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Asymmetrical cognitive differences associated with hemiparkinsonism
Abstract
The question of whether Parkinson's disease (PD) patients who have left (LPD) or right (RPD) motor predominance also exhibit cognitive differences is controversial. We examined this issue using a neuropsychological battery designed to provide a balanced sampling of both right- and left-hemispheric functions. RPD patients were impaired relative to LPD patients on verbally mediated tasks (left hemisphere function), but there was no group difference for visuospatial tasks (right-hemispheric function). In addition, there was a significant correlation between the extent of right side motor predominance and performance on verbal tasks, but there was no relationship between left side motor symptoms and performance on visuospatial tasks. The controversy related to cognitive differences in hemiparkinsonism may be due to the balance of the assessment procedure, the severity of motor asymmetry, or both.
... As far as neuropsychological functions are concerned, reduced cognitive performances in patients with predominantly right-sided motor symptoms (RPD) have been previously documented in comparison to patients with predominantly left-sided motor symptoms (LPD) (Agosta et al., 2020;Huber et al., 1992;Katzen et al., 2006). These deficits concern global cognitive efficiency (Agosta et al., 2020), long-term verbal memory (Amick et al., 2006;Cubo et al., 2010;Foster et al., 2010;Huber et al., 1992;Starkstein et al., 1987;Starkstein and Leiguarda, 1993), language (Blonder et al., 1989;Mohr et al., 1992;Spicer et al., 1988;Starkstein et al., 1987) and for some specific authors, executive functions (Huber et al., 1992;Voruz et al., 2020;Voruz et al., 2022). ...
... As far as neuropsychological functions are concerned, reduced cognitive performances in patients with predominantly right-sided motor symptoms (RPD) have been previously documented in comparison to patients with predominantly left-sided motor symptoms (LPD) (Agosta et al., 2020;Huber et al., 1992;Katzen et al., 2006). These deficits concern global cognitive efficiency (Agosta et al., 2020), long-term verbal memory (Amick et al., 2006;Cubo et al., 2010;Foster et al., 2010;Huber et al., 1992;Starkstein et al., 1987;Starkstein and Leiguarda, 1993), language (Blonder et al., 1989;Mohr et al., 1992;Spicer et al., 1988;Starkstein et al., 1987) and for some specific authors, executive functions (Huber et al., 1992;Voruz et al., 2020;Voruz et al., 2022). Some have even suggested that RPD patients may be more vulnerable to the onset of dementia associated with PD in the long term (Harris et al., 2013). ...
... As far as neuropsychological functions are concerned, reduced cognitive performances in patients with predominantly right-sided motor symptoms (RPD) have been previously documented in comparison to patients with predominantly left-sided motor symptoms (LPD) (Agosta et al., 2020;Huber et al., 1992;Katzen et al., 2006). These deficits concern global cognitive efficiency (Agosta et al., 2020), long-term verbal memory (Amick et al., 2006;Cubo et al., 2010;Foster et al., 2010;Huber et al., 1992;Starkstein et al., 1987;Starkstein and Leiguarda, 1993), language (Blonder et al., 1989;Mohr et al., 1992;Spicer et al., 1988;Starkstein et al., 1987) and for some specific authors, executive functions (Huber et al., 1992;Voruz et al., 2020;Voruz et al., 2022). Some have even suggested that RPD patients may be more vulnerable to the onset of dementia associated with PD in the long term (Harris et al., 2013). ...
Introduction
The longitudinal trajectories of cognitive-neuropsychiatric symptoms from the early stages of Parkinson's disease, as a function of motor symptom asymmetry at the onset of the disease, remain to be fully explored. Moreover, the relationship to biomarkers warrants further investigation.
Method
ology: Non-motor and biospecimen data from 413 patients with Parkinson's disease, dissociating predominantly left-sided motor symptoms patients (n = 179) and predominantly right-sided motor symptoms patients (n = 234), and matched healthy controls (n = 196), were extracted from the Parkinson's Progression Marker Initiative database during a 3-Year follow-up. Non-parametric and conservative correction for multivariate comparison were carried out on neuropsychiatric and biomarker data.
Results
A decline for global cognitive efficiency scores in predominantly right-sided motor symptoms patients was observed, whereas depressive and anxiety symptoms were greater overtime for predominantly left-sided motor symptoms patients. Biomarkers analysis revealed that predominantly right-sided patients expressed decreased levels of total-tau and phospho-tau over time, while left-sided patients didn't differ from healthy controls.
Conclusion
From the early course of the disease, the existence of different clinical phenotypes is proposed, associated to emerging evidences of distinct pathological pathways and a left-hemispheric vulnerability for cognitive decline.
... Clair et al., reported absence of any difference between the two groups in visuospatial memory, while Huber et al., reported disadvantage for LPD patients on visuospatial memory. [25,26] With regard to visuospatial functions, some previous studies have shown that visuospatial functions are more affected in patients with LPD compared to those with RPD, while another study did not find any difference between the RPD and LPD groups. [9,27] With respect to executive functions, most of the previous studies have used Control Oral Word Association Test (COWAT) and did not find any difference between RPD and LPD groups. ...
... Huber et al., reported poorer verbal span for RPD patients; whereas, Tomer et al., reported a disadvantage for patients in the LPD group. [26,29] Similar findings were obtained in studies using the Visual Span test of the WAIS-R. While one study reported poorer performance in RPD patients, another study did not find any difference between the groups. ...
... While one study reported poorer performance in RPD patients, another study did not find any difference between the groups. [26,30] The discrepancies in the above studies may be due to different neuropsychological tests applied as well as due to inclusion of patients with varying duration of PD. Our study and the study by Erro et al., did not find any difference between the RPD versus LPD, which may be due to the fact that both studies used early PD as the inclusion criteria. ...
Aims:
Though impaired cognition in Parkinson's disease (PD) is well known, data in early PD is sparse. This study was designed to assess the cognitive profile in patients with early PD (motor symptoms <5 years and Hoehn and Yahr stage <2), and to compare the cognitive profile between these patients with right versus left side onset of motor symptoms.
Materials and methods:
National Institute of National Health and Neurosciences (NIMHANS) neuropsychological battery was used to assess the cognitive profile in 50 patients with early PD and compared with 50 age-, education-, and gender-matched healthy controls. Within the PD group, the cognitive profile was also compared between patients with right side onset motor symptoms (RPD) versus those with left side onset (LPD). The neuropsychological tests assessed the executive functions, memory, attention, visuospatial functions, and psychomotor speed.
Results:
Among the 50 patients, 25 each were RPD and LPD. The two subgroups were matched for age, gender, education, age at disease onset, disease duration, and degree of motor disability. There was no significant difference between the groups on Hoehn and Yahr staging or Unified Parkinson Disease Rating Scale (UPDRS) motor score. Patients with early PD performed significantly worse in the tasks involving memory, executive functions, and attention compared to controls. However, there was no difference in the cognitive profile between RPD and LPD subgroups.
Conclusions:
Patients with early PD have cognitive dysfunction with predominant involvement of frontal and temporal lobes. Side of onset of motor symptoms probably does not have significant role in future development or profile of cognitive dysfunction in PD.
... This possibility has been addressed in previous studies, but results have been mixed. A number of studies fully or partially support the expected pattern of lateralized cognitive deficits: PD participants with worse left-sided motor dysfunction perform more poorly on visuospatial (right hemisphere) tasks and those with worse right-sided motor dysfunction perform more poorly on verbally mediated (left-hemisphere) tasks (Amick, Grace, & Chou, 2006; Blonder, Gur, Gur, Saykin, & Hurtig, 1989; Huber, Miller, Bohaska, Christy, & Bornstein, 1992; Spicer, Roberts, & LeWitt, 1988; Starkstein, Leiguarda, Gershanik, & Berthier, 1987; Taylor, Saint-Cyr, & Lang, 1986). Others found widespread cognitive deficits in participants with worse left-sided dysfunction while participants with worse rightsided dysfunction were relatively cognitively spared (Direnfeld et al., 1984; Tomer, Levin, & Weiner, 1993). ...
... Additionally, researchers used different scales for measuring motor deficits and based group inclusion criteria on different aspects of asymmetry, which may contribute to the controversy. For example, some investigators chose to categorize participants according to initial side of symptom onset (Amick et al., 2006; Katzen, Levin, & Weiner, 2006; Tomer et al., 1993) while others used current ratings of absolute motor asymmetry (Barber et al., 1985; Blonder et al., 1989; Riklan et al., 1990); relatively little attention has been paid to the degree of motor asymmetry at the time of cognitive testing (Huber et al., 1992; Tomer et al., 1993). The purpose of this study was to determine whether PD asymmetry affects short term spatial memory performance. ...
Studies suggest motor deficit asymmetry may help predict the pattern of cognitive impairment in individuals with Parkinson disease (PD). We tested this hypothesis using a highly validated and sensitive spatial memory task, spatial delayed response (SDR), and clinical and neuroimaging measures of PD asymmetry. We predicted SDR performance would be more impaired by PD-related changes in the right side of the brain than in the left. PD (n=35) and control (n=28) participants performed the SDR task. PD participants either had worse motor deficits on the right (RPD) or left (LPD) side of the body. Some participants also had magnetic resonance imaging for measurement of their substantia nigra (SN) volumes. The LPD group performed worse on the SDR task than the RPD and control groups. Right SN volume accounted for a unique and significant portion of the variance in SDR error, with smaller volume predicting poorer performance. In conclusion, left motor dysfunction and smaller right SN volume are associated with poorer spatial memory.
... NMS in PD encompass a variety of features, of which cognitive and psychiatric impairments [4], some of which seem to differ based on motor symptom asymmetry [5]. Indeed, from a neuropsychological standpoint, RPD patients seem to show greater cognitive impairment, notably in terms of verbal memory [6,7], language [8], attention [9] and executive functions [10,11]. However, LPD patients seem to be more impaired in the visuospatial domain in comparison to their RPD counterparts [12,13]. ...
Background. Non-motor symptoms are an important early feature of Parkinson’s disease (PD), encompassing a variety of cognitive and psychiatric symptoms that seem to manifest differently depending on motor symptom asymmetry. Different factors, such as uric acid (UA) and sex, seem to influence cognitive and psychiatric expression in PD, however their interplay remains to be better understood.
Methods. Participants taking part in the Parkinson’s Progression Marker Initiative were studied based on the side of motor-symptom asymmetry and sex. Three-way interaction modeling was used to examine the moderating effects of sex and UA on cognitive functions and psychiatric symptoms.
Results. Significant three-way interactions were highlighted at one-year follow-upbetween motor symptom asymmetry, UA and sex for immediate and long-term memory in female patients exhibiting predominantly left-sided motor symptoms, and for processing speed and sleepiness in female patients exhibiting predominantly right-sided motor symptoms. No significant interactions were observed for male patients. Moreover, female patients exhibiting predominantly right-sided motor symptoms demonstrated lower serum UA concentrations and had overall better outcomes, while male patients with predominantly right-sided motor symptoms demonstrated particularly poor outcomes.
Conclusions. These findings suggest that in the earliest stages of the disease, UA and sex moderate cognitive functions and psychiatric symptomsdifferently depending on motor asymmetry, holding important clinical implications for symptom management in patients.
... In this regard, different patterns of NMS have been evidenced in patients presenting predominantly right-sided motor symptoms (RPD; left cerebral hemispheric involvement) in contrast to patients displaying predominantly left-sided motor symptoms (LPD; right cerebral hemispheric involvement). Indeed, RPD patients seem to exhibit greater cognitive impairment, notably regarding verbal memory 8,9 , attention 10 , executive functions 5,11 and language 12,13 . They also demonstrate a more important decline in terms global e ciency scores 4 . ...
Motor symptom asymmetry, a key feature of Parkinson’s disease, has been associated with differences in non-motor symptoms, such as cognitive and neuropsychiatric impairments, and in biomarker profiles. However, the longitudinal relationship between biomarkers and non-motor symptoms as a function of motor symptom asymmetry remains to be fully explored in early-stage patients. Clinical data from the Parkinson’s Progression Marker Initiative was extracted from 179 patients showing predominantly left-sided motor symptoms and 234 patients showing predominantly right-sided motor symptoms during a 3-year follow-up. General estimating equations revealed differential relationships over time between biospecimen and cognitive-neuropsychiatric scores based on motor symptom asymmetry. A more important implication of uric acid and beta-amyloid was noted in patients with predominantly left-sided motor symptoms, whereas patients with predominantly right-sided motor symptoms showed associations with alpha-synuclein and phosphorylated-tau levels. In summary, asymmetry of motor symptoms influences clinical trajectories in early-stage patients, holding important implications for symptom management in this clinical population.
... From a neuropsychological standpoint, RPD patients seem to show greater cognitive impairment, notably in terms of verbal memory 7-9 , language 10,11 , attentional 12 and executive functions 13,14 . However, LPD patients seem to be more impaired in the visuospatial domain in comparison to their RPD counterparts (Karádi et al., 2014;Poletti et al., 2013). ...
The interplay between uric acid, gender, and motor symptom asymmetry in the manifestation of non-motor symptomatology (NMS) remains to be better understood in early-stage Parkinson’s disease (PD). A total of 413 patients taking part in the Parkinson’s Progression Marker Initiative were divided into six groups based on their motor symptom asymmetry and gender. Clinical data was extracted over a 5-year follow-up period. Three-way interaction modeling was used to examine the moderating effects of gender and UA in the relationship between motor symptom asymmetry and NMS. The results highlighted significant moderating effects of uric acid on NMS in female PD patients, but not in male PD patients. Furthermore, female patients with right-sided motor symptom onset demonstrated the most preserved NMS functioning in the presence of lower serum uric acid levels, while their male counterparts showed the most impairment. This holds important clinical implications for symptom management in early-stage PD patients.
... Indeed, the side of onset may have prognostic implications. 86 Moreover, cognitive decline in PD has been associated with left-sided onset of motor features, 87 hinting at an association between laterality of symptom onset and disease progression and severity. Further work is required to better characterize the role of lateralization in PD and possible associated effects of handedness upon disease onset and progression. ...
Vassilios Tahtis,1 Diego Kaski1,2 1Division of Brain Sciences, Imperial College London, Charing Cross Hospital Campus, 2Sobell Department for Motor Control and Movement Disorders, University College London, London, UK Abstract: Parkinson’s disease (PD) is among the most common progressive neurodegenerative conditions worldwide, characterized by bradykinesia, rigidity, tremor, and postural instability, in addition to a variety of cognitive and behavior complications. Current pharmacological treatment options focus on dopaminergic replacement, but these become less efficacious as the disease progresses. Noninvasive brain stimulation techniques have therefore gained favor in recent years as a means of treating the motor and non-motor complications of PD. Here we review the evidence behind the use of transcranial direct current stimulation in the treatment of motor and non-motor complications of PD, discuss the limitations that have hindered the introduction of transcranial direct current stimulation into mainstream clinical practice, and highlight future directions that may enable the translation of this research tool into clinical use. Keywords: Parkinson’s disease, transcranial direct current stimulation, motor, cognitive, non-motor
... Severity of left-and right-sided symptoms were calculated as the sum of the motor examination scores of UPDRS3 evaluating the Parkinsonian symptoms on the left and right extremities (e.g. see Huber et al., 1992). The prevalence of left-and right-sided symptoms were expressed as an asymmetry index (AI), applying the following formula: ...
Parkinson's disease (PD) is often characterized by asymmetrical symptoms, which are more prominent on the side of the body contralateral to the most extensively affected brain hemisphere. Therefore, lateralized PD presents an opportunity to examine the effects of asymmetric subcortical dopamine deficiencies on cognitive functioning. As it has been hypothesized that inhibitory control relies upon a right-lateralized pathway, we tested whether left-dominant PD (LPD) patients suffered from a more severe deficit in this key executive function than right-dominant PD patients (RPD). To this end, via a countermanding task, we assessed both proactive and reactive inhibition in 20 LPD and 20 RPD patients, and in 20 age-matched healthy subjects. As expected, we found that PD patients were significantly more impaired in both forms of inhibitory control than healthy subjects. However, there were no differences either in reactive or proactive inhibition between LPD and RPD patients. All in all, these data support the idea that brain regions affected by PD play a fundamental role in subserving inhibitory function, but do not sustain the hypothesis according to which this executive function is predominantly or solely computed by the brain regions of the right hemisphere.
... Most previous studies revealed no significant differences between LPD and RPD group performance of the digit span test; 12,13 whereas two studies found results similar to ours. 14,15 The 'digit span forward' task has been suggested as being a task of working memory and simple verbal fluency. 16 In RPD, the left hemisphere would presumably be affected more than the right hemisphere would be, given that the cognitive battery weighted on language might be influenced. ...
Background and Purpose
The relationship between the side of motor symptoms and cognitive impairment has rarely been reported in Parkinson’s disease (PD). We aimed to estimate the influence of motor laterality on cognition in PD patients.
Methods
We enrolled 67 patients with PD, and they were divided into two groups according to side of symptom onset or predominant motor symptom presentation (right and left). Right-sided PD (RPD, 40) and left-sided PD (LPD, 27) patients underwent a neuropsychological battery exploring memory, attention/working memory, frontal/executive, visuospatial, and language functions. Student's t-test and Chi-square test have been carried out to compare the clinical and neuropsychological data between two groups.
Results
There were no significant differences in any neuropsychological test between the RPD and LPD groups, except for digit forward span test. RPD patients scored lower on the digit forward span test than LPD patients (5.43±9.49 vs. 6.15±1.38, p=0.045).
Conclusions
RPD patients seem to experience more difficulties in attention and working memory than did LPD patients. The laterality of motor symptoms is not a major determinant for cognitive impairment in PD patients but, we should consider differences of cognitive deficits depending on the side of motor symptoms to treat patients with PD.
... One feature of PD where this distinction has been made before relates to the presenting side of the disorder. The literature suggests that initial right-sided presentation may be associated with particular features including reduced PD severity and a slower rate of progression (Riederer and Sian-Hulsmann, 2012), as well encompassing other disease-related differences (e.g., reduced cognitive deficits; Huber et al., 1992). We tentatively suggest that initial right-sided presentation of motor-related problems in PD may have a further asymmetric associate-deficits in olfactory performance-deficits that are contralateral to the presenting side for motor symptoms, but ipsilateral to the side of the brain initially more affected by the disease. ...
Introduction: Parkinson’s disease (PD) often first presents with asymmetric motor symptoms. A number of studies have now established that sensory deficits can also be similarly asymmetric. It is well established that PD is associated with marked olfactory dysfunction, but whether this too present asymmetrically is a currently contentious question.
Methods: To address this, we recruited 12 early stage Parkinson patients with right-sided motor symptoms and compared them to 12 healthy age-matched controls on tests of olfactory identification and recognition, administered separately to each nostril.
Results: Data analyses indicated that Parkinson patients performed worse with the left nostril on both tasks, while no nostril-related differences were observed for the healthy age-matched control group on the same comparisons.
Conclusion: These findings support the idea that asymmetric deficits do extend into olfactory performance in PD—as they do into other sensory domains—and we examine the possibility that they might be a particular feature of right-sided motor symptom presentation.
... Dopamine neuromodulation is intrinsic to processes of movement and motor learning, cognition, reward processing, food intake, nociception, and endocrine and autonomic regulation. Studies on the lateralization of cognitive functions in patients with PD yielded conflicting results: some reported that neuropsychological deficits are consistent with the lateralization of motor symptoms [4][5][6][7][8][9][10], whilst others failed to find a correlation [11][12][13][14][15]. A limitation of several of these studies is that they prevalently investigated global lateralized brain functions in patients with variable disease severity. ...
Dopamine neurotransmission plays a key role in several brain activities, including motor, cognitive, and behavioral functions. Parkinson's disease (PD) typically begins with asymmetrical motor features related to asymmetrical dopamine denervation. This study was designed to examine whether distinct cognitive, behavioral, and personality features are related to this asymmetry.
Fifty-six patients with mild PD and lateralized motor features were grouped according to dominant side of motor features and evaluated using a neuropsychological assessment focused on attention and executive functions, impulse control disorders, and personality inventory.
There were no differences in neuropsychological functions between patients with right and left lateralized PD, but differences occurred in personality features. Patients with motor impairment predominant on the left-hand side had prevalence of hypomania and conversion profile.
This study suggests that side dominance of dopaminergic denervation may be related to personality features in patients with PD that could influence behavioral aspects.
... Starkstein, Leiguarda, Gershanik, and Berthier (1987) reported significantly poorer performance on the WAIS (verbal and total but not performance) and WCST for PD participants with greater right-side motor severity than PD participants with greater left-side severity. Huber, Miller, Bohaska, Christy, and Bornstein (1992) reported that PD participants with more severe right-side symptoms performed significantly more poorly than left-sided PD participants on tests of intelligence, verbal (but not visual) memory, and concentration. Spicer, Roberts, and LeWitt (1988) reported significantly poorer performance by right-sided PD than left-sided PD on serial digit learning, visual naming, and word fluency tasks. ...
Asymmetric motor severity is common in Parkinson's Disease (PD) and provides a method for examining the neurobiologic mechanisms underlying cognitive and linguistic deficits associated with the disorder. In the present research, PD participants (N=31) were assessed in terms of the asymmetry of their motor symptoms. Interviews with the participants were analyzed with the Linguistic Inquiry and Word Count (LIWC) program. Three measures of linguistic complexity - the proportion of verbs, proportion of function words, and sentence length - were found to be affected by symptom asymmetry. Greater left-side motor severity (and hence greater right-hemisphere dysfunction) was associated with the production of significantly fewer verbs, function words, and shorter sentences. Hence, the production of linguistic complexity in a natural language context was associated with relatively greater right hemisphere involvement. The potential neurobiological mechanisms underlying this effect are discussed.
... Parkinson's disease (PD) typically has an asymmetric onset of motor symptoms (tremor, bradykinesia, rigidity), and this asymmetry, which persists throughout the disease, 1 may reflect asymmetrical nigrostriatal dysfunction. 2 Lateralized cognitive deficits, 3,4 in contrast, are postulated to reflect an asymmetrically decreased cortical dopaminergic tone. 5 Brain atrophy and ventricular enlargement consequent to neurodegenerative cell loss is associated with cognitive deficits in PD. 6,7 The extent to which lateral ventricular enlargement and asymmetries relate to motor symptom asymmetries is unknown, but such a relationship might reasonably be hypothesized, given that the lateral ventricles are surrounded by basal ganglia and downstream structures (thalamus and frontal lobe) affected by PD. ...
Parkinson's disease (PD) typically manifests with asymmetric motor symptom onset. Ventricular enlargement, a nonspecific measure of brain atrophy, has been associated with cognitive decline in PD, but not with motor symptom asymmetry. Asymmetrical ventricular enlargement on magnetic resonance images was explored in a monozygotic twin pair discordant for PD and in nine healthy monozygotic twin pairs. The left-right lateral ventricular volumetric difference of the PD-twin was greater than that of his twin and all other healthy twins, with the larger ventricle observed contralateral to the more symptomatic side. Moreover, the lateral ventricle asymmetry difference between twin pairs was significantly higher for the discordant PD-twin pair than for the healthy twin pairs. This is the first report to suggest the presence of asymmetrical ventricular enlargement in PD, findings that may be worthy of further study.
... of the disease (Gabrieli, Singh et al., 1996; Lewis, Slabosz et al., 2005), perhaps due to altered basal ganglia output or changes in mesocortical dopaminergic pathways (Carbon and Marie, 2003). The degree of impairment in spatial working memory may depend in part on which hemisphere of the brain is more affected by PD, since worse left-sided motor dysfunction in PD is associated with worse spatial (right hemisphere) tasks and worse right-sided motor dysfunction is associated with more impairment on verbally mediated (left-hemisphere) tasks (Taylor, Saint-Cyr et al., 1986; Starkstein, Leiguarda et al., 1987; Spicer, Roberts et al., 1988; Blonder, Gur et al., 1989; Huber, Miller et al., 1992; Amick, Grace et al., 2006). ...
Bilateral subthalamic nucleus deep brain stimulation (STN DBS) can reduce working memory while improving motor function in Parkinson disease (PD), but findings are variable. One possible explanation for this variability is that the effects of bilateral STN DBS on working memory function depend in part on functional or disease asymmetry. The goal of this study was to determine the relative contributions of unilateral DBS to the effects seen with bilateral DBS. Motor (Unified Parkinson Disease Rating Scale Part III, UPDRS) and working memory function (Spatial Delayed Response, SDR) were measured in 49 PD patients with bilateral STN DBS while stimulators were Both-off, Left-on, Right-on and Both-on in a randomized, double-blind manner. Patients were off PD medications overnight. Effects of unilateral DBS were compared to effects of bilateral STN DBS. Mean UPDRS and SDR responses to Left-on vs. Right-on conditions did not differ (p>.20). However, improvement in contralateral UPDRS was greater and SDR performance was more impaired by unilateral DBS in the more affected side of the brain than in the less affected side of the brain (p=.008). The effect of unilateral DBS on the more affected side on contralateral UPDRS and SDR responses was equivalent to that of bilateral DBS. These results suggest that motor and working memory function respond to unilateral STN DBS differentially depending on the asymmetry of motor symptoms.
Background Non-motor symptoms are an important early feature of Parkinson’s disease (PD), encompassing a
variety of cognitive and psychiatric symptoms that seem to manifest differently depending on motor symptom asymmetry.
Different factors, such as uric acid (UA) and sex, seem to influence cognitive and psychiatric expression in PD,
however their interplay remains to be better understood.
Methods Participants taking part in the Parkinson’s Progression Marker Initiative were studied based on the side of
motor symptom asymmetry and sex. Three-way interaction modeling was used to examine the moderating effects of
sex and UA on cognitive functions and psychiatric symptoms.
Results Significant three-way interactions were highlighted at 1-year follow-up between motor symptom asymmetry,
UA and sex for immediate and long-term memory in female patients exhibiting predominantly left-sided motor
symptoms, and for processing speed and sleepiness in female patients exhibiting predominantly right-sided motor
symptoms. No significant interactions were observed for male patients. Moreover, female patients exhibiting predominantly
right-sided motor symptoms demonstrated lower serum UA concentrations and had overall better outcomes,
while male patients with predominantly right-sided motor symptoms demonstrated particularly poor outcomes.
Conclusions These findings suggest that in the earliest stages of the disease, UA and sex moderate cognitive functions
and psychiatric symptoms differently depending on motor asymmetry, holding important clinical implications
for symptom management in patients.
Background
Non-motor symptoms (NMS) are an important early feature of Parkinson’s disease (PD), encompassing a variety of cognitive and neuropsychiatric symptoms, that seem to manifest differently depending on the asymmetry of motor symptoms. Different factors, such as uric acid (UA) and sex, also seem to influence NMS expression in PD. However, the interactions between UA, sex, and motor symptom asymmetry remains to be better understood in PD.
Methods
Participants taking part in the Parkinson’s Progression Marker Initiative were studied based on the side of motor-symptom asymmetry and sex. Three-way interaction modeling was used to examine the moderating effects of sex and UA in time on NMS.
Results
Significant three-way interactions were highlighted at one year follow-up between motor symptom asymmetry, UA and sex, for immediate memory, delayed memory, processing speed and sleepiness for female patients only. Also, female patients exhibiting predominantly right-sided motor symptoms demonstrated the most preserved NMS in the presence of lower serum UA levels.
Conclusion
These findings suggest that in the earliest stages of the disease, serum UA and sex moderate NMS expression differently depending on motor asymmetry. This holds important clinical implications for symptom management in early-stage PD patients.
Background
We previously demonstrated that parietal lobe white matter hyperintensities (WMH) increase the risk for Alzheimer's disease (AD). Here, we examined whether individuals with apolipoprotein E gene (APOE ε4) have increased parietal WMH volume.
Methods
Participants were from the Washington Heights-Inwood Columbia Aging Project (WHICAP; n = 694, 47 with dementia) in northern Manhattan and the Etude Santé Psychologique Prévalence Risques et Traitement study (ESPRIT; n = 539, 8 with dementia) in Montpellier. The association between regional WMH and APOE ε4 was examined separately in each group and then in a combined analysis.
Results
In WHICAP, ε4 carriers had higher WMH volume particularly in parietal and occipital lobes. In ESPRIT, ε4 carriers had elevated WMH particularly in parietal and temporal lobes. In the combined analysis, ε4 carriers had higher WMH in parietal and occipital lobes. Increased WMH volume was associated with increased frequency of dementia irrespective of APOE ε4 status; those with the ε4 were more likely to have dementia if they also had increased parietal WMH.
Conclusions
APOE ε4 is associated with increased parietal lobe WMH.
The destruction of the dopaminergic neurons in the substantia nigra (SN) and consequent depletion of striatal dopamine elicits the main movement deficits related to Parkinson's disease (PD). In the early stages of the illness, the motor symptoms are often exhibited asymmetrically. Thus, the onset of PD features starts on either the right or left side. The side of onset appears to determine the prognosis of the disorder and other features, such as right-side tremor dominance has a better prognosis in contrast to left-side dominant bradykinesia-rigidity. In addition, left-side onset of motor features is associated with cognitive decline. Therefore, an intricate relation appears to exist between the side of disease onset and progression/severity and other non-motor symptoms. Unilateral PD in turn corresponds to neuronal nigrostriatal degeneration in the contralateral hemisphere. Indeed positron emission tomography has demonstrated a positive correlation between symptom asymmetry and brain function (Hoorn et al. Parkinsonism Relat Disord 17:58-60, 2011), which corresponds to a unilateral pattern of degeneration. This phenomenon appears to be exclusive to PD. Additionally, the variation in motor symptom(s) dominance exhibited in the disorder conforms to the notion that PD is a spectrum disease with many sub-groups. Thus, clinical and post mortem studies on "lateralisation" may serve as a vital tool in understanding the mechanism(s) eliciting the characteristic destruction of the SN neurons. Additionally, it may be employed as a predictive indicator for the symptomology and prognosis of the illness thus allowing selective treatment strategies targeted at the pronounced hemispheric degeneration.
At disease onset, patients with Parkinson's disease (PD) typically report one side of the body to be more affected than the other. Previous studies have reported that this motor symptom asymmetry is associated with asymmetric dopaminergic degeneration in the brain. Research on the cognitive repercussions of this asymmetric degeneration has yielded inconsistent results. Here, we review studies that reported on the cognitive performance of patients with left-sided (LPD) or right-sided (RPD) motor symptom predominance. We present evidence that patients with RPD typically experience problems with language-related tasks and verbal memory, whereas patients with LPD more often perform worse on tasks of spatial attention, visuospatial orienting and memory and mental imagery. In general, no differences were found between both groups on tasks measuring attention and executive function. The association between motor asymmetry and cognitive performance indicates that PD does not lead to one typical cognitive profile. The effect of symptom laterality on the cognitive complaints should be considered in the assessment and treatment of each individual patient.
This investigation sought to study immediate and delayed verbal and visuospatial recall in Parkinson disease (PD) patients with left hemibody (LHO) and right hemibody (RHO) onset of motor symptoms and to examine the role of mental processing speed in recall of this information.
Research is mixed regarding material specific memory impairments in LHO and RHO PD. However, earlier research has not used a factorial approach in investigating material specific memory in LHO and RHO PD. We hypothesized that LHO PD patients would exhibit an increase in performance following the delayed verbal free recall trial and either decline or stability in performance on the delayed visuospatial free recall trial. The opposite pattern was hypothesized for RHO PD patients.
The Hopkins Verbal Learning Test-revised (HVLT-R) and the Brief Visuospatial Memory Test-revised (BVMT-R) were administered to a sample of 28 LHO PD patients and 36 RHO PD patients. The Stroop Color-word Test was administered as a measure of mental processing speed.
The results indicated that the RHO group experienced a significant decline in performance on verbal free recall from the immediate to the delayed trials and a significant improvement in performance from the immediate to the delayed visuospatial free recall trials. Additionally, a significant negative correlation was found between mental processing speed and changes in recall from the immediate to the delayed conditions for the RHO group.
These results indicate that the RHO PD group experienced a significant decline in verbal free recall and a significant improvement in visuospatial free recall from the immediate to the delayed trials and that the LHO PD patients experienced no significant changes. Further, mental processing speed appears to influence the recall of information from the immediate to the delayed conditions.
Visual-spatial disembedding requires a person to visually scan the stimulus and allocate spatial selective attention to the locations of relevant stimuli. Parkinson's disease (PD) is often associated with visual-spatial deficits, but the influence of PD on disembedding is not entirely known. The goal of this study is to learn whether participants with PD have defective visuospatial disembedding and whether this defect responds to dopaminergic treatment. We also wanted to examine the relationship of disembedding with other cognitive processes and the different parkinsonian clinical symptoms. Participants were PD patients and matched controls. PD participants were tested "on" and "off" medications on the Hidden Patterns Test (HPT) and tests of frontal-executive functions. PD patients had difficulties in visual-spatial disembedding that were not related to medication status, illness duration or severity, or symptom presentation, but were related to other tasks requiring visual scanning in response to alterations in spatial allocation of attention. Lack of improvement with dopaminergic treatment suggests deficits in other neurotransmitter-neuromodulatory systems or degenerative processes in the frontal-striatal networks, cortex, or basal ganglia.
Studies attempting to relate cognitive impairment to asymmetry of motor symptoms in Parkinson's disease (PD) have found contradictory results. We examined 88 patients with unilateral onset of idiopathic PD who underwent a comprehensive neuropsychological assessment, including language, visuospatial abilities, abstraction and reasoning, attention and mental tracking, set shifting, and memory. Patients whose motor signs began on the left side of the body consistently performed more poorly on the battery of cognitive measures than did patients with right-side onset. Significant differences were found on immediate and delayed verbal recall, word retrieval, semantic verbal fluency, visuospatial analysis, abstract reasoning, attention span, and mental tracking. These differences could not be attributed to differences in the overall severity of motor symptoms at the time of cognitive assessment, or the current pattern of motor asymmetry. This finding suggests that damage to right-hemisphere dopamine systems plays a disproportionately greater role in PD-related cognitive decline than a presumably comparable left-hemisphere dopamine depletion.
Parkinsonians with predominantly unilateral signs provide an interesting experimental means to evaluate if asymmetric nigro-striatal degeneration may affect neuropsychological functions. The aim of our study was to establish if the side of onset of idiopathic Parkinson's disease, right (PDR) or left (PDL), determines a selective pattern of cognitive performances. Furthermore, we verified if PDR and PDL groups show a different frequency of dementia. PDR and PDL patients with at least seven years of disease duration, matched for age, schooling, severity of extrapyramidal symptomatology and index of lateralization, were evaluated by using an extensive neuropsychological battery aimed at assessing hemispheric cognitive asymmetries. Current side of greater motor impairment was the same as the one affected at the onset of the disease.
Only subtle differences in the profile of neuropsychological dysfunction emerged from the comparison of PDR and PDL subjects. Moreover, the number of parkinsonians showing dementia syndrome was the same in both groups. Our results suggest that the side of onset of motor impairment does not significantly influence the cognitive performances in PD. Subcortical anatomic and/or functional asymmetries seem to play a less important role in the intellectual functions than in motor activities.
Eleven patients with Parkinson's disease (PD) and predominantly right-sided motor signs, 12 patients with PD and predominantly left-sided signs, and 11 demographically matched healthy controls were compared on tests assessing a range of cognitive and affective functions. Assuming a novel approach, our test battery was composed of measures drawn from ones previously used in the hemiparkinson' s disease and lateralized PD literature. The two patient groups were similar in illness duration, severity of motor signs, and degree of lateralized motor deficits. Statistical analyses did not reveal significant differences between patient groups, consistent with other studies that have failed to find differences in neuropsychological functioning between PD patients with right- and left-sided motor signs.
Non-demented patients with Parkinson's disease (PD), especially if they are high functioning and early in the course of their disease, usually exhibit mild deficits in anterograde recall memory for verbal and non-verbal material, visuospatial reasoning, visuomotor construction, temporal ordering and sequencing. Impairments in problem solving and verbal fluency tests may also occur. PD patients with predominantly right-sided symptoms usually exhibit more severe difficulties with verbal than with non-verbal tasks. We report a case of a highly educated right-handed man with very mild right-sided hemiparkinsonism who never received anti-Parkinsonian or other psychoactive medication. Our patient showed anterograde and retrograde amnesia for faces and spatial locations and difficulties on complex visuospatial tasks that required manual responses, but normal to above average performance on all other cognitive tests. The specific pattern of cognitive loss early in PD may depend on which spatial, facial or verbal pre-frontal striatal circuits are deprived of their dopaminergic inputs.
The aetiology of the cognitive changes seen in Parkinson's disease (PD) is multifactorial but it is likely that a significant contribution arises from the disruption of dopaminergic pathways. This study aimed to investigate the contribution of the dopaminergic system to performance on two executive tasks using (18)F-6-fluorodopa positron emission tomography ((18)F-dopa PET) in PD subjects with early cognitive changes.
16 non-demented, non-depressed PD subjects were evaluated with the Tower of London (TOL) spatial planning task, a verbal working memory task (VWMT) and (18)F-dopa PET, all known to be affected in early PD. Statistical parametric mapping (SPM) localised brain regions in which (18)F-dopa uptake covaried with performance scores. Frontal cortical resting glucose metabolism was assessed with (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET.
SPM localised significant covariation between right caudate (18)F-dopa uptake (Ki) and TOL scores and between left anterior putamen Ki and VWMT performance. No significant covariation was found between task scores and (18)F-dopa Ki values in either limbic or cortical regions. Frontal cortical glucose metabolism was preserved in all cases.
These findings support a causative role of striatal dopaminergic depletion in the early impairment of executive functions seen in PD. They suggest that spatial and verbal executive tasks require integrity of the right and left striatum, respectively, and imply that the pattern of cognitive changes manifest by a patient with PD may reflect differential dopamine loss in the two striatal complexes.
It is well known that many patients with Parkinson's disease experience neuropsychological decline. However, the nature and extent of mental status change varies widely, with some patients showing mild or no cognitive impairments and others exhibiting frank dementia. Research has shown that several clinical disease parameters may differentially correlate with patterns of neuropsychological dysfunction. The present study examined side and type of motor symptom at disease onset and their relationship to cognition in idiopathic Parkinson's disease (PD). We identified 58 patients who initially presented with one of the following symptom profiles: right-side tremor onset (RSO-T; n = 15), right-side bradykinesia/rigidity onset (n = 12), left-side tremor onset (n = 19), and left-side bradykinesia/rigidity onset (n = 12). There were no differences between groups in disease duration, overall mental status, education, or depression severity. We administered a battery of neuropsychological measures to the four PD subgroups and a group of matched control subjects (n = 40). MANCOVAs controlling for age revealed patients with RSO-T performed significantly better than the other three PD subgroups across the entire neuropsychological battery. Further, the RSO-T subgroup performed comparably to controls. In contrast, the other three PD subgroups showed widespread cognitive deficits. These findings suggest an intricate relationship between motor symptom and side of disease onset and it is the combination of these factors that may influence the disease course and extent of cognitive deterioration. Furthermore, patients who develop tremor on the right side of their body represent a distinct subgroup of PD patients who exhibit relative sparing of cognitive function.
A clinical method for noninvasive measurement of regional cerebral blood flow (rCBF) and blood volume (rCBV) is described, based on Obrist's 10 minute, desaturation method after 1 minute inhalation of 133Xe. Sixteen collimated probes are placed over both hemispheres and brain stem-cerebellar regions. End-tidal 133Xe curves are used for correction of recirculation. KEV discriminators are set to record gamma and x-ray activity separately. Values are printed out automatically by a computer on a brain map. Extracerebral contamination is reduced by 1) computing curves from gamma activity, 2) applying pressure on the scalp beneath the probes, 3) 1 minute inhalation of 133Xe and recording desaturation curves for 10 minutes, thereby minimizing slow clearance from extracranial tissues. Normal values for both fast and slow compartments are reproducible and are in good agreement with the carotid injection method. The speech dominant hemishpere has higher flow than the right under conditions described. Posterior portions of the cranium over the cerebellum and brain stem appear to have higher flow gray values than the cerebral cortex. Gray matter flow decreases with advancing age.
Recent studies have documented the presence of neglect in patients with subcortical lesions. In this study, we gave 31 patients with Parkinson's disease (14 bilateral, seven right sided and ten left sided) a visual cancellation test. Visual neglect was found only in the bilateral and left-sided parkinsonian patients. These data support the hypothesis that subcortical structures are involved in attentional mechanisms and indicate the dominance of the right hemisphere for these mechanisms.
The distribution of gray matter in the two cerebral hemispheres was determined by the xenon-133 inhalation method. There was more gray matter relative to white matter in the left hemisphere than in the right, particularly in the frontal and precentral regions. This finding suggests that the organization of the left hemisphere, relative to that of the right, emphasizes processing or transfer within regions, or both, rather than transfer across regions.
1. Dementia: Significance, Definition, and Epidemiology 2. Mental Status Assessment 3. Diagnosis of Dementia 4. Alzheimer's Disease 5. Vascular Dementia 6. Frontotemporal Dementia and the Asymmetric Cortical Atrophies 7. Parkinsonian Disorders with Dementia 8. Non-Parkinsonian Motor Disorders with Dementia 9. Dementia from Conventional Infectious Agents 10. Creutzfeldt-Jakob Disease and Other Prion Disorders 11. Toxic-Matabolic Causes of Dementia 12. Psychiatric Dementias Associated with Psychiatric Disorders 13. Miscellaneous Dementia Syndromes 14. Pharmacotherapy of Alzheimer's Disease and Other Dementias 15. Non-Pharmacologic Management of Dementia 16. Conclusions and Directions Index
Studies of sensory and motor capacities of the hands in brain-injured subjects indicate that, contrary to the prevailing view, these capacities are represented differently in the two hemispheres, tending to be focally represented in the left hemisphere but diffusely represented in the right. This difference between the hemispheres was found not only for contralateral sensorimotor function, but also for ipsilateral; moreover, such a difference seemed to apply not only to these relatively simple manual capacities, but to more complex abilities as well. The two contrasting modes of neural organization, which appear to be linked to the hemisphere rather than to the particular hand or level of function involved, provide a possible clue to the mechanism of hemispheric specialization. More specifically, it is proposed that focal representation of elementary functions in the left hemisphere favors integration of similar units and consequently specialization for behaviors which demand fine sensorimotor control, such as manual skills and speech. Conversely, diffuse representation of elementary functions in the right hemisphere may lead to integration of dissimilar units and hence specialization for behaviors requiring multimodal coordination, such as the various spatial abilities.
The purpose of this investigation is to determine the normal values for regional cerebral blood flow (rCBF) as determined by the xenon inhalation method of Obrist. Normal values for all rCBF parameters were measured in 15 healthy individuals. Our data are compared with the normal data obtained by other investigators. In addition, test-retest rCBF measurements were performed to determine the reproducibility of the method. Our results show that the method is highly reproducible when carried out in serial studies over a short period of time.
Seven dextral patients with Parkinson's disease (PD) who had predominant right-sided motor signs were compared on neuropsychological tests with eight dextral patients with PD who had predominant left-sided signs. Objective criteria for group designation were developed from clinical ratings. The patient subgroups were matched on age, education, estimated premorbid IQ, severity of motor signs, and medication usage. Patients with signs lateralized to the right were more impaired on tests of dominant hemisphere function (serial digit learning, confrontation naming, and verbal associative fluency), but no differences were found on tests of nondominant hemisphere function (form sequence learning, line orientation, facial recognition), indicating some correlation of neuropsychological performance with lateralization of predominant motor signs. Findings demonstrate that the cognitive deficits (particularly visuospatial) previously reported in the literature are not seen consistently in all subjects with PD.
The relationship between severity of disease, intellectual impairment, and depression was examined in 50 patients with Parkinson's disease. A significant correlation between severity of disease and intellectual impairment suggests that both may result from the same subcortical lesions. Depression was not significantly related either to severity of disease or to intellectual impairment. This suggests that the relationship between severity of disease and intellectual impairment was not an artifact of increasing depression. Severity of rigidity and of bradykinesia did predict severity of intellectual decline, but severity of tremor predicted better intellectual status. Patients with a predominance of tremor may have a more benign clinical course as well as better intellectual function than patients with a predominance of rigidity and bradykinesia.
This study examined the performance of groups of patients (n = 97) with independently localized cerebral lesions on the Verbal Concept Attainment Test (VCAT). It was found that the left frontal group was impaired relative to all the other-lesion groups. In addition frequency distributions were examined in the lesion groups and a large normative sample (n = 360). Although the means of the other-lesion groups were below that of controls, the left frontal group had the lowest mean score, and was characterized by an absence of relatively good scores. Possible cut-off scores were examined for potential clinical utility. The data were discussed in relation to previous studies of frontal-lobe behavioral deficits and in relation to the potential clinical utility of the VCAT in detection of frontal-lobe dysfunction.
The performance of patients with Parkinson’s disease was compared with that of controls on two types of tests of motor ability: repetitive tapping of a button for a ten-second period of time and tracking a light moving at random on a screen. The performance of patients with parkinsonism was significantly worse than the controls on both types of tests. The response to the tests differed, however, depending on whether the patient’s major motor symptoms predominated on the left or right side of the body or were equal on both sides of the body. Patients with primarily right-sided symptoms (inferred left hemispheric dysfunction) had bimanual alterations in both the tapping and the tracking tasks. Patients with primarily left-sided symptoms (inferred right hemispheric dysfunction) performed significantly worse than the controls on the tapping test, only with the hand contralateral to the major brain damage. However, in the tracking task, where a visuospatial factor was required, the group with left-sided symptoms (right hemispheric dysfunction) was more impaired. The findings are discussed in relation to asymmetries of cerebral function produced as a result of subcortical disease.
Conducted this study to cross-validate the Verbal Concept Attainment Test as a measure of potential value in neuropsychological assessment and to validate a booklet form of this test. Two samples of 75 patients referred for neuropsychological examination were studied. In both samples the pattern of relationship between the VCAT and a number of widely used neuropsychological measures closely paralleled the pattern reported in the initial validation study. The pattern of relationships with the booklet form was also very similar to the pattern of relationships between the neuropsychological measures and the Impairment Index from the Halstead-Reitan Battery. It was concluded that these data provided evidence of the stability of this test across samples and that the booklet form appeared to be an equally valid measure.
Unilateral neglect reflects a disturbance in the spatial distribution of directed attention. A review of unilateral neglect syndromes in monkeys and humans suggests that four cerebral regions provide an integrated network for the modulation of directed attention within extrapersonal space. Each component region has a unique functional role that reflects its profile of anatomical connectivity, and each gives rise to a different clinical type of unilateral neglect when damaged. A posterior parietal component provides an internal sensory map and perhaps also a mechanism for modifying the extent of synaptic space devoted to specific portions of the external world; a limbic component in the cingulate gyrus regulates the spatial distribution of motivational valence; a frontal component coordinates the motor programs for exploration, scanning, reaching, and fixating; and a reticular component provides the underlying level of arousal and vigilance. This hypothetical network requires at least three complementary and interacting representations of extrapersonal space: a sensory representation in posterior parietal cortex, a schema for distributing exploratory movements in frontal cortex, and a motivational map in the cingulate cortex. Lesions in only one component of this network yield partial unilateral neglect syndromes, while those that encompass all the components result in profound deficits that transcend the mass effect of the larger lesion. This network approach to the localization of complex functions offers an alternative to more extreme approaches, some of which stress an exclusive concentration of function within individual centers in the brain and others which advocate a more uniform (equipotential or holistic) distribution.
The pathologic changes of parkinsonism and the side effects of drug therapy may produce pronounced behavioral changes in patients with Parkinson's disease. Dementia is the primary manifestation of disease-induced mental alterations and careful pharmacologic management is necessary. Psychosis is the most dramatic of the changes induced by levodopa. It may occur early in the course of therapy, usually in patients with a past history of a schizophreniform disorder, or after several years of treatment. Therapeutic intervention with dosage adjustments and/or drug holidays are indicated when psychosis occurs. Treatment of depression in the Parkinson patient is essentially the same as in a nonparkinson patient.
We studied 60 patients with idiopathic Parkinson disease with motor and neuropsychologic tests to ascertain whether the severity of motor symptoms was associated with the degree of neuropsychologic deficity. Significant correlations were found between the severity of brady kinesia and impaired performance on tests assessing visual-spatial reasoning and psychomotor speed. More severe tremor was associated with better performance on a spatial orientation memory test. There relationships remained when age, age at onset, and self-rated depression were controlled. The findings suggested that cognitive impairment may result from the same subcortical lesions that cause motor symptoms.
We measured the concentrations of dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid in several cortical areas from controls and parkinsonian patients. Substantial amounts of dopamine and its metabolites were detected in hippocampus and entorhinal, cingulate, and frontal cortex of controls. In parkinsonian patients the levels of dopamine and its metabolites were reduced in these neocortical areas and hippocampus. Diminution of cortical dopaminergic transmission may play a role in the mental impairment of some Parkinson patients.
123 normal adults and 107 patients with focal and diffuse cerebral lesions were administered the Wisconsin Card Sorting Test (WCST) and the Halstead-Reitan Neuropsychological Test Battery (HRTB). Significant differences were found between the neurologically normal group and the total brain-damaged sample on WCST perseverative responses. Among brain-damaged groups, frontal groups were significantly more impaired than nonfrontal groups on perseverative responses but were not more impaired than a diffuse group, even when generalized neuropsychological impairment was controlled. Two discriminant functions were developed to assess the utility of the perseverative response measure in classifying individual frontal and nonfrontal cases in conjunction with demographic and HRTB variables. Results suggest that the WCST is a clinically useful tool for discriminating frontal from nonfrontal lesions and a better single discriminant than any test currently in the HRTB. (15 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
~c~fer Me~rtcr), &de -reuised
- D Wechsjer
WechsJer, D. (1987). ~c~fer Me~rtcr), &de -reuised. New York Warcourt Brace Jovanovich.
Diiturbance of recent memos function in ~~oso~~ patienntf on anti-chofinergic therapy. Correx
- W C Kober
KoBer, W. C. (1984). Diiturbance of recent memos function in ~~oso~~ patienntf on anti-chofinergic therapy. Correx, Z&307-3 11.
Fmntjl tohe d~sfuo~tio~ in Parkinson's dis-ease: The cortical focus of neostriatai outflow
- A E Taylor
- J A Saint-Cyr
- A E Lange
Taylor, A. E., Saint-Cyr, J. A., & Lange, A. E. (1986) Fmntjl tohe d~sfuo~tio~ in Parkinson's dis-ease: The cortical focus of neostriatai outflow. Brain, 190,%&-883.
Wisconsin Card Sorting Test Manual. Oderson, n: Psycbologicaf Assessment Resources
- R K S J Heaton
- Huber
Heaton, R. K. (1981). Wisconsin Card Sorting Test Manual. Oderson, n: Psycbologicaf Assessment Resources. S. J. Huber et al.
Ne~opsychalu~~c~ distnr-bances in he~~~~s disease
- S St&stein
- R Leiguarda
- . Gerskmik
- M I% Berthier
St&stein, S., Leiguarda, R., Gerskmik, 0.. I% Berthier, M. (1987). Ne~opsychalu~~c~ distnr-bances in he~~~~s disease, Neurology, 37,2X2-1764.
Projection technique far evafttating surgery in P~~~on~s disease T&K?' ~~~~~s~~ QZ 'ar.Urrori's &ens& ~~mb~gb: Liviugstono
- R S Schwab
- A C Errgland
Schwab, R. S., & Errgland, A. C. (1969). Projection technique far evafttating surgery in P~~~on~s disease. In F. f, ~1~:~~~ & I. M. L, Doualdaon (&Is.), T&K?' ~~~~~s~~ QZ 'ar.Urrori's &ens& ~~mb~gb: Liviugstono, 152-157.
A cortical network for directed aWnlion and uitihtend ne@ect
- M M Mesuiam
Mesuiam, M. M. (1981). A cortical network for directed aWnlion and uitihtend ne@ect. Ann& Neumlag)t, IQ, 309-32s.
Viiuospatial impairments in Parkinson's disease
- F Boller
- D Passatiwne
- N C Keefe
- K Rogers
- L Morrow
- Y Kim
Boller, F., Passatiwne, D., Keefe, N. C., Rogers, K., Morrow, L., & Kim, Y. (1984). Viiuospatial impairments in Parkinson's disease. Archives Neurology, 41,48.5-490.