Executive dysfunction in Parkinson’s disease: A meta-analysis on the Wisconsin Card Sorting Test literature

Changes of neural coupling between cognitive and motor networks associated with dual-task performance in Parkinson's disease

BACKGOUND

Although cognitive control is essential for efficient gait, the associations between cognitive and motor networks regarding gait in individuals with Parkinson's disease (PD) remain to be determined. Herein, we enrolled 28 PD and 28 controls to compare internetwork coupling among cognitive and motor networks and examine its relationship with single- and dual-task gait performance in PD.

METHODS

The dorsal attention network (DAN), left and right frontoparietal control networks (FPNs), sensorimotor network, and lateral motor network were identified using resting-state functional magnetic resonance imaging data. The time taken to complete a 10-m walk test during cognitive or physical dual-tasks in PD was calculated representing gait performance.

RESULTS

We observed that the internetwork couplings between the DAN and motor networks and between the motor networks decreased whereas those between the left FPN and DAN and motor networks increased in PD compared to controls using a permutation test. There was no significant correlation between the internetwork couplings and single- and dual-task gait performance in PD. Nevertheless, improved cognitive dual-task performance showed a positive correlation with the DAN and left FPN coupling and a negative correlation with the DAN and lateral motor network coupling in a good performance group. The opposite relationship was observed in the poor cognitive dual-task performance group.

CONCLUSION

Our findings suggest a neural mechanism of cognitive control on gait to compensate for reduced goal-directed attention in PD who maintain cognitive dual-task performance.

Executive function and adult homelessness, true impairment or frontal lobology?

Homelessness is associated with multiple risk factors for neurocognitive impairment. Past research with people experiencing homelessness has described "frontal lobe" dysfunction including behavioral disorders and executive cognitive impairments. In the current study, 72 adults experiencing homelessness were assessed with a standardized assessment of executive function, and interviewed regarding neurological and psychiatric history. When compared to a control sample of 25 never-homeless participants, and controlling for level of education, there was little evidence for executive dysfunction in the sample of people experiencing homelessness. Levels of substance abuse, past head injury, and post-traumatic stress disorder were notably high. However, there were no statistically significant associations between cognitive task performance and clinical or substance abuse variables. Gambling was surprisingly infrequent, but risk-taking behavior among intravenous drug users was common. Though in neither case was it linked to executive function. Overall, there was little evidence for executive impairment in this sample of people experiencing homelessness. I suggest that past research has often used inappropriate criteria for "normal" performance, particularly comparing people experiencing homelessness to control data of relatively high education level. This has led to elements of "frontal lobology," that is, clinical neuroscience research that tends to overly link non-typical or pathological behavior to frontal lobe impairment. When appropriate comparisons are made, controlling for education level, as in this study, associations between executive function impairments and adult homelessness may be weaker than previously reported.

Evaluating cognitive impairment in the early stages of Parkinson's disease using the Cambridge brain sciences-cognitive platform

BACKGROUND

Non-motor symptoms (NMS) such as cognitive impairment are among common presentations in patients with Parkinson's disease (PD). In parallel with motor symptoms, these impediments can affect PD patients' quality of life. However, cognitive impairment has received less attention in early PD. On the other hand, the relationship between olfactory symptoms and cognitive impairment is unclear in early PD. Considering the importance of accurate and timely assessment of cognitive function in PD patients using readily available/validated tests, this study has employed the Cambridge Brain Sciences-Cognitive Platform (CBS-CP) as a computer-based tool to assess cognitive presentations in early PD patients.

METHODS

Thirty-four eligible males and females were assigned to PD and healthy controls (HCs). The cognitive performance was assessed using CBS-CP and Mini-Mental State Examination (MMSE), and olfactory function was measured through the standardized olfactory Quick Smell test (QST).

RESULTS

PD patients had poorer performance in all CBS-CP tasks, including short-term memory, attention, and reasoning domains than HCs. Meanwhile, the verbal domain task scores showed no significant difference between groups. PD MMSE results were in the normal range (mean=26.96), although there was a significant difference between the PD and HCs groups (P = 0.000). Our results revealed no correlation between cognitive impairment and olfactory function in PD patients.

CONCLUSION

Given the widely studied features of CBS-CP and its reliability across published evidence, CBS-CP appears to be a suitable measurement to evaluate cognitive impairment in early PD with normal MMSE scores. It seems cognitive and olfactory impairments are independent in early PD.

DATA AVAILABILITY STATEMENT

The datasets generated during the current study are available from the corresponding author upon reasonable request.

Dopaminergic and norepinephrinergic modulation of endogenous event-related potentials: A systematic review and meta-analysis

Event-related potentials (ERPs) represent the cortical processing of sensory, motor or cognitive functions invoked by particular events or stimuli. A current theory posits that the catecholaminergic neurotransmitters dopamine (DA) and norepinephrine (NE) modulate a number of endogenous ERPs during various cognitive processes. This manuscript aims to evaluate a leading neurotransmitter hypothesis with a systematic overview and meta-analysis of pharmacologic DA and NE manipulation of specific ERPs in healthy subjects during executive function. Specifically, the frontally-distributed P3a, N2, and Ne/ERN (or error-related negativity) are supposedly modulated primarily by DA, whereas the parietally-distributed P3b is thought to be modulated by NE. Based on preceding research, we refer to this distinction between frontally-distributed DA-sensitive and parietally-distributed NE-sensitive ERP components as the Extended Neurobiological Polich (ENP) hypothesis. Our systematic review and meta-analysis indicate that this distinction is too simplistic and many factors interact with DA and NE to influence these specific ERPs. These may include genetic factors, the specific cognitive processes engaged, or elements of study design, i.e. session or sequence effects or data-analysis strategies.

Laterality in Parkinson's disease: A neuropsychological review

Laterality of motor symptom onset in Parkinson's disease is both well-known and under-appreciated. Treatment of disorders that have asymmetric pathological features, such as stroke and epilepsy, demonstrate the importance of incorporating hemispheric lateralization and specialization into therapy and care planning. These practices could theoretically extend to Parkinson's disease, providing increased diagnostic accuracy and improved treatment outcomes. Additionally, while motor symptoms have generally received the majority of attention, non-motor features (e.g., autonomic dysfunction) also decrease quality of life and are influenced by asymmetrical neurodegeneration. Due to the laterality of cognitive and behavioral processes in the two brain hemispheres, analysis of hemibody side of onset can potentially give insight into expected symptom profile of the patient and allow for increased predictive accuracy of disease progression and outcome, thus opening the door to personalized and improved therapy in treating Parkinson's disease patients. This review discusses motor and non-motor symptoms (namely autonomic, sensory, emotional, and cognitive dysfunction) of Parkinson's disease in respect to hemispheric lateralization from a theoretical perspective in hopes of providing a framework for future research and personalized treatment.

EEG-Based Mapping of Resting-State Functional Brain Networks in Patients with Parkinson's Disease

(1) Background: Directed functional connectivity (DFC) alterations within brain networks are described using fMRI. EEG has been scarcely used. We aimed to explore changes in DFC in the sensory-motor network (SMN), ventral-attention network (VAN), dorsal-attention network (DAN), and central-executive network (CEN) using an EEG-based mapping between PD patients and healthy controls (HCs). (2) Methods: Four-minutes resting EEG was recorded from 29 PD patients and 28 HCs. Network’s hubs were defined using fMRI-based binary masks and their electrical activity was calculated using the LORETA. DFC between each network’s hub-pairs was calculated for theta, alpha and beta bands using temporal partial directed coherence (tPDC). (3) Results: tPDCs percent was lower in the CEN and DAN in PD patients compared to HCs, while no differences were observed in the SMN and VAN (group*network: F = 5.943, p < 0.001) in all bands (group*band: F = 0.914, p = 0.401). However, in the VAN, PD patients showed greater tPDCs strength compared to HCs (p < 0.001). (4) Conclusions: Our results demonstrated reduced connectivity in the CEN and DAN, and increased connectivity in the VAN in PD patients. These results indicate a complex pattern of DFC alteration within major brain networks, reflecting the co-occurrence of impairment and compensatory mechanisms processes taking place in PD.

Acute improvement in the attention network with repetitive transcranial magnetic stimulation in Parkinson's disease

PURPOSE

To investigate the effect of two weeks of repetitive transcranial magnetic stimulation (rTMS) on the attention network in Parkinson's disease (PD) patients.

MATERIALS AND METHODS

Sixty PD patients were randomly divided into equal-sized active- and sham-rTMS groups. Executive function was assessed by neuropsychological tests including the Trail-Making Test (TMT), word fluency test, digit span, Wisconsin Card Sorting Test (WCST) and Stroop test. The attention network was evaluated by the attention network test (ANT). rTMS (5 Hz) was applied over the left dorsolateral prefrontal cortex (DLPFC) in the active-rTMS group, and the sham-rTMS group underwent sham stimulation, both for two weeks. All tests were performed before and after rTMS.

RESULTS

After active rTMS, nonparametric analysis revealed significant improvements in categories completed (CC) (p < 0.001) in the WCST and reaction times (RTs) in part 3 (p = 0.002) and the Stroop interference effect (SIE) (p < 0.001) in the Stroop test. Regarding the ANT, the RTs of the executive control network were significantly reduced (p < 0.001). There was no significant change after sham rTMS.

CONCLUSIONS

In the short term, in PD patients, rTMS improved the executive control network involved in resolving conflicting information. However, it showed milder effects on neuropsychological test outcomes assessing executive function, which may involve different neuromechanisms.Implications for rehabilitationCognitive impairment is common in patients with Parkinson's disease (PD), and it is related to functional disability and reduced quality of life.Attention is a main component of the cognitive system, and attention deficits are responsible for disability.This study demonstrates that rTMS is beneficial for cognitive rehabilitation in PD, as patients showed improved performance on the attention network test and neuropsychological tests.

Prediction of Cognitive Degeneration in Parkinson's Disease Patients Using a Machine Learning Method

This study developed a predictive model for cognitive degeneration in patients with Parkinson's disease (PD) using a machine learning method. The clinical data, plasma biomarkers, and neuropsychological test results of patients with PD were collected and utilized as model predictors. Machine learning methods comprising support vector machines (SVMs) and principal component analysis (PCA) were applied to obtain a cognitive classification model. Using 32 comprehensive predictive parameters, the PCA-SVM classifier reached 92.3% accuracy and 0.929 area under the receiver operating characteristic curve (AUC). Furthermore, the accuracy could be increased to 100% and the AUC to 1.0 in a PCA-SVM model using only 13 carefully chosen features.

Effects of Cycling Dual-Task on Cognitive and Physical Function in Parkinson’s Disease: A Randomized Double-Blind Pilot Study

(1) Background: Those with Parkinson’s disease (PD) may present difficulties in performing dual tasks (DT). The use of DT during training can improve different abilities. Therefore, the objective of this study is to verify the influence of a cycling exercise program combined with a cognitive task on cognitive and physical PD aspects; (2) Methods: A double-blind, randomized pilot study was undertaken. Participants performed a DT intervention composed of cycling and a cognitive task. The cycling parameters, MDS-UPDRS, PDQ-39, TUG Test, 30 s Chair Sit to Stand test and Stroop were used to measure outcomes; (3) Results: DT generated impairment in performing the cycling task, with significant differences in cycling parameters, active and passive distance (m), total work (W) and active speed (rpm). At the cognitive level, there was a trend of improvement in the group that performed the training with DT, which improved by 211%; (4) Conclusions: Combining cycling with a cognitive task caused impairment in the performance of the physical task and an improvement at the cognitive level. Therefore, combining cycling with a cognitive task in a presumably safer environment for patients with PD can be a good way to train these patients for the dual-task challenges with practical applications.

Optimization of cognitive assessment in Parkinsonisms by applying artificial intelligence to a comprehensive screening test

The assessment of cognitive deficits is pivotal for diagnosis and management in patients with parkinsonisms. Low levels of correspondence are observed between evaluations assessed with screening cognitive tests in comparison with those assessed with in-depth neuropsychological batteries. A new tool, we named CoMDA (Cognition in Movement Disorders Assessment), was composed by merging Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Frontal Assessment Battery (FAB). In total, 500 patients (400 with Parkinson’s disease, 41 with vascular parkinsonism, 31 with progressive supranuclear palsy, and 28 with multiple system atrophy) underwent CoMDA (level 1–L1) and in-depth neuropsychological battery (level 2–L2). Machine learning was developed to classify the CoMDA score and obtain an accurate prediction of the cognitive profile along three different classes: normal cognition (NC), mild cognitive impairment (MCI), and impaired cognition (IC). The classification accuracy of CoMDA, assessed by ROC analysis, was compared with MMSE, MoCA, and FAB. The area under the curve (AUC) of CoMDA was significantly higher than that of MMSE, MoCA and FAB (p < 0.0001, p = 0.028 and p = 0.0007, respectively). Among 15 different algorithmic methods, the Quadratic Discriminant Analysis algorithm (CoMDA-ML) showed higher overall-metrics performance levels in predictive performance. Considering L2 as a 3-level continuous feature, CoMDA-ML produces accurate and generalizable classifications: micro-average ROC curve, AUC = 0.81; and AUC = 0.85 for NC, 0.67 for MCI, and 0.83 for IC. CoMDA and COMDA-ML are reliable and time-sparing tools, accurate in classifying cognitive profile in parkinsonisms.

This study has been registered on ClinicalTrials.gov (NCT04858893).

Reduction in Volume of Nucleus Basalis of Meynert Is Specific to Parkinson’s Disease and Progressive Supranuclear Palsy but Not to Multiple System Atrophy

Objectives

To study in vivo gray matter (GM) volumes of the nucleus basalis of Meynert (nbM) in different parkinsonian syndromes and assess their relationship with clinical variables.

Methods

T1-weighted magnetic resonance images from patients with progressive supranuclear palsy (PSP, N = 43), multiple system atrophy (MSA, N = 23), Parkinson’s disease (PD, N = 26), and healthy controls (HC, N = 29) were included. T1-weighted images were analyzed using a voxel-based morphometry approach implemented in the VBM8 toolbox, and nbM volumes were extracted from the spatially normalized GM images using a cyto-architectonically-defined nbM mask in stereotactic standard space. NbM volumes were compared between groups, while controlling for intracranial volume. Further, within each group correlation analyses between nbM volumes and the Mini Mental Status Examination (MMSE), Hoehn and Yahr stage, PSP Rating Scale, Unified Parkinson’s Disease Rating Scale part III and Frontal Assessment Battery scores were performed.

Results

Significantly lower nbM volumes in patients with PSP and PD compared to HC or patients with MSA were found. No significant correlations between MMSE and nbM volumes were detected in any of the subgroups. No significant correlations were found between clinical scores and nbM volumes in PSP or other groups.

Conclusion

nbM volumes were reduced both in PD and PSP but not in MSA. The lack of significant correlations between nbM and cognitive measures suggests that other factors, such as frontal atrophy, may play a more important role than subcortical cholinergic atrophy in PSP patients. These results may indicate that other drug-targets are needed to improve cognitive function in PSP patients.

An Item Response Theory Analysis of the Wisconsin Card Sorting Test in Normal Aging, Alzheimer's Disease and Parkinson's Disease: Neurophysiological Approach

The Wisconsin Card Sorting Test (WCST) is widely used to assess executive function, specifically mental flexibility. Item Response Theory (IRT) has several advantages over classical test theory, including the invariance of the measure. This study aimed to apply IRT to study the psychometric properties of WCST in control subjects and patients with idiopathic Parkinson's disease (PD) and Alzheimer's disease (AD). The sample consisted of 86 controls, 77 Parkinson's disease subjects, and 155 AD subjects. The Rasch model was applied to binary data from the conversion to percentiles adjusted for age and schooling. The R program was used to calibrate the difficulty parameter. The characteristic curves of the items and the estimation of the difficulty parameter for each diagnostic group were obtained. WCST makes it possible to separate between different skill levels among the three diagnostic entities and its application may be useful for other neuropsychological tests. In conclusion, WCST has good clinical sensitivity and excellent discriminant validity in the groups under study, making it possible to separate them between different levels of ability or latent trait. Its application may be useful for other neuropsychological tests.

Do Impulse Control Disorders Impair Car Driving Performance in Patients with Parkinson's Disease?

BACKGROUND

Based on data regarding the prevalence of Parkinson's disease (PD), the prevalence of impulsive control disorders (ICD) in PD, and the percentage of PD patients driving a car, it has to be assumed that at least 50,000 PD patients with ICD in Germany actively drive a car. However, these patients might be at risk for unsafe driving due to ICD-related dysfunctions such as failure to resist an impulse or temptation, to control an act or other altered neurobehavioral processes.

OBJECTIVE

This study determines the influence of ICD on driving ability in PD.

METHODS

We prospectively compared driving simulator performance of 23 PD patients with and 23 matched patients without ICD. ICD had to be socially compensated and presence was defined clinically for primary and questionnaire-based (QUIP-RS) for post-hoc analyses. Furthermore, between-group comparisons of driving-relevant neuropsychological tests were executed.

RESULTS

Except from a lower blinking frequency when changing lanes, overall driving safety of patients with ICD did not differ significantly from those without-regardless of the clinical or QUIP-RS-based ICD definition. ICD severity did not correlate with driving performance, but the latter correlated significantly with mean reaction times and certain neuropsychiatric tests (MoCA, TMT-A, TAP-M "flexibility" and DBQ "error").

CONCLUSION

Clinically compensated ICD does not seem to impair driving safety in PD patients. Rather, cognitive and attentional deficits appear to be clinical markers for driving uncertainty.

Can Task Specificity Impact tDCS-Linked to Dual Task Training Gains in Parkinson's Disease? A Protocol for a Randomized Controlled Trial

Patients with Parkinson's disease (PD) have difficulties while performing dual-task activities, a condition present in everyday life. It is possible that strategies such as transcranial Direct Current Stimulation (tDCS) can be associated with motor training enriched with dual-task training to improve the performance of two concurrent tasks. Currently, it is unclear whether specific tasks and clinical conditions of PD patients have different results after the intervention. Therefore, the proposed randomized controlled trial will examine task-dependency in enhancing the effects of tDCS-linked rehabilitation training on PD and the relationships between baseline outcomes in responders and non-responders to therapy. Fifty-six patients with Parkinson's disease will be recruited to participate in this controlled, double-blind randomized multicentric clinical trial. Patients in modified Hoehn & Yahr stage 1.5-3, age between 40 and 70 years will be included. Subjects will be randomly assigned to an experimental group (EG) and a control group (CG). The EG will perform treadmill gait training associated with dual task exercises+tDCS, while the CG will only engage in treadmill gait training+tDCS. Blinded testers will assess patients before and after 12 intervention sessions and after a 4-week follow-up period. All patients will undergo a screening and an initial visit before being assessed for primary and secondary outcomes. The primary outcome measure is functional mobility measured by Timed Up and Go Test. Secondary outcomes include cognitive function, participation, motor function and body function and structure. This study will evaluate the effectiveness of an intervention protocol with tDCS, dual-task training and gait training in patients with PD. The study will also highlight the clinical factors and variability between individuals that could interfere in the training of a specific task and influence the therapeutic effect. Clinical Trial registration: www.ClinicalTrials.gov, identifier NCT04581590.

Differences in Frontal Lobe Dysfunction in Patients with Episodic and Chronic Migraine

Neuroimaging and neuropsychological investigations have indicated that migraineurs exhibit frontal lobe-related cognitive impairment. We investigated whether orbitofrontal and dorsolateral functioning differed between individuals with episodic migraine (EM) and chronic migraine (CM), focusing on orbitofrontal dysfunction because it is implicated in migraine chronification and medication overuse headache (MOH) in migraineurs. This cross-sectional study recruited women with CM with/without MOH (CM + MOH, CM − MOH), EM, and control participants who were matched in terms of age and education. We conducted neuropsychological assessments of frontal lobe function via the Trail Making Test (TMT) A and B, the Wisconsin Card Sorting Test (WCST), and the Iowa Gambling Task (IGT). We enrolled 36 CM (19 CM + MOH, 17 CM − MOH), 30 EM, and 30 control participants. The CM patients performed significantly (p < 0.01) worse on the TMT A and B than the EM patients and the control participants. The WCST also revealed significant differences, with poorer performance in the CM patients versus the EM patients and the control participants. However, the net scores on the IGT did not significantly differ among the three groups. Our findings suggest that the CM patients exhibited frontal lobe dysfunction, and, particularly, dorsolateral dysfunction. However, we found no differences in frontal lobe function according to the presence or absence of MOH.

A Comprehensive Meta-analysis on Short-term and Working Memory Dysfunction in Parkinson's Disease

A previous meta-analysis demonstrated short-term memory (STM) and working memory (WM) dysfunction in patients with Parkinson's disease (PD). However, considerable research on the topic that calls into question the extent of such impairments in PD has since been published. The aim of the present quantitative review was to provide the largest statistical overview on STM and WM dysfunction in Parkinson's disease (PD), while simultaneously providing novel insights on moderating factors of effect size heterogeneity in PD. The systematic literature search in PubMed, PsycINFO, PsycArticles, Scopus and Web of Science databases allowed us to estimate 350 effect sizes from 145 empirical studies that reported STM and WM scores for patients with PD against healthy controls. The outcomes indicated general dysfunction in the visuospatial domain and poor verbal WM in PD. Subgroup analyses suggested that mild cognitive impairment is associated with STM and WM difficulties in PD. Furthermore, meta-regression analyses revealed that disease duration accounted for more than 80% of the visuospatial STM effect size variance (β = 0.136, p < .001, R² = .8272), larger daily levodopa equivalent dose was associated with WM dysfunction (verbal: β = -0.001, p = .016, R² = .1812; visuospatial: β = 0.003, p = .069, R² = .2340), and years of education partially explained the verbal STM effect size variance (β = -0.027, p = .040, R² = .1171). Collectively, these findings advance our understanding of underlying factors that influence STM and WM functioning in PD, while at the same time providing novel directions for future research.

The Reliability of the Wisconsin Card Sorting Test in Clinical Practice

The Wisconsin Card Sorting Test (WCST) represents the gold standard for the neuropsychological assessment of executive function. However, very little is known about its reliability. In the current study, 146 neurological inpatients received the Modified WCST (M-WCST). Four basic measures (number of correct sorts, categories, perseverative errors, set-loss errors) and their composites were evaluated for split-half reliability. The reliability estimates of the number of correct sorts, categories, and perseverative errors fell into the desirable range (rel ≥ .90). The study therefore disclosed sufficiently reliable M-WCST measures, fostering the application of this eminent psychological test to neuropsychological assessment. Our data also revealed that the M-WCST possesses substantially better psychometric properties than would be expected from previous studies of WCST test-retest reliabilities obtained from non-patient samples. Our study of split-half reliabilities from discretionary construed and from randomly built M-WCST splits exemplifies a novel approach to the psychometric foundation of neuropsychology.

Toward a Computational Neuropsychology of Cognitive Flexibility

Cognitive inflexibility is a well-documented, yet non-specific corollary of many neurological diseases. Computational modeling of covert cognitive processes supporting cognitive flexibility may provide progress toward nosologically specific aspects of cognitive inflexibility. We review computational models of the Wisconsin Card Sorting Test (WCST), which represents a gold standard for the clinical assessment of cognitive flexibility. A parallel reinforcement-learning (RL) model provides the best conceptualization of individual trial-by-trial WCST responses among all models considered. Clinical applications of the parallel RL model suggest that patients with Parkinson's disease (PD) and patients with amyotrophic lateral sclerosis (ALS) share a non-specific covert cognitive symptom: bradyphrenia. Impaired stimulus-response learning appears to occur specifically in patients with PD, whereas haphazard responding seems to occur specifically in patients with ALS. Computational modeling hence possesses the potential to reveal nosologically specific profiles of covert cognitive symptoms, which remain undetectable by traditionally applied behavioral methods. The present review exemplifies how computational neuropsychology may advance the assessment of cognitive flexibility. We discuss implications for neuropsychological assessment and directions for future research.

Repetitive transcranial magnetic stimulation (rTMS) fails to improve cognition in patients with parkinson's disease: a Meta-analysis of randomized controlled trials

BACKGROUND

Cognitive decline is one of the greatest concerns for patients with Parkinson's disease (PD) and their care partners. Repetitive transcranial magnetic stimulation (rTMS) is a nonpharmacological treatment option used to improve cognitive function in PD, but its efficacy is unclear. We performed a meta-analysis to determine whether rTMS improves cognition in PD patients.

METHODS

Eligibility criteria (PICOS) were as follows: (1) 'P': The patients participating were diagnosed with idiopathic PD; (2) 'I': Intervention using rTMS; (3) 'C': Sham stimulation as control; (4) 'O': The outcome of the study included cognitive evaluations; (5) 'S': The study adopted randomized controlled design. The standardized mean difference (SMD) of change of score was applied to measure efficacy, and we used Version 2 of the Cochrane tool to assess risk of bias.

RESULTS

Twelve studies met the inclusion criteria. Compared with sham-controlled group, the pooled result showed a non-significant short-term effect of rTMS on global cognition (SMD: -0.15, 95% CI: -0.59 to 0.29, I² = 36.7%), executive function (SMD: 0.03, 95% CI: -0.21 to 0.26, I² = 0.0%), and attention and working memory (SMD: 0.05, 95% CI: -0.25 to 0.35, I² = 0.0%). Long-term outcomes were either shown to be statistically nonsignificant.

CONCLUSIONS

Based on a limited number of studies, rTMS fails to improve cognition in PD. We call for additional high-quality randomized controlled trials with adequate sample sizes to determine the efficacy of rTMS.

Chronic versus recent expressive suppression burdens are differentially associated with cognitive performance among older adults

Introduction: Expressive suppression (ES; suppression of affective behavior) has been shown to have a deleterious impact on subsequently administered tests of executive functions (EF), threatening validity, and reliability of EF assessment. Past research has shown that recent ES (i.e., across 24 hours prior to testing) and chronic ES (i.e., across 2 weeks prior to testing) have differential impact on test performance. The present study compared the association of chronic vs. recent ES with speed vs. accuracy of performance on tests of EF and tests of lower-order processes.

METHOD

Participants were 255 community-dwelling older adults aged 60 and older. Participants completed timed subtests of the Delis-Kaplan Executive Function System and the Burden of State Emotion Regulation Questionnaire.

RESULTS

Hierarchical linear regressions examined the contributions of chronic vs. recent ES to test performance. Recent ES was related to scores of both speed and accuracy on EF tests. The association between recent ES and EF errors held beyond covariates (i.e., chronic ES, demographics, depression, and general cognitive status). In contrast, the association between recent ES and EF speed was fully explained by EF error scores. Chronic ES was associated only with speed of performance and only on lower-order tasks, but this relationship did not survive correction for cognitive, psychiatric, and demographic factors.

CONCLUSIONS

Recent ES appears to be a risk factor for EF lapses. Chronic ES, while related to performance speed, seems to also relate to several other cognitive, psychiatric, and demographic factors, which themselves explain slower information processing.

Parallel model-based and model-free reinforcement learning for card sorting performance

The Wisconsin Card Sorting Test (WCST) is considered a gold standard for the assessment of cognitive flexibility. On the WCST, repeating a sorting category following negative feedback is typically treated as indicating reduced cognitive flexibility. Therefore such responses are referred to as 'perseveration' errors. Recent research suggests that the propensity for perseveration errors is modulated by response demands: They occur less frequently when their commitment repeats the previously executed response. Here, we propose parallel reinforcement-learning models of card sorting performance, which assume that card sorting performance can be conceptualized as resulting from model-free reinforcement learning at the level of responses that occurs in parallel with model-based reinforcement learning at the categorical level. We compared parallel reinforcement-learning models with purely model-based reinforcement learning, and with the state-of-the-art attentional-updating model. We analyzed data from 375 participants who completed a computerized WCST. Parallel reinforcement-learning models showed best predictive accuracies for the majority of participants. Only parallel reinforcement-learning models accounted for the modulation of perseveration propensity by response demands. In conclusion, parallel reinforcement-learning models provide a new theoretical perspective on card sorting and it offers a suitable framework for discerning individual differences in latent processes that subserve behavioral flexibility.

A Computational Study of Executive Dysfunction in Amyotrophic Lateral Sclerosis

Executive dysfunction is a well-documented, yet nonspecific corollary of various neurological diseases and psychiatric disorders. Here, we applied computational modeling of latent cognition for executive control in amyotrophic lateral sclerosis (ALS) patients. We utilized a parallel reinforcement learning model of trial-by-trial Wisconsin Card Sorting Test (WCST) behavior. Eighteen ALS patients and 21 matched healthy control participants were assessed on a computerized variant of the WCST (cWCST). ALS patients showed latent cognitive symptoms, which can be characterized as bradyphrenia and haphazard responding. A comparison with results from a recent computational Parkinson's disease (PD) study (Steinke et al., 2020, J Clin Med) suggests that bradyphrenia represents a disease-nonspecific latent cognitive symptom of ALS and PD patients alike. Haphazard responding seems to be a disease-specific latent cognitive symptom of ALS, whereas impaired stimulus-response learning seems to be a disease-specific latent cognitive symptom of PD. These data were obtained from the careful modeling of trial-by-trial behavior on the cWCST, and they suggest that computational cognitive neuropsychology provides nosologically specific indicators of latent facets of executive dysfunction in ALS (and PD) patients, which remain undiscoverable for traditional behavioral cognitive neuropsychology. We discuss implications for neuropsychological assessment, and we discuss opportunities for confirmatory computational brain imaging studies.

Computational Modeling for Neuropsychological Assessment of Bradyphrenia in Parkinson's Disease

The neural mechanisms of cognitive dysfunctions in neurological diseases remain poorly understood. Here, we conjecture that this unsatisfying state-of-the-art is in part due to the non-specificity of the typical behavioral indicators for cognitive dysfunctions. Our study addresses the topic by advancing the assessment of cognitive dysfunctions through computational modeling. We investigate bradyphrenia in Parkinson's disease (PD) as an exemplary case of cognitive dysfunctions in neurological diseases. Our computational model conceptualizes trial-by-trial behavioral data as resulting from parallel cognitive and sensorimotor reinforcement learning. We assessed PD patients 'on' and 'off' their dopaminergic medication and matched healthy control (HC) participants on a computerized version of the Wisconsin Card Sorting Test. PD patients showed increased retention of learned cognitive information and decreased retention of learned sensorimotor information from previous trials in comparison to HC participants. Systemic dopamine replacement therapy did not remedy these cognitive dysfunctions in PD patients but incurred non-desirable side effects such as decreasing cognitive learning from positive feedback. Our results reveal novel insights into facets of bradyphrenia that are indiscernible by observable behavioral indicators of cognitive dysfunctions. We discuss how computational modeling may contribute to the advancement of future research on brain-behavior relationships and neuropsychological assessment.

Association of Motor and Cognitive Symptoms with Health-Related Quality of Life and Caregiver Burden in a German Cohort of Advanced Parkinson's Disease Patients

Parkinson's disease (PD) is a chronic progressive movement disorder with severe reduction in patients' health-related quality of life (HR-QoL). Motor and cognitive symptoms are especially linked with decreased PD patients' HR-QoL. However, the relationship of these symptoms to caregiver burden is relatively unclear. Influence of the Montreal Cognitive Assessment scale (MoCA) as a cognitive screening tool and Movement Disorders Society Unified Parkinson's disease Rating Scale MDS-UPDRS symptoms in relation to patients' HR-QoL and caregivers` burden was analyzed. PD patients (n = 124) completed MDS-UPDRS, MoCA, and the PD questionnaire 8 (PDQ-8) as a measure of quality of life. Caregivers (n = 78) were assessed by the PD caregiver burden inventory (PDCB). PDQ-8 and PDCB scores were regressed on MDS-UPDRS subscales and MoCA subscores. PDQ-8 correlated with attention (R² 0.1282; p < 0.001) and executive (R² 0.0882; p 0.001) MoCA subscores and all parts of the MDS-UPDRS. PDCB correlated most strongly with MDS-UPDRS part III motor symptoms (R² 0.2070; p < 0.001) and the MoCA attention subscore (R² 0.1815; p < 0.001). While all facets of PD symptoms assessed by the MDS-UPDRS relate to PD patients' quality of life, motor symptoms are the most relevant factor for the prediction of caregiver burden. In addition, patients' attentional symptoms seem to affect not only them, but also their caregivers. These findings show the potential of a detailed analysis of MDS-UPDRS and MoCA performance in PD patients.

Can the Executive Control Network be Used to Diagnose Parkinson's Disease and as an Efficacy Indicator of Deep Brain Stimulation?

Objective

The aim of this work was to investigate whether there are differences in the executive control network (ECN) between patients with Parkinson's disease (PD) before and after deep brain stimulation (DBS) surgery and to explore how deep brain stimulation (DBS) surgery affects ECN connectivity in patients with PD.

Methods

Resting-state magnetic resonance imaging (MRI) data were obtained from 23 patients with Parkinson's disease preoperatively (pre-PD) and postoperatively (post-PD) and 14 normal controls (CN). The right dorsolateral prefrontal cortex (DLPFC) was used as the seed region of interest (ROI) to study the characteristics of the functional connectivity of the ECN in these subjects.

Results

There were differences in the ECN among PD patients before and after surgery and between the CN. Compared with the CN group, the pre-PD patients showed significantly reduced functional connectivity (FC) between the DLPFC and the left inferior frontal gyrus, left precuneus, left cerebellum posterior lobe, right middle frontal gyrus, right inferior parietal gyrus, right posterior central gyrus, right precuneus, and right inferior frontal gyrus. Compared to the CN group, the post-PD patients showed significantly reduced FC between the DLPFC and left inferior frontal gyrus, left precuneus, left cerebellum posterior lobe, right middle frontal gyrus, right inferior frontal gyrus, and right parietal lobule. There is no difference in the ECN between the pre-PD patients and the post-PD patients.

Conclusions

The FC of ECN in PD patients was different from that in normal controls, but the FC of the ECN in patients with PD may not be altered by DBS. This suggests that the ECN may be considered an imaging biomarker for the identification of PD but may not be a good imaging biomarker for the evaluation of DBS efficacy.

Risky decision making and cognitive flexibility among online sports bettors in Nigeria

Online sports betting is a popular recreational activity in Nigeria. Like other forms of gambling, risk of pathological progression exists for gamblers who continue betting despite severe financial and psychosocial consequences. In the present study, we examined whether this population of gamblers shows deficits in decision making and cognitive flexibility that have been documented in Western gambling populations. Thirty‐six online sports bettors and 42 non‐gambling participants completed a version of the Iowa gambling task (IGT) and an established set‐shifting task for the assessment of cognitive flexibility. The two groups did not differ significantly in the selection of disadvantageous decks on the IGT. In contrast, sports bettors committed significantly more errors on the set‐shifting task than non‐gambling control participants. As this performance deficit was not specific to trials requiring a set shift, it most likely resulted from gambling‐related changes in general cognitive or motivational abilities that are required to successfully complete challenging mental tasks. While our results illustrate that findings from Western populations cannot automatically be generalised to other contexts, it should be noted that we focused on only one particular type of gambling and included mostly participants with mild gambling‐related problems.

Are Difficult-To-Study Populations too Difficult to Study in a Reliable Way?

Abstract. Replication studies, pre-registration, and increases in statistical power will likely improve the reliability of scientific evidence. However, these measures face critical limitations in populations that are inherently difficult to study. Members of difficult-to-study populations (e.g., patients, children, non-human animals) are less accessible to researchers, which typically results in small-sample studies that are infeasible to replicate. Nevertheless, meta-analyses on clinical neuropsychological data suggest that difficult-to-study populations can be studied in a reliable way. These analyses often produce unbiased effect-size estimates despite aggregating across severely underpowered original studies. This finding can be attributed to a neuropsychological research culture involving the non-selective reporting of results from standardized and validated test procedures. Consensus guidelines, test manuals, and psychometric evidence constrain the methodological choices made by neuropsychologists, who regularly report the results from neuropsychological test batteries irrespective of their statistical significance or novelty. Comparable shifts toward more standardization and validation, complete result reports, and between-lab collaborations can allow for a meaningful and reliable study of psychological phenomena in other difficult-to-study populations.

A Meta-Analysis of Relationships between Measures of Wisconsin Card Sorting and Intelligence

The Wisconsin Card Sorting Test (WCST) represents a widely utilized neuropsychological assessment technique for executive function. This meta-analysis examined the discriminant validity of the WCST for the assessment of mental shifting, considered as an essential subcomponent of executive functioning, against traditional psychometric intelligence tests. A systematic search was conducted, resulting in 72 neuropsychological samples for the meta-analysis of relationships between WCST scores and a variety of intelligence quotient (IQ) domains. The study revealed low to medium-sized correlations with IQ domains across all WCST scores that could be investigated. Verbal/crystallized IQ and performance/fluid IQ were indistinguishably associated with WCST scores. To conclude, the WCST assesses cognitive functions that might be partially separable from common conceptualizations of intelligence. More vigorous initiatives to validate putative indicators of executive function against intelligence are required.

Age, education and gender effects on Wisconsin card sorting test: standardization, reliability and validity in healthy Argentinian adults

The Wisconsin Card Sorting Test (WCST) is a widely used neuropsychological assessment of executive functioning. The aim of this study was to provide norm values and analyze the psychometric properties of WCST in healthy Argentinian adults aged from 18 to 89 years old (N = 235). Descriptive statistics are reported as means, standard deviations and percentiles, with the effects of age, education and gender being investigated by ANOVA, and with the effect sizes being calculated. The psychometrics were studied using the WCST structure, reliability, convergent validity, and discriminant validity, and WCST norms adjusted for age and educational level are proposed. This instrument is a reliable and valid tool for the assessment of executive functions. However, as the age- and educational-related effects were demonstrated, these characteristics need to be considered before interpreting WCST scores. Regarding gender, no differences were found. Our results expand the geographical and sociocultural applicability of WCST.

Early detection of cognitive impairment in Parkinson's disease with the use of the Wisconsin Card Sorting Test: correlations with Montreal Cognitive Assessment and smell identification test

Cognitive function is often impaired in early Parkinson's disease (PD). The Wisconsin Card Sorting Test (WCST) is a neuropsychological test of "set-shifting" ability. To see whether WCST is useful for detecting early changes of cognitive function in PD, we examined the correlations of WCST with the Montreal Cognitive Assessment (MoCA) and the Odor Stick Identification Test (OSIT). Subjects were 48 PD patients (age 66 ± 10 years; Hoehn & Yahr stage 2.3 ± 0.8; mean duration 3.1 ± 2.5 years). WCST sub-scores for categories achieved (CA), perseverative errors of Nelson type (PEN), and difficulties of maintaining set (DMS) were evaluated. MoCA-J (Japanese version) and OSIT-J (Japanese version) were done in that order, followed by the WCST. In PD patients, CA was 2.2 ± 2.0, PEN was 7.0 ± 6.4, and DMS was 2.3 ± 2.0, and all were worse than those of age-matched normal subjects. MoCA-J scores significantly correlated with PEN. OSIT-J scores were also significantly correlated with CA and DMS. As MoCA-J and OSIT-J show high sensitivity and specificity for detecting mild cognitive impairment in PD, WCST may also be a useful supplementary diagnostic tool for early and mild cognitive impairment in PD patients.

Multiple Levels of Control Processes for Wisconsin Card Sorts: An Observational Study

We explored short-term behavioral plasticity on the Modified Wisconsin Card Sorting Test (M-WCST) by deriving novel error metrics by stratifying traditional set loss and perseverative errors. Separating the rule set and the response set allowed for the measurement of performance across four trial types, crossing rule set (i.e., maintain vs. switch) and response demand (i.e., repeat vs. alternate). Critically, these four trial types can be grouped based on trial-wise feedback on t − 1 trials. Rewarded (correct) maintain t − 1 trials should lead to error enhancement when the response demands shift from repeat to alternate. In contrast, punished (incorrect) t − 1 trials should lead to error suppression when the response demands shift from repeat to alternate. The results supported the error suppression prediction: An error suppression effect (ESE) was observed across numerous patient samples. Exploratory analyses show that the ESE did not share substantial portions of variance with traditional neuropsychological measures of executive functioning. They further point into the direction that striatal or limbic circuit neuropathology may be associated with enhanced ESE. These data suggest that punishment of the recently executed response induces behavioral avoidance, which is detectable as the ESE on the WCST. The assessment of the ESE might provide an index of response-related avoidance learning on the WCST.

CogBeacon: A Multi-Modal Dataset and Data-Collection Platform for Modeling Cognitive Fatigue

In this work, we present CogBeacon, a multi-modal dataset designed to target the effects of cognitive fatigue in human performance. The dataset consists of 76 sessions collected from 19 male and female users performing different versions of a cognitive task inspired by the principles of the Wisconsin Card Sorting Test (WCST), a popular cognitive test in experimental and clinical psychology designed to assess cognitive flexibility, reasoning, and specific aspects of cognitive functioning. During each session, we record and fully annotate user EEG functionality, facial keypoints, real-time self-reports on cognitive fatigue, as well as detailed information of the performance metrics achieved during the cognitive task (success rate, response time, number of errors, etc.). Along with the dataset we provide free access to the CogBeacon data-collection software to provide a standardized mechanism to the community for collecting and annotating physiological and behavioral data for cognitive fatigue analysis. Our goal is to provide other researchers with the tools to expand or modify the functionalities of the CogBeacon data-collection framework in a hardware-independent way. As a proof of concept we show some preliminary machine learning-based experiments on cognitive fatigue detection using the EEG information and the subjective user reports as ground truth. Our experiments highlight the meaningfulness of the current dataset, and encourage our efforts towards expanding the CogBeacon platform. To our knowledge, this is the first multi-modal dataset specifically designed to assess cognitive fatigue and the only free software available to allow experiment reproducibility for multi-modal cognitive fatigue analysis.

Effects of rule uncertainty on cognitive flexibility in a card-sorting paradigm

Cognitive flexibility has been studied in two separate research traditions. Neuropsychologists typically rely on rather complex assessment tools such as the Wisconsin Card Sorting Test (WCST). In contrast, task-switching paradigms are used in experimental psychology to obtain more specific measures of cognitive flexibility. We aim to contribute to the integration of these research traditions by examining the role of the key factor that differs between the WCST and experimental task-switching paradigms: rule uncertainty. In two experimental studies, we manipulated the degree of rule uncertainty after rule switches in a computerized version of the WCST. Across a variety of task parameters, reducing rule uncertainty consistently impaired the speed and accuracy of responses when the rule designated to be more likely turned out to be incorrect. Other performance measures such as the number of perseverative errors were not significantly affected by rule uncertainty. We conclude that a fine-grained analysis of WCST performance can dissociate behavioural indicators that are affected vs. unaffected by rule uncertainty. By this means, it is possible to integrate WCST results and findings obtained from task-switching paradigms that do not involve rule uncertainty.

Executive functioning: perspectives on neurotrophic activity and pharmacology

Executive functioning is a high-level cognitive ability, regulating other abilities and behaviors to achieve desired goals. A typical executive task can be defined as the capacity to maintain one's attention on the current task, that is, responding only to the correct but not to distractive stimuli. Impairments of executive functions, or executive dysfunctions, have a growing impact on everyday life and academic achievement and are usually an early feature, and one of the core features, in brain injury and memory and behavioral disorders. Furthermore, emerging evidence indicates that memory therapeutics cannot achieve their clinical benefits in cognition if executive dysfunction is not effectively and simultaneously treated. Improvement of executive functions might be achieved through targeting some signaling pathways in the brain, including the brain-derived neurotrophic factor signaling pathways. These agents may be useful either as stand-alone interventions for patients with executive dysfunction and/or psychiatric and memory disorders or as essential adjuncts to drugs that target the underlying pathology in various brain injury and memory and behavioral disorders.