trend)
AD&MCI
>HC
RT: AD=MCI=
HC
ACC: AD<MCI<
HC
Asaumi et
al.,(2014)
[95]
N=48
n=12 HC
3 males
Age range: N.R.
M=71.0
n=12 HRMG
3 males
Age range: N.R.
M=74.3
n=12 LRMG
6 males
Age range: N.R.
M=71.6
Intermediate
Group: MMSE,
HDS-R, &
CDR
AD: NINCDS-
ADRDA
Oddball with
faces
(active)
P3b:
300-600 ms
Crying face:
1) AD <
LRMG&HC @ Fz
2) AD<HC @ Cz,
Pz, Oz
3) AD&HRMG <
HC @ Cz
Smiling Face:
1) AD<HC @ Cz,
Oz
2) AD<HRMG @
Oz
Crying face:
AD > HRMG,
LRMG, & HC
@ Fz, Pz, Cz,
& Oz
Smiling face:
AD > HRMG,
LRMG, & HC
RT crying: 1)
AD > LRMG,
HRMG, & HC
RT Smiling:
1) AD > LRMG,
HRMG, & HC
2) HRMG >
LRMG
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
80 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
n= 12 AD
7 males
Age range: N.R.
M=74.1
Cespón et
al., (2015a)
[92]
N=53 (22 males)
n=15 HC
Age range: N.R.
M=66.0
n=11 mdnaMCI
Age range: N.R.
M=66.5
n=16 sdaMCI
Age range: N.R.
M=67.1
n=11 mdaMCI
Age range: N.R.
M=69.6
MCI: MMSE,
CVLT, CAM-
DEX-r, subjec-
tive memory
complaints,
IADLs
Simon Task
(active)
N2b:
Latency 200-375
ms
Amplitude ±20
ms peak
N2pc:
Latency
200-375 ms
Amplitude ±20
ms peak
P3b:
Latency 375-700
ms
Amplitude ±20
ms peak
mdaMCI =
mdnaMCI =
sdaMCI = HC
mdaMCI<HC
mdaMCI =
mdnaMCI =
sdaMCI = HC
mdaMCI >
mdnaMCI,
sdaMCI & HC
mdaMCI =
mdnaMCI =
sdaMCI = HC
mdaMCI =
mdnaMCI =
sdaMCI = HC
RT and errors not
influenced by
group
Cespón et
al., (2015b)
[36]
N=43
n= 18 HC
7 males
Age range:60-83
M=68.3
n=13 sdaMCI
8 males
Age range:60-83
M=69.1
n=12 mdaMCI
5 males
Age range:60-83
M=71.2
MCI: MMSE,
CVLT, CAM-
DEX-r, subjec-
tive memory
complaints,
IADLs
Simon Task
(active)
N2cc
Latency
200-400 ms
Amplitude ±20
ms peak
N2pc
Latency
200-400 ms
Amplitude ±20
ms peak
mdaMCI =
mdnaMCI =
sdaMCI = HC
mdaMCI < HC
mdaMCI > HC
& sdaMCI
mdaMCI =
mdnaMCI =
sdaMCI = HC
Errors higher in
mdaMCI
Deiber et
al., (2015)
[79]
N=142
n=55 sCON
22 males
Age range: N.R.
M=73.7
MCI: MMSE,
HAD, IADL, &
CDR.
dCON: 0.5
S.D. lower at
follow up
Attentional
and 2-back
WM task
(active)
PNwm
P100&
N100
1) MCI<sCON
2) sCON= dCON
MCI=dCON=
sCON
N.A.
N.R.
RT & ACC:
MCI=dCON=
sCON
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 81
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
n=42 dCON
12 males
Age range: N.R.
M=73.7
n=45 MCI
30 males
Age range: N.R.
M=75.3
P3b
MCI< sCON &
dCON
N.R.
Fix et al.,
(2015) [89]
N=13
n=8 HC
4 males
Age range: N.R.
M=65.57
n=5 aMCI
4 males
Age range: N.R.
M=78.00
aMCI: used
Albert et al.,
(2011) criteria
Double flash -
press when
see strobe
(active)
P200:
100-300 ms
N.R.
aMCI>HC in
single flash but
not when ISI
was longer
than refractory
period
N.R.
Stothart et
al., (2015)
[81]
N=71
n=26 HC
14 males
Age range:62-88
M=76.0
n=25 aMCI
16 males
Age range:62-91
M=77.3
n=20 AD
7 males
Age range:60-91
M=79.2
AD/MCI: clini-
cal staff evalua-
tion on 6 dif-
ferent areas
according to
DSM-IV &
NINCDS-
ADRDA guide-
lines
Visual oddball
(active)
P100:
75-100 ms
N100:
160-260 ms
vMMN:
difference wave
following N1
P3b:
230-500 ms
1) AD<aMCI&
HC
2) aMCI=HC
1) AD&aMCI
<HC
2) AD=aMCI
1) aMCI<HC
2) AD=HC
AD=aMCI=
HC
AD=aMCI
=HC
AD=aMCI=
HC
N.A.
AD=aMCI=
HC
R.T & ACC:
AD=MCI
=HC
Li et al.,
(2016) [80]
N=46
n=22 HC
14 males
Age range: N.R.
M=69.17
Delayed
match to
sample
(active)
P200:
150-250 ms &
P3b:
250-450 ms
aMCI <HC
aMCI=HC
RT: MCI>HC
ACC:
MCI<HC
(Table 2) contd….
Bentham Science Publishers
Personal Use Only
82 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
Reference Sample: N Method of
diagnosis
Task Component Amplitude Latency Behaviour
n=24 MCI
13 males
Age range: N.R.
M=69.27
P100:
84-140 ms,
N100:
150-210 ms, &
N2b:
230-300 ms
aMCI=HC
aMCI=HC
Mudar et al.,
(2016) [93]
N=50
n=25 HC
9 males
Age range:57-82
M=65.4
n=25 aMCI
9 males
Age range:54-86
M=68.5
MCI: Petersen
criteria
Go/NoGo
(active)
N2b:
150-300 ms
P3b:
250-650 ms
aMCI=HC
aMCI=HC
aMCI>HC
aMCI=HC
RT: MCI=HC
ACC:
MCI > commis-
sion errors than
HC
Lopez-
Zunini et al.,
(2016) [88]
N=32
n=17 HC
6 males
Age range: N.R.
M=72.75
n=15 aMCI
7 males
Age range: N.R.
M=75.60
MCI: diag-
nosed by phy-
sician
N-back
(active)
P200:
100-220 ms
N2b:
200-380 ms
P3b:
400-500 ms
aMCI=HC
aMCI=HC
aMCI<HC
aMCI>HC
@Cpz &Pz
aMCI>HC @
all midline
sites
N.A.
RT: MCI>HC
ACC: MCI<HC
Bagattini et
al., (2017)
[46]
N= 56
n= 20 HC
Age range:60-85
M=69.40
n= 16 aMCI
Age range:60-85
M=75.00
n= 20 AD
Age range:60-85
M=76.30
AD: MMSE ≥
20 & CDR
score less ≤ 2
HC: MMSE >
24 & CDR = 0
MCI: MMSE
24 & CDR =
0.5
Multiple
Object Proc-
essing (active)
N2pc:
250-250 ms
CDA:
450-800 ms
AD=MCI=HC
1) AD < MCI &
HC
2) MCI> AD &
HC
N.A.
N.A.
ACC: AD< MCI
< HC
YC, young controls; HC, healthy controls; sCON, stable controls; dCON, deteriorated controls; SMC, subjective memory complaints; MCI, mild cognitive
impairment; aMCI; amnestic MCI; sMCI, stable mild cognitive impairment; pMCI, progressive mild cognitive impairment; sdMCI, single domain mild cogni-
tive impairment-single; mdMCI, multiple domain-mild cognitive impairment; sdaMCI, single domain amnestic mild cognitive impairment; sdnaMCI, single
domain non-amnestic mild cognitive impairment; mdaMCI multiple domain amnestic mild cognitive impairment; mdnaMCI, multiple domain non-amnestic
mild cognitive impairment; (V)EAD, (very) early Alzheimer’s disease; AD, Alzheimer’s Disease; ADhs, Alzheimer’s disease high sensitivity; ADls, Alz-
heimer’s disease low sensitivity; SD, semantic dementia; MVD, mild vascular dementia; HRMG, high risk intermediate group; LRMG, low risk intermediate
group; SMC, subjective memory complains; NT-MCI, no treatment MCI; T-MCI, treated MCI; IADL, instrumental activities of daily living; GDS; geriatric
depression scale; CVLT, California verbal learning test; CAMDEX-r; Cambridge Examination for Mental Disorders in Elderly; APA; American Psychological
Association; CDR; Clinical Dementia Rating; NINCDS-ADRDA, National Institute of Neurological and Communicative Disorders and Stroke and
the Alzheimer's Disease and Related Disorders Association; DSM-IV & DSM-V, Diagnostic and Statistics Manual fourth & fifth version; HAD, The Hospital
and Anxiety Depression scale; NP; neuropsychological; MoCA, Montreal Cognitive Assessment; MMSE, Mini-Mental Status Examination; MRI, magnetic
resonance imaging; EEG, electroencephalography; vMMN; visual mismatch negativity; PNwm, Positive negative working memory component; CDA, contra-
lateral delay activity; RT, reaction time; ACC, accuracy; N.A., not applicable; N.R., not reported; S.D., standard deviation.
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 83
exhibited smaller P200 amplitudes compared to healthy
older adults. In contrast, two other studies reported no differ-
ences in P200 amplitude between healthy older adults and
people with aMCI [78, 88] and AD [82]. One study exam-
ined scalp distributions of brain activity and found that those
with MCI showed activity in the left hemisphere, whereas in
healthy older adults right hemisphere activity was observed
[78].
Changes in P200 latency due to cognitive decline were
also inconsistent. Four studies indicated that P200 latency is
prolonged in aMCI [54, 88, 89], pMCI [77], and AD [54, 77]
compared to healthy older adults, while three found no group
differences [78, 80, 90]. One study found that the P200 la-
tency could discriminate between people with progressive
and stable MCI, with a sensitivity of 88% and a specificity of
77% [77].
3.2. N200
Five studies found declines in N2b amplitude in people
with MCI and AD compared to healthy controls [33, 59, 82,
84, 91]. Conversely, four studies reported no differences in
the N2b amplitude based on cognitive status, indicating that
attention (or effort required to complete the task) may not
differ between healthy older adults and those with MCI [80,
88, 92, 93]. The differing findings between these studies may
be due to task differences. For example, the tasks that found
similar group performance focused on attention related to
memory [80, 88, 92, 93], whereas the studies that found
group differences focused primarily on attention during vis-
ual motion [33, 59, 82, 84] and perceptual interference [91]
tasks.
Findings relating to N2b latency in MCI and AD have
also been inconsistent. Six studies found a prolonged N2b
component due to MCI [88, 91-93], pMCI [77], and AD [59,
77], whereas five studies have reported no N2b latency dif-
ferences between healthy older adults and those with MCI
(80) and AD [33, 59, 84, 90]. Similarly, N2b latency has
poor sensitivity and specificity (75% and 69% respectively)
in discriminating between stable and progressive MCI [77].
However, one study found higher sensitivity and specificity
(83% and 81%) in discriminating mdaMCI from healthy
older adults, multiple domain non-amnestic MCI, and
sdaMCI [92].
With respect to the N2pc subcomponent of the N200,
three studies have found that people with multiple domain
amnestic MCI have smaller amplitudes but similar latencies
[35, 36, 92] compared to healthy older adults. The same re-
searchers found that N2pc amplitude could distinguish be-
tween healthy older adults and those with multiple domain
amnestic MCI with a sensitivity of 77-91% and a specificity
of 53-76% [35, 36, 92]. However, one study reported no
group differences in N2pc amplitude between healthy older
adults, MCI, and AD [46]. The N2cc showed similar ampli-
tudes but prolonged latencies in people with mdaMCI com-
pared to healthy older adults [36]. When discriminating be-
tween healthy older adults and those with mdaMCI, the N2cc
latency was found to have high sensitivity (92%) and good
specificity (84%) [36].
3.3. MMN
Although the MMN is often used to measure differences
in an automatic response to a change in stimulus presenta-
tion, few studies looked at this component when examining
changes in cognitive functioning. One study reported that
people with MCI have smaller amplitudes compared to
healthy older adults [81]. In contrast, three studies reported
comparable MMN amplitudes between healthy older adults
and people with MCI [94] and AD [57, 81, 94] and between
people with MCI and AD [81, 94]. However, people with
MCI and AD exhibited larger MMN amplitudes than healthy
older adults after repeated exposed to more deviants [57, 94],
suggesting that the ability to detect change decreases in MCI
and AD, and increased exposure to the stimulus is needed for
MCI and AD participants to detect the deviant [57, 94].
3.4. P3b
Twelve studies compared P3b amplitude in healthy older
adults and people with MCI and/or AD. Eight studies re-
ported smaller P3b amplitudes in people with MCI [30, 79,
80, 88, 91] and AD [30, 59, 82, 91, 95] compared to healthy
older adults, while four studies reported no changes in P3b
amplitude as a result of MCI [81, 92, 93] and AD [81, 84].
Despite these promising findings, P3b amplitude has been
found to discriminate between healthy aging and MCI with a
sensitivity and specificity of only 70%, and between healthy
aging and AD with a sensitivity of 80% and specificity of
70% [30].
Findings have been inconsistent with respect to whether
P3b latency changes are observed in MCI. While two studies
have reported increased latency due to MCI [30, 91], four
found no latency differences between healthy older adults
and people with MCI [80, 81, 92, 93]. Only one study found
that P3b latency accurately discriminated between healthy
older adults and people with MCI (sensitivity of 80% and
specificity of 100%) [30]. In AD, latency changes are re-
ported more consistently, with most studies finding that peo-
ple with AD had prolonged latencies compared to healthy
older adults [30, 59, 84, 90, 91, 95], and only one reporting
similar latencies in healthy older adults and people with AD
[81]. One research group reported that people with AD had
longer latencies than both healthy older adults and an inter-
mediate group1 [95]. In another study, P3b latency was found
to discriminate between healthy older adults and people with
AD with a sensitivity and specificity of 100% [30].
3.4. Object/Facial Recognition
3.4.1. N170
Although the N170 is a commonly-studied ERP compo-
nent in facial recognition paradigms, only four studies have
examined this component in relation to cognitive impair-
ment. People with MCI [78, 86] and AD [83, 86, 96] exhib-
ited smaller N170 amplitudes relative to healthy older adults

1 The term “intermediate group” was used to describe a group that scored
between healthy older adults and those with AD, as determined based on the
Revised Hasegawa Dementia scale (scores of 20-28), Mini-Mental State
Examination scores (scores of 23-28), and Clinical Dementia Rating (scores
of 0-1).
Bentham Science Publishers
Personal Use Only
84 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
during facial recognition, although one reported that this
decline was only in response to angry faces [78]. One study
examined the N170 using a visual motion task and found
similar amplitudes across groups, but longer latencies in AD
relative to MCI and healthy aging [54]. With respect to la-
tency changes, one study reported that N170 latency was
delayed in aMCI during recognition memory tasks [78], but
two others found that people with AD [83] and MCI [54] had
similar latencies compared to healthy older adults.
3.4.2. N250
The N250 component has been examined in only two
studies using a visual paradigm. Both of these studies com-
pared healthy older adults to people with MCI and AD and
found conflicting results in terms of amplitude: one reported
an increase in amplitude with AD [83], and the other found
that people with MCI and AD had decreased amplitudes
compared to healthy older adults [86]. Only one of these
studies examined latency between the groups, finding that
healthy older adults and those with MCI and AD had similar
latencies [83].
3.5. Semantic Processing
Research into the N400 component has consistently
found that people with AD exhibit smaller N400 amplitudes
compared to healthy older adults [31, 85, 87, 97], with some
researchers finding these differences only in frontal [31] or
posterior regions [87]. When discriminating between healthy
older adults and AD, N400 amplitude appeared to have an
excellent specificity (91%), although sensitivity was only
55% [87]. Two additional studies reported a more negative
(larger) N400 in AD and MCI patients [87, 98], than healthy
older adults, even though the difference was only found in
frontal sites for AD [87] and only trended towards signifi-
cance for MCI patients [98]. Only one study measured N400
latency, and found similar latencies in healthy older adults
and people with AD [87]. The N400 has also been elicited
during face-feature matching tasks [99] and was similar in
amplitude and latency in healthy older adults and those with
AD during facial recognition tasks [86].
3.6. Memory-related Components
3.6.1. PNwm
People with sMCI exhibited a PNwm; however, those
with pMCI failed to show this component during a WM task
[100]. Although latency results were not reported, one study
found that people MCI exhibited lower PNwm amplitude
than cognitively stable healthy older adults [79].
3.6.2. N300
Only one study has examined memory retrieval deficits
using the N300. These researchers found that people with
MCI had increases in N300 amplitude, whereas those with
AD had decreased amplitudes compared to healthy older
adults [28]. Both those with MCI and those with AD showed
prolonged N300s compared to healthy controls.
3.6.3. P450
We found only two studies that reported on P450 differ-
ences between healthy older adults and people with cognitive
decline, with contradictory findings. One study, using an n-
back task, found smaller amplitudes and similar latencies in
AD compared to healthy older adults and people with MCI
[28] while the other, which examined WM for words, re-
ported increased amplitudes in AD, with prolonged latencies
in anterior regions but shorter latencies in posterior regions
compared to healthy older adults [29].
3.6.4. P600
The one study examining the P600 used a word repetition
task and found that people with AD exhibited a smaller repe-
tition effect that was a topographically atypical (i.e., greater
left frontal amplitude) compared to healthy older adults [87].
In this sample, P600 amplitude discriminated between
healthy aging and AD with a sensitivity of 91% and a speci-
ficity of 73% [87].
3.6.5. CDA
While there have been many studies examining CDA in
healthy aging, we found only one report that examined the
CDA component in people with MCI and AD [46]. People
with MCI showed an increased CDA amplitude compared to
healthy older adults, whereas those with AD showed reduc-
tions in their amplitudes compared to both MCI and healthy
controls [46]. These authors also found that CDA amplitude
could discriminate between healthy older adults and people
with MCI with a specificity of 85% and a sensitivity of 63%,
and between MCI and AD with 80% specificity and 69%
sensitivity [46].
4. DISCUSSION
This review examined 34 studies that measured visually
elicited ERP components in healthy older adults and people
with MCI or AD. After full text review, we categorized the
studies based on the type of processing that the stimulus re-
quired and the cognitive status of the participants involved.
We focused on identifying the visually-elicited ERP compo-
nents that could discriminate between healthy older adults
and people with MCI or AD. This review included seventeen
different components from a wide range of visual tasks.
Although the P100, N2b and P3b were the most com-
monly-studied components, only the P100 and P3b yielded
consistent findings. While conflicting findings have been
reported with respect to the effect of healthy aging on the
P100 [51-54], no differences were observed between healthy
older adults and people with cognitive impairment in P100
amplitude [15, 54, 78-80, 82-85] and latency [15, 54, 77, 78,
80, 81, 84], across all tasks employed. This suggests that
early perceptual processing, indexed by the P100, might not
be affected by MCI and AD. This lack of difference also
indicates that the participants are able to perceive a stimulus,
and that differences in later components are due to changes
in cognitive processing rather than perception.
In addition to the age-related prolongations in P3b la-
tency [56, 58-63] and decreased amplitudes [60, 65, 66],
people experiencing cognitive decline had more reductions
in their P3b amplitudes, suggesting that the P3b may be sen-
sitive to declines due both to age and to decreased cognitive
functioning. The P3b latency appears to be prolonged in
people with AD compared to healthy older adults [30, 59,
84, 90, 91, 95], with less consistent results in MCI [30, 80,
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 85
81, 91-93]. The prolongation in AD but not MCI is likely
due to the severity of the cognitive decline; the reduction in
processing speed observed in MCI may not be severe enough
to differentiate people with MCI from healthy older adults.
The prolongation of the P3b in people with AD indicates that
the time required to process incoming information may in-
crease with cognitive impairment due to AD. Smaller P3b
amplitudes were also consistently found in people with MCI
and AD compared to healthy older adults [30, 59, 79, 80, 82,
88, 91, 95], reflecting declines in memory and attention in
people with cognitive impairment. Although increases in the
frontal regions have been found with healthy older adults
[60, 65, 66], this increase is no longer present in MCI and
AD, perhaps because sufficient cognitive resources are not
available to compensate for declines in memory.
4.1. Limitations in Current Research
Many of the limitations in the visual ERP literature are
similar to those reported in our recent review of studies using
auditory paradigms [10]. Firstly, many researchers fail to
report or control for medication usage in participants [28, 30,
33, 35, 36, 54, 59, 82, 83, 92, 95, 97, 98]. It is essential to
control for medications that influence cognitive and central
nervous system function when measuring brain activity and
cognitive processes, because it is well-established that medi-
cations such as cholinesterase inhibitors influence brain ac-
tivity patterns [101-104]. These medications could mitigate
differences between healthy older adults and those with MCI
and AD because the medications are intended to restore the
brain functioning of those with cognitive impairment. Al-
though the effectiveness of these medications is quite con-
troversial, with some research showing no differences be-
tween those who are on medications and those who are not
[15, 105], it is nonetheless important to control for medica-
tion use in studies including participants with MCI and AD.
Secondly, the exclusion of behavioural measures in the
studies examined in this review [30, 57, 82, 90, 94], is a
cause for concern when studying clinical populations. While
some studies (such as the passive visual paradigms to meas-
ure the MMN) do not require behavioural measures, tasks
that explicitly measure cognitive functioning (i.e., active
tasks) should always examine behavior to ensure that par-
ticipants are completing the task appropriately [106]. For
example, if someone with cognitive impairment forgets the
purpose of the task and obtains a low score (e.g., 50%) then
the brain activity is not representing the cognitive functions
they require to do the task. Without measuring and analyzing
both behavior and brain activity it is difficult to determine
what the changes in brain activity actually represent [107].
The studies reviewed also varied in the time frame and
methods used for measuring ERP components. Some re-
searchers measure amplitude differences using mean area,
while others use peak detection. Taking the average voltage
of a specific time frame generates mean amplitude whereas
the peak amplitude measures the most positive (or negative)
peak in a given time window [12]. In most cases the mean
amplitude offers a more reliable and appropriate measure
than peak detection, because measuring the peak does not
use the same time point across conditions and participants,
and is more susceptible to noise in the data [12]. The use of
peak vs. mean amplitude, as well as the differences in time
window, may contribute to the divergent findings in the dif-
ferent ERP components examined in this review. For exam-
ple, for the N400, where conflicting results have been re-
ported, four of the studies used mean area measures [31, 86,
97, 98] and two used peak detection [85, 87]. Furthermore,
when measuring the N400, all studies in our review meas-
ured the amplitude using different time windows: 325-625ms
[97], 400-550ms [87], 300-650ms [98], 600-680ms [86],
382-546ms [85], 400-600ms [31].
Moreover, many different paradigms can be used when
conducting research using visual tasks. This large range of
tasks facilitates measurement of the processes associated
with a variety of domains such as WM, attention, and dis-
tractibility. However, the use of different tasks is likely the
main contributor to divergent findings between research
studies. For example, the N2b reflects many cognitive proc-
esses such as task difficulty, effort required to complete the
task, conflict adaptation, and cognitive control [108]. There-
fore, comparing the N2 elicited from a variety of tasks with
many levels of task demands is a challenge. In our review,
studies examining the N2b related to memory [80, 88, 92,
93] have found no amplitude differences between healthy
older adults and those with cognitive impairment, but when
examining attention differences during a motion task, differ-
ences due to cognitive impairment were found [33, 59, 82,
84, 91]. Such findings indicate that researchers cannot sim-
ply assume that changes in components are universal when
different tasks are employed. Even within the same cognitive
process, differences in the tasks used can generate different
findings. In this review, two studies that both measured WM
functioning using different tasks (one using an n-back task
with letters [28], and the other using word stimuli [29]),
found opposing results. Although both these tasks measure
WM, they vary in level of difficulty and the amount of re-
sources needed to complete the task. These conflicting re-
sults suggest that differences (or lack thereof) between
groups and studies may be due to the type of task used, some
of which require more resources than others [109]. Future
research should continue to replicate current findings to de-
termine the influence of MCI and AD on varying tasks and
components.
Despite the numerous papers reviewed, minimal research
exists on a number of components: the PNwm, N70, N150,
N160, N300, P450, P600, and CDA. This paucity of studies
limits our ability to evaluate whether these components can
differentiate between people with differing degrees of cogni-
tive impairment. For example, discriminability of the P600
between healthy older adults and people with AD was only
supported by one study [87] and should therefore be repli-
cated to better understand the effects of cognitive impair-
ment on this component. Additionally, the PNwm and CDA
component were only identified in 2003 [44] and 2004 [45],
respectively. Thus, minimal research has been conducted
examining these two components in young and older adults
as well as those with cognitive impairment.
4.2. Recommendations for Future Directions
Future studies should continue to address the limitations
listed above regarding medications, behavioral measures,
and task differences. Medication usage in older adults and
Bentham Science Publishers
Personal Use Only
86 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
patients is common, and these medications may have an in-
fluence on the central nervous system, cognitive functioning,
and brain activity. Therefore, it is essential that researchers
control for these medications and balance their usage be-
tween groups. By completing an analysis with and without
the participants on medications, researchers can determine
whether these medications are in fact influencing the results
of their studies.
Behavioural measures should also be required for studies
using active tasks in healthy older adults and those with cog-
nitive impairment. Such an approach not only allows for
comparisons to other studies, but also ensures that the par-
ticipants understood the task and were completing it cor-
rectly. Additionally, measuring behavioural responses can
assist with the interpretation of the brain activity. The inter-
pretation of group differences in neural activity will vary
depending on whether or not the groups had similar per-
formance and accuracy. For example, P3b amplitude in-
creases when more attention is required and decreases with
increasing task difficulty, due to the availability of fewer
cognitive resources [110]. Therefore, if P3b amplitude is
larger during a more difficult task, it would suggest that
more resources are available to allocate to task completion
[110]. Without comparing P3b amplitudes to behavioural
measures, it is difficult to interpret the results, because a
larger amplitude could be due to either increased available
resources or the requirement of more attention to complete a
task. Increased resources would presumably lead to higher
performance, whereas more attention may result in decreased
accuracy.
It is also important that future research identify universal
tasks to measure specific aspects of cognitive functioning.
This approach would allow comparison of results across
studies, and would ensure that when components are meas-
ured in different studies they are indeed measuring the same
function.
Finally, future research should continue to report the sen-
sitivity and specificity of each component. Only seven of the
34 papers identified in this review reported the sensitivity
and specificity of the components of interest [30, 35, 36, 46,
77, 87, 92]. In addition to identifying group differences
through between-subjects effects, sensitivity and specificity
values are useful to aid in determining whether specific
components can be used for diagnosis on an individual basis.
By indicating a specific time (latency) or voltage (amplitude)
cut-off(s) that can differentiate between groups, the research
will become more clinically-based and may help determine if
ERPs can be used to identify cognitive decline. This data-
drive approach will ensure that appropriate cutoffs (or ranges
for cutoffs) are generated when attempting to diagnose peo-
ple experiencing cognitive decline.
CONCLUSION
Both P3b latency and amplitude showed promise in terms
of effectiveness in discriminating between healthy older
adults and people with MCI and AD. These results suggest
that the P3b may be useful on an individual basis to deter-
mine who will develop MCI and/or AD. However, future
research should continue to examine the sensitivity and
specificity of the P3b in discriminating between groups of
different cognitive status. Additionally, future research
should collect normative data and generate a standardization
of data collection to ensure comparison across groups and
studies is possible. Electrophysiological measures have the
potential to improve differentiation and diagnostic accuracy
between healthy older adults and people with MCI and AD.
Determining who may progress to MCI or AD could in-
crease the probability of people with cognitive impairment
receiving treatment that could slow the progression of their
disorder, as well as facilitating appropriate social, familial,
and financial interventions.
FUNDING
This work was supported by the Canadian Institutes of
Health Research [Grant numbers CNA 137794, 2015]
CONSENT FOR PUBLICATION
Not applicable.
CONFLICT OF INTEREST
The authors declare no conflict of interest, financial or
otherwise.
ACKNOWLEDGEMENTS
Declared none.
APPENDIX I
Pnwm: 2-back and attention task [79].
P100: Semantic priming [85], oddball [81] and n-back task
[77], motion [54, 82, 84] and pattern [15, 82, 84], 2-back and
attention [79], delayed match-to-sample [80], face & scene
recognition [83], face familiarity [86], and recognition mem-
ory tasks [78].
N70 & N150: Pattern tasks [15].
N100: Semantic congruency [87], semantic priming [85],
oddball [81], motion [54], 2-back and attention [79], and
match-to-sample tasks [80].
N160: oddball and n-back task [77].
N170: Motion [54], face and scene recognition [83], face
familiarity [86,96], and recognition memory tasks [78].
P200: oddball [77], pattern [82], motion [54], n-back
[77,88], delayed match-to-sample [80], discrimination of
faces [90], recognition memory [78], and flash tasks [89].
N2b: oddball [77], motion [33,59] and pattern [82,84], n-
back [77,88], delayed match-to-sample [80], discrimination
of faces [90], Simon task [92], go/no-go [93], and Flanker
tasks [91].
N2pc & N2cc: Simon task [35,36,92], and multiple object
processing tasks [46].
N250r: discrimination of faces and scenes [83], face famili-
arity [86].
VPP: Face familiarity [96] .
vMMN: oddball [57,81,94].
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 87
LRP-r: Simon task [35].
P3b: oddball (with [95] and without faces [30,81]), attention
[82], pattern [84], motion [59,84], n-back [88], 2-back and
attention [79], delayed match-to-sample [80], discrimination
of faces [90], Simon task [92], go/no-go [93], and Flanker
task [91].
N300: n-back task [28].
N400: word recognition [97], semantic congruency [87],
semantic priming [85], reading of lexically ambiguous words
[98], face familiarity [86], and go/no-go task [31].
P450: n-back [28] and word memory paradigm [29].
P600: semantic congruency and word repetition effect [87].
CDA: multiple object processing [46].
REFERENCES
[1] Taler V, Phillips NA. Language performance in Alzheimer's dis-
ease and mild cognitive impairment: a comparative review. J Clin
Exp Neuropsychol 30(5): 501-56 (2008).
[2] Petersen RC, Smith GE, Waring SC, Ivnik RJ, Tangalos EG, Kok-
men E. Mild cognitive impairment: clinical characterization and
outcome. Arch Neurol 56(3): 303-8 (1999).
[3] Papaliagkas VT, Kimiskidis VK, Tsolaki MN, Anogianakis G.
Cognitive event-related potentials: longitudinal changes in mild
cognitive impairment. Clin Neurophysiol 122(7): 1322-6 (2011).
[4] Alzheimer’s Disease & Dementia [Internet]. 2016 [cited 2016 Jun
5]. Available from: http://www.alz.org/alzheimers_disease_ what_
is_alzheimers.asp
[5] Golob EJ, Miranda GG, Johnson JK, Starr A. Sensory cortical
interactions in aging, mild cognitive impairment, and Alzheimer’s
disease. Neurobiol Aging 22(5): 755-63 (2001).
[6] Gauthier S, Reisberg B, Zaudig M, Petersen RC, Ritchie K, Broich
K, et al. Mild cognitive impairment. The Lancet 367(9518): 1262-
70 (2006).
[7] Werner P, Korczyn AD. Mild cognitive impairment: conceptual,
assessment, ethical, and social issues. Clin Interven Aging 3(3):
413 (2008).
[8] Bennys K, Rondouin G, Benattar E, Gabelle A, Touchon J. Can
event-related potential predict the progression of mild cognitive
impairment? J Clin Neurophysiol 28(6): 625-32 (2011).
[9] Petersen RC. Mild cognitive impairment as a diagnostic entity. J
Intern Med 256(3): 183-94 (2004).
[10] Morrison C, Rabipour S, Knoefel F, Sheppard C, Taler V. Auditory
event-related potentials in mild cognitive impairment and Alz-
heimer's disease: a literature review. CurrAlzheimer Res 15(8):
702-15 (2018).
[11] Larner AJ. Screening utility of the Montreal Cognitive Assessment
(MoCA): in place of-or as well as-the MMSE? Intern Psychoger
24(3): 391-96 (2012).
[12] Luck S. An introduction to the event-related potential technique.
Cambridge, MA: The MIT Press. 2014
[13] Mertens R, Polich J. P300 from a single-stimulus paradigm: pas-
sive versus active tasks and stimulus modality. Electroencephal
Clin Neurophysiol/Evoked Pot Sec 104(6): 488-97 (1997).
[14] Johnstone SJ, Barry RJ, Anderson JW, Coyle SF. Age-related
changes in child and adolescent event-related potential component
morphology, amplitude and latency to standard and target stimuli in
an auditory oddball task. Intern J Psychophysiol 24(3): 223-38
(1996).
[15] Irimajiri R, Michalewski HJ, Golob EJ, Starr A. Cholinesterase
inhibitors affect brain potentials in amnestic mild cognitive im-
pairment. Brain Res 1145: 108-16 (2007).
[16] Burns NR, Nettelbeck T, Cooper CJ. Event-related potential corre-
lates of some human cognitive ability constructs. Person Indiv Diff
29(1): 157-68 (2000).
[17] Curtis WJ, Cicchetti D. Affective facial expression processing in
young children who have experienced maltreatment during the first
year of life: an event-related potential study. Develop Psychopathol
23(2): 373-95 (2011).
[18] Heinze HJ, Mangun GR. Electrophysiological signs of sustained
and transient attention to spatial locations. Neuropsychologia 33(7):
889-908 (1995).
[19] Hillyard SA, Münte TF. Selective attention to color and location:
an analysis with event-related brain potentials. Percep Psychophy
36(2): 185-98 (1984).
[20] Cobb WA, Dawson GD. The latency and form in man of the oc-
cipital potentials evoked by bright flashes. J Physiol 152(1): 108-21
(1960).
[21] Spehlmann R. The averaged electrical responses to diffuse and to
patterned light in the human. Electroencephal Clin Neurophysiol
19(6): 560-9 (1965).
[22] Jiang Y, Luo YJ, Parasuraman R. Neural correlates of age-related
reduction in visual motion priming. Aging, Neuropsychol Cogn
16(2): 164-82 (2009).
[23] Omoto S, Kuroiwa Y, Otsuka S, Baba Y, Wang C, Li M, et al. P1
and P2 components of human visual evoked potentials are modu-
lated by depth perception of 3-dimensional images. Clin Neuro-
physiol 121(3): 386-91 (2010).
[24] Heinze HJ, Mangun GR, Burchert W, Hinrichs H, Scholz M,
Münte TF, et al. Combined spatial and temporal imaging of brain
activity during visual selective attention in humans. Nature
372(6506): 543-46 (1994).
[25] Wascher E, Hoffmann S, Sänger J, Grosjean M. Visuo-spatial
processing and the N1 component of the ERP. Psychophysiology
46(6): 1270-7 (2009).
[26] Lijffijt M, Lane SD, Meier SL, Boutros NN, Burroughs S, Stein-
berg JL, et al. P50, N100, and P200 sensory gating: relationships
with behavioral inhibition, attention, and working memory. Psy-
chophysiology 46(5): 1059-68 (2009).
[27] McEvoy LK, Pellouchoud E, Smith ME, Gevins A. Neurophysi-
ological signals of working memory in normal aging. Cogn Brain
Res 11(3): 363-76 (2001).
[28] Liddell BJ, Paul RH, Arns M, Gordon N, Kukla M, Rowe D, et al.
Rates of decline distinguish Alzheimer's disease and mild cognitive
impairment relative to normal aging: integrating cognition and
brain function. J Integr Neurosci 6(01): 141-74 (2007).
[29] Beuzeron-Mangina H, Mangina CA. Excessive compensatory
recruitment as a compulsory neurophysiological mechanism in
Very Early Alzheimer's Disease as compared to Mild Vascular
Dementia and to age-matched normal controls. Intern J Psycho-
physiol 73(2): 164-69 (2009).
[30] Parra M, Ascencio L, Urquina H, Manes F, Ibanez A. P300 and
neuropsychological assessment in mild cognitive impairment and
Alzheimer dementia. Front Neurol 3: 172 (2012).
[31] Spironelli C, Bergamaschi S, Mondini S, Villani D, Angrilli A.
Functional plasticity in Alzheimer's disease: Effect of cognitive
training on language-related ERP components. Neuropsychologia
51(8): 1638-48 (2013).
[32] Patel SH, Azzam PN. Characterization of N200 and P300: selected
studies of the event-related potential. Interm J Med Sci 2(4): 147
(2005).
[33] Fernandez R, Duffy CJ. Early Alzheimer's disease blocks responses
to accelerating self-movement. Neurobiol Aging 33(11): 2551-60
(2012).
[34] Haarmeier T, Thier P. An electrophysiological correlate of visual
motion awareness in man. J Cogn Neurosci 10(4): 464-71 (1998).
[35] Cespón J, Galdo-Álvarez S, Díaz F. Electrophysiological correlates
of amnestic mild cognitive impairment in a Simon task. PLoS One
8(12): e81506 (2013).
[36] Cespón J, Galdo-Álvarez S, Díaz F. Inhibition deficit in the spatial
tendency of the response in multiple-domain amnestic mild cogni-
tive impairment. An event-related potential study. Front Aging
Neurosci 7: 68 (2015).
[37] Näätänen R, Jacobsen T, Winkler I. Memory-based or afferent
processes in mismatch negativity (MMN): a review of the evi-
dence. Psychophysiology 42(1): 25-32 (2005).
[38] Näätänen R, Gaillard AW, Mäntysalo S. Early selective-attention
effect on evoked potential reinterpreted. Acta Psychologica 42(4):
313-29 (1978).
[39] Polich J. Updating P300: an integrative theory of P3a and P3b. Clin
Neurophysiol 118(10): 2128-48 (2007).
[40] Blau VC, Maurer U, Tottenham N, McCandliss BD. The face-
specific N170 component is modulated by emotional facial expres-
sion. Behav Brain Func 3(1): 7 (2007).
Bentham Science Publishers
Personal Use Only
88 Current Alzheimer Research, 2019, Vol. 16 , No. 1 Morrison et al.
[41] Eimer M. The face specific N170 component reflects late stages in
the structural encoding of faces. Neuroreport 11(10): 2319-24
(2000).
[42] Schweinberger SR, Huddy V, Burton AM. N250r: a face-selective
brain response to stimulus repetitions. Neuroreport 15(9): 1501-05
(2004).
[43] Schweinberger SR, Pfütze EM, Sommer W. Repetition priming and
associative priming of face recognition: evidence from event-
related potentials. J Exp Psychol: Learning, Memory, Cognition
21(3): 722 (1995).
[44] Missonnier P, Leonards U, Gold G, Palix J, Ibáñez V, Gianna-
kopoulos P. A new electrophysiological index for working memory
load in humans. Neuroreport 14(11): 1451-55 (2003).
[45] Vogel EK, Machizawa MG. Neural activity predicts individual
differences in visual working memory capacity. Nature 428(6984):
748 (2004).
[46] Bagattini C, Mazza V, Panizza L, Ferrari C, Bonomini C, Brignani
D. Neural dynamics of multiple object processing in mild cognitive
impairment and Alzheimer’s disease: future early diagnostic bio-
markers? J Alzheimer's Dis 59(2): 643-54 (2017).
[47] Drew T, Vogel EK. Neural measures of individual differences in
selecting and tracking multiple moving objects. J Neurosci 28(16):
4183-91 (2008).
[48] Ikkai A, McCollough AW, Vogel EK. Contralateral delay activity
provides a neural measure of the number of representations in vis-
ual working memory. J Neurophysiol 103(4): 1963-68 (2010).
[49] Bruce SE, Werner KB, Preston BF, Baker LM. Improvements in
concentration, working memory and sustained attention following
consumption of a natural citicoline-caffeine beverage. Intern J
Food Sci Nutr 65(8): 1003-7 (2014).
[50] Fernández G, Effern A, Grunwald T, Pezer N, Lehnertz K, Düm-
pelmann M, et al. Real-time tracking of memory formation in the
human rhinal cortex and hippocampus. Science 285(5433): 1582-
85 (1999).
[51] O'Connell RG, Balsters JH, Kilcullen SM, Campbell W, Bokde
AW, Lai R, et al. A simultaneous ERP/fMRI investigation of the
P300 aging effect. Neurobiol Aging 33(10): 2448-61 (2012).
[52] Gazzaley A, Clapp W, Kelley J, McEvoy K, Knight RT, D'Esposito
M. Age-related top-down suppression deficit in the early stages of
cortical visual memory processing. Proc Nat Acad Sci 105(35):
13122-26 (2008).
[53] Finnigan S, O'Connell RG, Cummins TD, Broughton M, Robertson
IH. ERP measures indicate both attention and working memory en-
coding decrements in aging. Psychophysiology 48(5): 601-11
(2011).
[54] Yamasaki T, Goto Y, Ohyagi Y, Monji A, Munetsuna S, Minohara
M, et al. Selective impairment of optic flow perception in amnestic
mild cognitive impairment: evidence from event-related potentials.
J Alzheimer's Dis 28(3): 695-708 (2012).
[55] Fogelson N, Shah M, Bonnet-Brilhault F, Knight RT. Electro-
physiological evidence for aging effects on local contextual proc-
essing. Cortex 46(4): 498-506 (2010).
[56] Saliasi E, Geerligs L, Lorist MM, Maurits NM. The relationship
between P3 amplitude and working memory performance differs in
young and older adults. PLoS One 8(5): e63701 (2013).
[57] Tales A, Butler S. Visual mismatch negativity highlights abnormal
preattentive visual processing in Alzheimer's disease. Neuroreport
17(9): 887-90 (2006).
[58] Gajewski PD, Falkenstein M. Age-related effects on ERP and
oscillatory EEG-dynamics in a 2-back task. J Psychophysiol 28(3):
162 (2014).
[59] Fernandez R, Monacelli A, Duffy CJ. Visual motion event related
potentials distinguish aging and Alzheimer's disease. J Alzheimer's
Dis 36(1): 177-83 (2013).
[60] Lorenzo-López L, Amenedo E, Pascual-Marqui RD, Cadaveira F.
Neural correlates of age-related visual search decline: a combined
ERP and sLORETA study. Neuroimage 41(2): 511-24 (2008).
[61] Fujiyama H, Garry MI, Martin FH, Summers JJ. An ERP study of
age-related differences in the central cost of interlimb coordination.
Psychophysiology 47(3): 501-11 (2010).
[62] Daffner KR, Chong H, Sun X, Tarbi EC, Riis JL, McGinnis SM, et
al. Mechanisms underlying age-and performance-related differ-
ences in working memory. J Cogn Neurosci 23(6): 1298-314
(2011).
[63] Vallesi A. Targets and non-targets in the aging brain: a go/nogo
event-related potential study. Neurosci Lett 487(3): 313-37 (2011).
[64] Salthouse TA. The processing-speed theory of adult age differences
in cognition. Psychol Rev 103(3): 403 (1996).
[65] Wild-Wall N, Falkenstein M, Gajewski PD. Age-related differ-
ences in working memory performance in a 2-back task. Front Psy-
chol 2: 186 (2011).
[66] Hogan MJ, Kenney JP, Roche RA, Keane MA, Moore JL, Kaiser J,
et al. Behavioural and electrophysiological effects of visual paired
associate context manipulations during encoding and recognition in
younger adults, older adults and older cognitively declined adults.
Exp Brain Res 216(4): 621-33 (2012).
[67] Davis SW, Dennis NA, Daselaar SM, Fleck MS, Cabeza R. Que
PASA? The posterior-anterior shift in aging. Cerebral Cortex
18(5): 1201-19 (2007).
[68] de Fockert JW, Ramchurn A, Van Velzen J, Bergström Z, Bunce
D. Behavioral and ERP evidence of greater distractor processing in
old age. Brain Res 1282: 67-73 (2009).
[69] Kutas M, Iragui V. The N400 in a semantic categorization task
across 6 decades. Electroencephalogr Clin Neurophysiol 108(5):
456-71 (1998).
[70] Kemmotsu N, Girard HM, Kucukboyaci NE, McEvoy LK, Hagler
DJ, Dale AM, et al. Age-related changes in the neurophysiology of
language in adults: relationship to regional cortical thinning and
white matter microstructure. J Neurosci 32(35): 12204-13 (2012).
[71] Sander MC, Werkle-Bergner M, Lindenberger U. Contralateral
delay activity reveals life-span age differences in top-down modu-
lation of working memory contents. Cereb Cortex 21(12): 2809-19
(2011).
[72] Newsome RN, Pun C, Smith VM, Ferber S, Barense MD. Neural
correlates of cognitive decline in older adults at-risk for developing
MCI: evidence from the CDA and P300. Cogn Neurosci 4(3-4):
152-62 (2013).
[73] Park DC, Lautenschlager G, Hedden T, Davidson NS, Smith AD,
Smith PK. Models of visuospatial and verbal memory across the
adult life span. Psychol Aging 17(2): 299 (2002).
[74] Pedroso RV, Fraga FJ, Corazza DI, Andreatto CA, Coelho FG,
Costa JL, et al. P300 latency and amplitude in Alzheimer's disease:
a systematic review. Braz J Otorhinolaryngol 78(4): 126-32 (2012).
[75] Olichney JM, Hillert DG. Clinical applications of cognitive event-
related potentials in Alzheimer's disease. Phy Med Rehabil Clin
North America 15(1): 205-33 (2004).
[76] Howe AS. Meta-analysis of the endogenous N200 latency event-
related potential subcomponent in patients with Alzheimer’s dis-
ease and mild cognitive impairment. Clin Neurophysiol 125(6):
1145-51 (2014).
[77] Missonnier P, Deiber MP, Gold G, Herrmann FR, Millet P, Michon
A, et al. Working memory load-related electroencephalographic
parameters can differentiate progressive from stable mild cognitive
impairment. Neuroscience 150(2): 346-56 (2007).
[78] Schefter M, Werheid K, Almkvist O, Lönnqvist-Akenine U, Kath-
mann N, Winblad B. Recognition memory for emotional faces in
amnestic mild cognitive impairment: an event-related potential
study. Aging Neuropsychol Cogn 20(1): 49-79 (2013).
[79] Deiber MP, Meziane HB, Hasler R, Rodriguez C, Toma S, Acker-
mann M, et al. Attention and working memory-related EEG mark-
ers of subtle cognitive deterioration in healthy elderly individuals. J
Alzheimer's Dis 47(2): 335-49 (2015).
[80] Li BY, Tang HD, Chen SD. Retrieval deficiency in brain activity of
working memory in amnesic mild cognitive impairment patients: a
brain event-related potentials study. Front Aging Neurosci 8: 54
(2016).
[81] Stothart G, Kazanina N, Näätänen R, Haworth J, Tales A. Early
visual evoked potentials and mismatch negativity in Alzheimer's
disease and mild cognitive impairment. J Alzheimer's Dis 44(2):
397-408 (2015).
[82] Fernandez R, Kavcic V, Duffy CJ. Neurophysiologic analyses of
low-and high-level visual processing in Alzheimer dis-
ease. Neurology 68(24): 2066-76 (2007).
[83] Cheng PJ, Pai MC. Dissociation between recognition of familiar
scenes and of faces in patients with very mild Alzheimer disease:
an event-related potential study. Clin Neurophysiol 121(9): 1519-
25 (2010).
[84] Kubová Z, Kremláček J, Vališ M, Langrová J, Szanyi J, Vít F, et
al. Visual evoked potentials to pattern, motion and cognitive stim-
uli in Alzheimer’s disease. Documenta Ophthalmologica 121(1):
37-49 (2010).
Bentham Science Publishers
Personal Use Only
Visual Event-Related Potentia ls in MCI and AD Current Alzheimer Research, 2019, Vol. 16, No. 1 89
[85] Grieder M, Crinelli RM, Jann K, Federspiel A, Wirth M, Koenig T,
et al. Correlation between topographic N400 anomalies and re-
duced cerebral blood flow in the anterior temporal lobes of patients
with dementia. J Alzheimer's Dis 36(4): 711-31 (2013).
[86] Saavedra C, Iglesias J, Olivares EI. Event-related potentials elicited
by face identity processing in elderly adults with cognitive impair-
ment. Exp Aging Res 38(2): 220-45 (2012).
[87] Olichney JM, Iragui VJ, Salmon DP, Riggins BR, Morris SK,
Kutas M. Absent event-related potential (ERP) word repetition ef-
fects in mild Alzheimer's disease. Clin Neurophysiol 117(6): 1319-
30 (2006).
[88] Lopez Zunini RA, Knoefel F, Lord C, Dzuali F, Breau M, Sweet L,
et al. Event-related potentials elicited during working memory are
altered in mild cognitive impairment. Intern J Psychophysiol 109:
1-8 (2016).
[89] Fix ST, Arruda JE, Andrasik F, Beach J, Groom K. Using visual
evoked potentials for the early detection of amnestic mild cognitive
impairment: a pilot investigation. Intern J Geriat Psychiat 30(1):
72-9 (2015).
[90] Kurita A, Murakami M, Takagi S, Matsushima M, Suzuki M. Vis-
ual hallucinations and altered visual information processing in
Parkinson disease and dementia with Lewy bodies. Move Disord
25(2): 167-71 (2010).
[91] Wang P, Zhang X, Liu Y, Liu S, Zhou B, Zhang Z, et al. Percep-
tual and response interference in Alzheimer’s disease and mild
cognitive impairment. Clin Neurophysiol 124(12): 2389-96 (2013).
[92] Cespón J, Galdo-Alvarez S, Pereiro AX, Diaz F. Differences be-
tween mild cognitive impairment subtypes as indicated by event-
related potential correlates of cognitive and motor processes in a
Simon task. J Alzheimer's Dis 43(2): 631-47 (2015).
[93] Mudar RA, Chiang HS, Eroh J, Nguyen LT, Maguire MJ, Spence
JS, et al. The effects of amnestic mild cognitive impairment on
Go/NoGo semantic categorization task performance and event-
related potentials. J Alzheimer's Dis 50(2): 577-90 (2016).
[94] Tales A, Haworth J, Wilcock G, Newton P, Butler S. Visual mis-
match negativity highlights abnormal pre-attentive visual process-
ing in mild cognitive impairment and Alzheimer's disease. Neuro-
psychologia 46(5): 1224-32 (2008).
[95] Asaumi Y, Morita K, Nakashima Y, Muraoka A, Uchimura N.
Evaluation of P300 components for emotion loaded visual event re-
lated potential in elderly subjects, including those with dementia.
Psychiat Clin Neurosci 68(7): 558-67 (2014).
[96] Saavedra C, Olivares EI, Iglesias J. Cognitive decline effects at an
early stage: evidence from N170 and VPP. Neurosci Lett 518(2):
149-53 (2012).
[97] Wolk DA, Schacter DL, Berman AR, Holcomb PJ, Daffner KR,
Budson AE. Patients with mild Alzheimer's disease attribute con-
ceptual fluency to prior experience. Neuropsychologia 43(11):
1662-72 (2005).
[98] Taler V, Klepousniotou E, Phillips NA. Comprehension of lexical
ambiguity in healthy aging, mild cognitive impairment, and mild
Alzheimer's disease. Neuropsychologia 47(5): 1332-43 (2009).
[99] Olivares EI, Iglesias J, Rodríguez-Holguín S. Long-latency ERPs
and recognition of facial identity. J Cogn Neurosci 15(1): 136-51
(2003).
[100] Missonnier P, Gold G, Fazio-Costa L, Michel JP, Mulligan R,
Michon A, et al. Early event-related potential changes during
working memory activation predict rapid decline in mild cognitive
impairment. J Gerontol Series A: Biol Sci Med Sci 60(5): 660-66
(2005).
[101] Cancelli I, Cadore IP, Merlino G, Valentinis L, Moratti U, Ber-
gonzi P, et al. Sensory gating deficit assessed by P50/Pb middle la-
tency event related potential in Alzheimer’s disease. J Clin Neuro-
physiol 23(5): 421-5 (2006).
[102] Chang YS, Chen HL, Hsu CY, Tang SH, Liu CK. Parallel im-
provement of cognitive functions and p300 latency following
donepezil treatment in patients with alzheimer's disease: a case-
control study. J Clin Neurophysiol 31(1): 81-5 (2014).
[103] Hammond EJ, Meador KJ, Aung-Din R, Wilder BJ. Cholinergic
modulation of human P3 event related potentials. Neurology 37(2):
346-50 (1987).
[104] Dierks T, Frölich L, Ihl R, Maurer K. Event-related potentials and
psychopharmacology. Pharmacopsychiatry 27(02): 72-4 (1994).
[105] Vaitkevičius A, Kaubrys G, Audronytė E. Distinctive effect of
donepezil treatment on P300 and N200 subcomponents of auditory
event-related evoked potentials in Alzheimer disease patients. Med
Sci Monit 21: 1920 (2015).
[106] Goodin DS. Event-Related Potentials. In: Michael J. Aminoff,
editor. Electrodiagnosis in Clinical Neurology. Fifth Edit. Elsevier
Inc.; 1999. p. 609-26.
[107] Wilkinson D, Halligan P. The relevance of behavioural measures
for functional-imaging studies of cognition. Nat Rev Neurosci 5(1):
67 (2004).
[108] Folstein JR, Van Petten C. Influence of cognitive control and
mismatch on the N2 component of the ERP: a review.
Psychophysiology 45(1): 152-70 (2008).
[109] Ashford JW, Coburn KL, Rose TL, Bayley PJ. P300 energy loss in
aging and Alzheimer's disease. J Alzheimer's Dis 26(s3): 229-38
(2011).
[110] Kok A. On the utility of P3 amplitude as a measure of processing
capacity. Psychophysiology 38(3): 557-77 (2001).
Bentham Science Publishers
Personal Use Only
... Research on MCI is also being conducted using electroencephalography (EEG), which is non-invasive and relatively inexpensive and allows for measurements with minimal spatial constraints. Studies using EEG often focus on measuring event-related potentials (ERPs), taking advantage of the temporal resolution, which is a prominent feature of brain waves [12]. ERPs consist of different components, including positive and negative components, which occur over time after stimulus onset, and each has a different meaning [13,14]. ...
... Specific activity is observed in rs-EEG activity in MCI [55][56][57]. Therefore, we used the same frequency bands of interest (delta [2][3][4], theta [4][5][6][7][8], alpha [8][9][10][11][12][13], beta [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], and gamma ) which were set to the same frequency bands as in previous studies comparing healthy older adults, MCI, and AD using eLORETA-ICA [31]. Neural activity was calculated using global field power values [25]. ...
... This may be the result of capturing controlrelated N2 components. Previous studies have reported differences in the latency and amplitude of the N2 and P3 components in HC and MCI patients and reported no differences [12]. For example, a series of studies on MCI measured ERP during the Simon task; some reported no difference in the latency of the N2 component in MCI, whereas others reported a difference in the latency and amplitude of the N2 component [21,70,80]. ...
Article
Full-text available
Background Neurodegeneration and structural changes in the brain due to amyloid deposition have been observed even in individuals with mild cognitive impairment (MCI). EEG measurement is considered an effective tool because it is noninvasive, has few restrictions on the measurement environment, and is simple and easy to use. In this study, we investigated the neurophysiological characteristics of community-dwelling older adults with MCI using EEG. Methods Demographic characteristics, cognitive function, physical function, resting-state MRI and electroencephalogram (rs-EEG), event-related potentials (ERPs) during Simon tasks, and task proportion of correct responses and reaction times (RTs) were obtained from 402 healthy controls (HC) and 47 MCI participants. We introduced exact low-resolution brain electromagnetic tomography-independent component analysis (eLORETA-ICA) to assess the rs-EEG network in community-dwelling older adults with MCI. Results A lower proportion of correct responses to the Simon task and slower RTs were observed in the MCI group (p < 0.01). Despite no difference in brain volume between the HC and MCI groups, significant decreases in dorsal attention network (DAN) activity (p < 0.05) and N2 amplitude of ERP (p < 0.001) were observed in the MCI group. Moreover, DAN activity demonstrated a correlation with education (Rs = 0.32, p = 0.027), global cognitive function (Rs = 0.32, p = 0.030), and processing speed (Rs = 0.37, p = 0.010) in the MCI group. The discrimination accuracy for MCI with the addition of the eLORETA-ICA network ranged from 0.7817 to 0.7929, and the area under the curve ranged from 0.8492 to 0.8495. Conclusions The eLORETA-ICA approach of rs-EEG using noninvasive and relatively inexpensive EEG demonstrates specific changes in elders with MCI. It may provide a simple and valid assessment method with few restrictions on the measurement environment and may be useful for early detection of MCI in community-dwelling older adults.
... In a recent review of visual event potentials by Morrison and colleagues (2019), twelve studies compared P300 amplitude in healthy older adults, in MCI, and/or in AD dementias. In eight studies, they found that P3b amplitude decreased in MCI and AD compared to healthy controls, while four studies did not find any amplitude difference between groups 23 . Another systematic review showed that sixteen of 29 studies indicated no significant amplitude differences between P300 in MCI and healthy controls, while 11 studies showed smaller amplitudes in MCI 24 . ...
... Some studies showed no difference in the latency of P300 in MCI compared to healthy controls. However, a few studies suggested a delay in P300 and P3b latency in MCI (For reviews, see [23][24][25]. These inconsistencies may have been caused by differences in task designs and the heterogeneity of the MCI groups. ...
Article
Full-text available
Alterations in P300 amplitude and latency, as well as neuropsychological tests, are informative to detect early signs of the affected high cognitive processing in Mild Cognitive Impairment (MCI). In the present study, we examined P300 latency and amplitude elicited by visual oddball paradigm in 20 participants with MCI and age, education, and sex-matched healthy controls from frontal, central, and parietal midline electrodes. We performed a mixed-design ANOVA to compare P300 amplitude and latency between groups during target and non-target stimulus presentation. We also assessed the correlation between our electrophysiology findings and neuropsychological tests. Our results indicated that in healthy individuals P300 is elicited earlier in target stimulus processing compared to non-target stimulus processing. On the contrary, in the MCI group, P300 latency was increased during target processing compared to non-target stimulus processing. Moreover, P300 latency in target processing is prolonged in the MCI group compared to controls. Also, our correlation results showed a significant correlation between P300 peak latency and amplitude, and attention required cognitive tasks. In conclusion, our results provide evidence that high-order cognitive processes that are involved in stimulus processing slows down in individuals with MCI due to the high working memory demand for neural processing.
... Although vERPs have previously been studied in individuals with established MCI or AD (e.g., [50][51][52]), to our knowledge, this is the first study to demonstrate vERP deficits associated with amyloid levels in pre-symptomatic individuals. To the extent that prior studies have been conducted, deficits have been observed primarily in later stages of visual processing, such as the higher-level processing within the dorsal visual stream, whereas earlier stages of processing were intact (rev. in [53,54]). ...
Article
Full-text available
Background Amyloid deposition is a primary predictor of Alzheimer’s disease (AD) and related neurodegenerative disorders. Retinal changes involving the structure and function of the ganglion cell layer are increasingly documented in both established and prodromal AD. Visual event-related potentials (vERP) are sensitive to dysfunction in the magno- and parvocellular visual systems, which originate within the retinal ganglion cell layer. The present study evaluates vERP as a function of amyloid deposition in aging, and in mild cognitive impairment (MCI). Methods vERP to stimulus-onset, motion-onset, and alpha-frequency steady-state (ssVEP) stimuli were obtained from 16 amyloid-positive and 41 amyloid-negative healthy elders and 15 MCI individuals and analyzed using time–frequency approaches. Social cognition was assessed in a subset of individuals using The Awareness of Social Inference Test (TASIT). Results Neurocognitively intact but amyloid-positive participants and MCI individuals showed significant deficits in stimulus-onset (theta) and motion-onset (delta) vERP generation relative to amyloid-negative participants (all p < .01). Across healthy elders, a composite index of these measures correlated highly (r = − .52, p < .001) with amyloid standardized uptake value ratios (SUVR) and TASIT performance. A composite index composed of vERP measures significant differentiated amyloid-positive and amyloid-negative groups with an overall classification accuracy of > 70%. Discussion vERP may assist in the early detection of amyloid deposition among older individuals without observable neurocognitive impairments and in linking previously documented retinal deficits in both prodromal AD and MCI to behavioral impairments in social cognition.
... There are inconsistencies in the literature regarding the existence of changes in the latency and amplitude of the P100 wave (EEG; analog of the M100 studied here) among AD patients. Many studies, especially those not specifically designed to measure visual function (i.e., cognitive functioning), do not find alterations in the P100 latency and amplitude [57]. Other studies, mainly those specifically designed to measure visual evoked potentials (VEPs), report a delay in P100 latency, as well as a decrease in its amplitude in AD patients [58][59][60]. ...
Article
Full-text available
Background The earliest pathological features of Alzheimer’s disease (AD) appear decades before the clinical symptoms. The pathology affects the brain and the eye, leading to retinal structural changes and functional visual alterations. Healthy individuals at high risk of developing AD present alterations in these ophthalmological measures, as well as in resting-state electrophysiological activity. However, it is unknown whether the ophthalmological alterations are related to the visual-related electrophysiological activity. Elucidating this relationship is paramount to understand the mechanisms underlying the early deterioration of the system and an important step in assessing the suitability of these measures as early biomarkers of disease. Methods In total, 144 healthy subjects: 105 with family history of AD and 39 without, underwent ophthalmologic analysis, magnetoencephalography recording, and genotyping. A subdivision was made to compare groups with less demographic and more risk differences: 28 high-risk subjects (relatives/APOEɛ4 +) and 16 low-risk (non-relatives/APOEɛ4 −). Differences in visual acuity, contrast sensitivity, and macular thickness were evaluated. Correlations between each variable and visual-related electrophysiological measures (M100 latency and time–frequency power) were calculated for each group. Results High-risk groups showed increased visual acuity. Visual acuity was also related to a lower M100 latency and a greater power time–frequency cluster in the high-risk group. Low-risk groups did not show this relationship. High-risk groups presented trends towards a greater contrast sensitivity that did not remain significant after correction for multiple comparisons. The highest-risk group showed trends towards the thinning of the inner plexiform and inner nuclear layers that did not remain significant after correction. The correlation between contrast sensitivity and macular thickness, and the electrophysiological measures were not significant after correction. The difference between the high- and low- risk groups correlations was no significant. Conclusions To our knowledge, this paper is the first of its kind, assessing the relationship between ophthalmological and electrophysiological measures in healthy subjects at distinct levels of risk of AD. The results are novel and unexpected, showing an increase in visual acuity among high-risk subjects, who also exhibit a relationship between this measure and visual-related electrophysiological activity. These results have not been previously explored and could constitute a useful object of research as biomarkers for early detection and the evaluation of potential interventions’ effectiveness.
... ERP P300 can be used for the early assessment of cognitive decline in patients with AD. Indeed, numerous studies have shown abnormalities/differences in P300 amplitude and latency in patients with both MCI and AD [47][48][49]. Furthermore, P300 studies have been able to sensitively track progression of MCI and AD dementia over time [50][51][52][53]. Several studies have also shown that ERP P300 can detect differences in P300 latency in people with a family history of AD as compared to age-matched controls [39,[54][55][56]. ...
Article
Full-text available
Neurodegenerative diseases, such as Alzheimer’s disease (AD), and their associated deterioration of cognitive function are common causes of disability. The slowly developing pathology of neurodegenerative diseases necessitates early diagnosis and monitored long-term treatment. Lack of effective therapies coupled with an improved rate of early diagnosis in our aging population have created an urgent need for the development of novel drugs, as well as the need for reliable biomarkers for treatment response. These issues are especially relevant for AD, in which the rate of clinical trial drug failures has been very high. Frequently used biomarker evaluation procedures, such as positron emission tomography or cerebrospinal fluid measurements of phospho-tau and amyloid beta, are invasive and costly, and not universally available or accessible. This review considers the functionality of the event-related potential (ERP) P300 methodology as a surrogate biomarker for predicting the procognitive potential of drugs in clinical development for neurocognitive disorders. Through the application of standardized electroencephalography (EEG) described here, ERP P300 can be reliably measured. The P300 waveform objectively measures large-scale neuronal network functioning and working memory processes. Increased ERP P300 latency has been reported throughout the literature in disorders of cognition, supporting the potential utility of ERP P300 as a biomarker in many neurological and neuropsychiatric disorders, including AD. Specifically, evidence presented here supports ERP P300 latency as a quantitative, unbiased measure for detecting changes in cognition in patients with AD dementia through the progression from mild to moderate cognitive impairment and after drug treatment.
Article
Full-text available
More and more patients worldwide are diagnosed with dementia, which emphasizes the urgent need for early detection markers. In this study, we built on the auditory hypersensitivity theory of a previous study-which postulated that responses to auditory input in the subcortex as well as cortex are enhanced in cognitive decline-and examined auditory encoding of natural continuous speech at both neural levels for its indicative potential for cognitive decline. We recruited study participants aged 60 years and older, who were divided into two groups based on the Montreal Cognitive Assessment, one group with low scores (n = 19, participants with signs of cognitive decline) and a control group (n = 25). Participants completed an audiometric assessment and then we recorded their electroencephalography while they listened to an audiobook and click sounds. We derived temporal response functions and evoked potentials from the data and examined response amplitudes for their potential to predict cognitive decline, controlling for hearing ability and age. Contrary to our expectations, no evidence of auditory hypersensitivity was observed in participants with signs of cognitive decline; response amplitudes were comparable in both cognitive groups. Moreover, the combination of response amplitudes showed no predictive value for cognitive decline. These results challenge the proposed hypothesis and emphasize the need for further research to identify reliable auditory markers for the early detection of cognitive decline.
Chapter
Full-text available
The organization of the human afferent visual system is complex and visual processing requires enormous computational challenges and energy consumption at each stage of the visual pathway. Once the eye receives visual information, the signal is relayed by the retina, optic nerve, chiasm, tracts, lateral geniculate nucleus, and optic radiations to the striate and extra-striate association cortical areas for final visual processing. In the retina, photoreceptors convert light photons to electrochemical signals that are relayed to retinal ganglion cells via intermediate neurons. Ganglion cell axons run through the optic nerve, and after their partial decussation at the level of the optic chiasm, they reach the lateral geniculate nucleus where corresponding inputs from each hemiretina overlap. A minority of optic nerve axons target subthalamic nuclei that mediate pupil light reflexes and circadian rhythms. Axons originating from the lateral geniculate nucleus relay visual information through the optic radiations to the striate cortex. Feedback mechanisms from higher cortical areas shape the neuronal responses in early visual areas, supporting coherent visual perception. Detailed knowledge of the anatomy of the afferent visual system, in combination with skilled examination, allows precise localization of neuropathological processes and guides effective diagnosis and management of neuro-ophthalmic disorders. Assessment of all stages of visual system processing is allowed by a set of psychophysical and electrophysiological tests that is crucial in the clinical practice. This chapter encompasses the psychophysical basis and electrophysiological correlates of vision in the normal and pathological human visual system. It is our hope that this approach will facilitate the understanding and the interest in visual system investigation and assessment.
Article
Full-text available
Objective To provide a rigorous comparison between patients with mild cognitive impairment due to Alzheimer’s disease (MCI-AD) and healthy elderly, as well as to assess the value of electroencephalography (EEG) in terms of early diagnosis, we conducted a neutral image recognition memory task involving individuals with positive biomarkers including β amyloid deposition, pathologic tau or neurodegeneration. Methods The task involving study and test blocks was designed to evaluate participants’ recognition memory. Electroencephalogram was recorded synchronously to elicit event-related potentials in patients with MCI-AD and healthy control subjects. We further analyzed differences between groups or conditions in terms of behavioral performance, time domain, and time-frequency domain. Results The MCI-AD cohort showed a slower response time to old/new images and had low accuracy regarding behavioral performance. The amplitude of the late positive complex for the old/new effects was significantly suppressed in the MCI-AD cohort when compared with that in the HC cohort. The amplitude of the late old/new effects was correlated with the Auditory Verbal Learning Test recognition score in all participants. The time-frequency domain analysis revealed that correct recognition of old items elicited a decrease in beta power, mainly limited to the HC cohort. Moreover, the combination of behavioral (processing speed and accuracy) and electrophysiological (average amplitude and relative power of delta band) measures contributes to classifying patients with MCI-AD from healthy elderly people. Conclusion Changes of old/new effects, accuracy and response time are sensitive to the impairment of recognition memory in patients with MCI-AD and have moderate value in predicting the incipient stage of AD.
Article
Full-text available
Background: Despite increasing interest in the effects of exergaming on cognitive function, little is known about its effects on older adults with dementia. Objective: The purpose of this is to investigate the effects of exergaming on executive and physical functions in older adults with dementia compared to regular aerobic exercise. Methods: In total, 24 older adults with moderate dementia participated in the study. Participants were randomized into either the exergame group (EXG, n=13, 54%) or the aerobic exercise group (AEG, n=11, 46%). For 12 weeks, EXG engaged in a running-based exergame and AEG performed a cycling exercise. At baseline and postintervention, participants underwent the Ericksen flanker test (accuracy % and response time [RT]) while recording event-related potentials (ERPs) that included the N2 and P3b potentials. Participants also underwent the senior fitness test (SFT) and the body composition test pre- and postintervention. Repeated-measures ANOVA was performed to assess the effects of time (pre- vs postintervention), group (EXG vs AEG), and group×time interactions. Results: Compared to AEG, EXG demonstrated greater improvements in the SFT (F1.22=7.434, P=.01), reduction in body fat (F1.22=6.476, P=.02), and increase in skeletal mass (F1.22=4.525, P=.05), fat-free mass (F1.22=6.103, P=.02), and muscle mass (F1.22=6.636, P=.02). Although there was a significantly shorter RT in EXG postintervention (congruent P=.03, 95% CI 13.581-260.419, incongruent P=.04, 95% CI 14.621-408.917), no changes occurred in AEG. EXG also yielded a shorter N2 latency for central (Cz) cortices during both congruent conditions compared to AEG (F1.22=4.281, P=.05). Lastly, EXG presented a significantly increased P3b amplitude compared to AEG during the Ericksen flanker test (congruent: frontal [Fz] F1.22=6.546, P=.02; Cz F1.22=5.963, P=.23; parietal [Pz] F1.22=4.302, P=.05; incongruent: Fz F1.22=8.302, P=.01; Cz F1.22=15.199, P=.001; Pz F1.22=13.774, P=.001). Conclusions: Our results suggest that exergaming may be associated with greater improvements in brain neuronal activity and enhanced executive function task performance than regular aerobic exercise. Exergaming characterized by both aerobic exercise and cognitive stimulation can be used as an effective intervention to improve cognitive and physical functions in older adults with dementia. Trial registration: Clinical Research Information Service KCT0008238; https://cris.nih.go.kr/cris/search/detailSearch.do/24170.
Chapter
Nowadays, swarm intelligence shows a high accuracy while solving difficult problems, including image processing problem. Image Edge detection is a complex optimization problem due to the high-resolution images involving large matrix of pixels. The current work describes several sensitive to the environment models involving swarm intelligence. The agents’ sensitivity is used in order to guide the swarm to obtain the best solution. Both theoretical general guidance and a practical example for a particular swarm are included. The quality of results is measured using several known measures.KeywordsSwarm intelligenceImage processingImage Edge Detection
Article
Full-text available
Face recognition can be facilitated by previous presentation both of the same face and of an associated person’s face. In Experiment 1, the effects of face repetition and associative priming on event-related potentials (ERPs) were compared. Repetition decreased reaction times (RTs) and modulated both early (180–290 ms) and late ERPs beyond 310 ms. Associative priming caused a topographically equivalent late ERP modulation, although RTs and early ERPs were unaffected. The results suggest that repetition acted on an early processing locus, presumably the activation of face representations. Both repetition and associative priming affected a relatively late locus, probably the activation of person-related semantic information. In Experiment 2, face repetitions were omitted and associative priming effects were observed both in ERPs and RTs. This indicates that ERPs may reflect automatic aspects of associative priming more directly than do RTs.
Article
Full-text available
Background: Mild cognitive deficits are more likely to occur with increasing age, and become more pronounced for people diagnosed with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Conventional methods to identify cognitive declines (i.e., neuropsychological testing and clinical judgment) can lead to false positive diagnoses of cognitive impairment. Tools such as electroencephalography (EEG) offer additional measures of cognitive processing, indexing the electrophysiological changes associated with aging, MCI and AD. Objective: We reviewed the literature on EEG to determine if auditory event-related potentials (ERPs) could distinguish between healthy aging, MCI, and AD. Method: We searched two electronic databases (Medline and PyscInfo) for articles published between January 2005 and April 2017. Articles were considered for review if they included: i) participants 60 years of age or older; ii) healthy older adults or those diagnosed with MCI or AD; iii) at least one auditory elicited ERP component. Results: Our search revealed 1532 articles (800 after removing duplicates); 719 were excluded through title/abstract review, and of the 81 remaining articles, 30 satisfied inclusion criteria. All studies compared cognitive function between at least two of the three selected populations. Our findings suggest that the P300 and N200 components may distinguish between healthy cognitive aging, MCI, and AD. Conclusion: ERPs may be sensitive to progressive cognitive changes due to MCI and AD. The P300 and N200 may help identify patients who are likely to progress from MCI to AD, and could be a valuable clinical tool.
Article
Full-text available
In the early stage of Alzheimer disease (AD) or mild cognitive impairment (MCI), working memory (WM) deficiency is prominent and could be attributed to failure in encoding, maintenance or retrieval of information. However, evidence for a retention or retrieval deficit remains equivocal. It is also unclear what cognitive mechanism in WM is impaired in MCI or early AD. We enrolled 46 subjects from our Memory Clinics and community, with 24 amnesic MCI patients and 22 normal subjects. After neurological and cognitive assessments, they performed a classic delayed match to sample (DMS) task with simultaneous event-related potential (ERP) recorded. The ERPs in encoding and retrieval epoch during WM were analyzed separately. The latency and amplitude of every ERP component were compared between two groups, and then analyzed to explore their relationship with neuropsychological performance. Finally, the locations of maximal difference in cortex were calculated by standard low-resolution tomographic analysis. A total of five components were found: P1, N1, P2, N2, and P300. The amplitude of P2 and P300 was larger in normal subjects than in MCI patients only during retrieval, not encoding epoch, while the latency did not show statistical difference. The latency and amplitude of P1 and N1 were similar in two groups. P2 amplitude in the retrieval epoch positively correlated with memory test (auditory verbal learning test) and visual spatial score of Chinese Addenbrooke's Cognitive Examination-Revised (ACE-R), while P300 amplitude correlated with ACE-R. The activation difference in P2 time range was maximal at medial frontal gyrus. However, the difference in cortex activation during P300 time range did not show significance. The amplitude of P2 indicated deficiency in memory retrieval process, potentially due to dysfunction of central executive in WM model. Regarding the location of P2 during WM task, medial frontal plays important role in memory retrieval. The findings in the present study suggested that MCI patients have retrieval deficit, probably due to central executive based on medial frontal gyrus. Thus, it may provide new biomarker for early detection and intervention for aMCI.
Article
Full-text available
Future treatments of Alzheimer's disease need the identification of cases at high risk at the preclinical stage of the disease before the development of irreversible structural damage. We investigated here whether subtle cognitive deterioration in a population of healthy elderly individuals could be predicted by EEG signals at baseline under cognitive activation. Continuous EEG was recorded in 97 elderly control subjects and 45 age-matched mild cognitive impairment (MCI) cases during a simple attentional and a 2-back working memory task. Upon 18-month neuropsychological follow-up, the final sample included 55 stable (sCON) and 42 deteriorated (dCON) controls. We examined the P1, N1, P3, and PNwm event-related components as well as the oscillatory activities in the theta (4-7 Hz), alpha (8-13 Hz), and beta (14-25 Hz) frequency ranges (ERD/ERS: event-related desynchronization/synchronization, and ITC: inter-trial coherence). Behavioral performance, P1, and N1 components were comparable in all groups. The P3, PNwm, and all oscillatory activity indices were altered in MCI cases compared to controls. Only three EEG indices distinguished the two control groups: alpha and beta ERD (dCON > sCON) and beta ITC (dCON < sCON). These findings show that subtle cognitive deterioration has no impact on EEG indices associated with perception, discrimination, and working memory processes but mostly affects attention, resulting in an enhanced recruitment of attentional resources. In addition, cognitive decline alters neural firing synchronization at high frequencies (14-25 Hz) at early stages, and possibly affects lower frequencies (4-13 Hz) only at more severe stages.
Article
Background: Latency of P300 subcomponent of event-related potentials (ERPs) increases in Alzheimer disease (AD) patients, which correlate well with cognitive impairment. Cholinesterase inhibitors (ChEIs) reduce P300 latency in AD patients with parallel improvement in cognition. It is not known whether N200 response to ChEIs is similar to that of P300. The aim of this study was to evaluate and compare characteristics of P300 and N200 in AD patients, treatmentnaïve and on stable donepezil treatment, matched by age, education, sex, and cognitive function. Material/Methods: We recruited 22 consecutive treatment-naïve AD patients (AD-N group), 22 AD patients treated with a stable donepezil dose of 10 mg/day for at least 3 months (AD-T group), and 50 healthy controls were recruited. Neuropsychological testing (MMSE, ADAS-Cog, and additional tests) and ERP recording was performed and analyzed. Results: All groups did not differ according to age, duration of education, or sex (p>0.05). AD-N and AD-T groups did not differ according to cognitive function. The AD-T group had longer duration of disease than the AD-N group (p<0.001). The AD-T and AD-N groups did not differ in P300 latencies (p=0.49). N200 latency was longer in the AD-T group (p<0.001). The general linear model showed that significant predictors of P300 latency were age (p=0.019) and AD treatment status (p<0.001). Duration of AD was a significant predictor of N200 latency (p=0.004). Conclusions: The response of N200 latency to donepezil treatment differs from the response of P300. P300 is a better marker of ChEI treatment-dependent cognitive functions. N200 is more dependent on the duration of AD.
Chapter
Cerebral-evoked potentials reflect the cerebral response to an external stimulus. These potentials may be either obligate responses of the brain to a specific stimulus that occur regardless of the context in which stimulation occurs (stimulus-related potentials) or endogenous responses (i.e., event-related potentials (ERPs)) that occur only when an individual is selectively attentive to a specific external event. This article focuses on the recording and clinical applications of ERPs.
Article
The aim of this study was to investigate the behavioral and electrophysiological dynamics of multiple object processing (MOP) in mild cognitive impairment (MCI) and Alzheimer's disease (AD), and to test whether its neural signatures may represent reliable diagnostic biomarkers. Behavioral performance and event-related potentials [N2pc and contralateral delay activity (CDA)] were measured in AD, MCI, and healthy controls during a MOP task, which consisted in enumerating a variable number of targets presented among distractors. AD patients showed an overall decline in accuracy for both small and large target quantities, whereas in MCI patients, only enumeration of large quantities was impaired. N2pc, a neural marker of attentive individuation, was spared in both AD and MCI patients. In contrast, CDA, which indexes visual short term memory abilities, was altered in both groups of patients, with a non-linear pattern of amplitude modulation along the continuum of the disease: a reduction in AD and an increase in MCI. These results indicate that AD pathology shows a progressive decline in MOP, which is associated to the decay of visual short-term memory mechanisms. Crucially, CDA may be considered as a useful neural signature both to distinguish between healthy and pathological aging and to characterize the different stages along the AD continuum, possibly becoming a reliable candidate for an early diagnostic biomarker of AD pathology.
Article
We examined the effects of amnestic mild cognitive impairment (aMCI) on behavioral (response times and error rates) and scalp-recorded event-related potential (ERP) measures of response execution and inhibition, using Go/NoGo tasks involving basic and superordinate semantic categorization. Twenty-five aMCI (16 F; 68.5±8 years) and 25 age- and gender-matched normal control subjects (16 F; 65.4±7.1 years) completed two visual Go/NoGo tasks. In the single car task, responses were made based on single exemplars of a car (Go) and a dog (NoGo) (basic). In the object animal task, responses were based on multiple exemplars of objects (Go) and animals (NoGo) (superordinate). The aMCI subjects had higher commission errors on the NoGo trials compared to the control subjects, whereas both groups had comparable omission errors and reaction times during the Go trials. The aMCI subjects had significantly prolonged N2 ERP latency during Go and NoGo trials across tasks compared to the controls. Both groups showed similar categorization effects and response type effects in N2/P3 ERP latencies and P3 amplitude. Our findings indicate that altered early neural processing indexed by N2 latency distinguishes subjects with aMCI from controls during the Go/NoGo task. Prolonged Go-N2 latency in aMCI appears to precede behavioral changes in response execution, whereas prolonged NoGo-N2 latency underlies behavioral deterioration in response inhibition.
Article
Background Subjects with a mild cognitive impairment (MCI) have a memory impairment beyond that expected for age and education yet are not demented. These subjects are becoming the focus of many prediction studies and early intervention trials.Objective To characterize clinically subjects with MCI cross-sectionally and longitudinally.Design A prospective, longitudinal inception cohort.Setting General community clinic.Participants A sample of 76 consecutively evaluated subjects with MCI were compared with 234 healthy control subjects and 106 patients with mild Alzheimer disease (AD), all from a community setting as part of the Mayo Clinic Alzheimer's Disease Center/Alzheimer's Disease Patient Registry, Rochester, Minn.Main Outcome Measures The 3 groups of individuals were compared on demographic factors and measures of cognitive function including the Mini-Mental State Examination, Wechsler Adult Intelligence Scale–Revised, Wechsler Memory Scale–Revised, Dementia Rating Scale, Free and Cued Selective Reminding Test, and Auditory Verbal Learning Test. Clinical classifications of dementia and AD were determined according to the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition and the National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer's Disease and Related Disorders Association criteria, respectively.Results The primary distinction between control subjects and subjects with MCI was in the area of memory, while other cognitive functions were comparable. However, when the subjects with MCI were compared with the patients with very mild AD, memory performance was similar, but patients with AD were more impaired in other cognitive domains as well. Longitudinal performance demonstrated that the subjects with MCI declined at a rate greater than that of the controls but less rapidly than the patients with mild AD.Conclusions Patients who meet the criteria for MCI can be differentiated from healthy control subjects and those with very mild AD. They appear to constitute a clinical entity that can be characterized for treatment interventions.