Wisconsin card sorting test as a measure of executive function impairments in stroke patients

Cognitive Inflexibility Predicts Negative Symptoms Severity in Patients with First-Episode Psychosis: A 1-Year Follow-Up Study

Negative symptoms and cognitive deficits play a major role in psychosis and significantly influence the functional outcomes of patients, particularly those with a first episode of psychosis (FEP). However, limited research has explored the predictive capacity of cognitive deficits during FEP for subsequent negative symptomatology. Drawing from the Athens FEP research study, we conducted a retrospective longitudinal study in 80 individuals with FEP. All patients were drug naive at admission. Cognitive tests were administered at 1-month and 1-year post-admission, while negative symptomatology was assessed at the same time points using PANSS by trained raters. We considered confounding factors such as age, gender, duration of untreated psychosis (DUP), treatment received, premorbid social adjustment, and premorbid IQ. Univariate regression analysis identified cognitive domains that correlated with negative symptomatology. These, along with the confounders, were incorporated into a multiple regression, with the 1-year PANSS negative scale serving as the dependent variable. Employing the backward elimination technique, we found a statistically significant inverse relationship between the categories completed in the Wisconsin card sorting test (WCST) and the 1-year PANNS negative scale (p = 0.01), beyond the associations with DUP and the 1-month PANSS negative scale. Our results suggest that cognitive flexibility, a key component of executive functions, predicts negative symptom severity one year after FEP.

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.

A Verbal Card Sorting Task to Measure Executive Functions

PURPOSE

The Wisconsin Card Sorting Test (WCST) is commonly used to measure nonverbal executive functions (EFs) in a variety of clinical populations. However, in some clinical populations (e.g., people with aphasia), deficits may be present in more linguistic (or verbal) domains and less pronounced in nonverbal domains. Thus, when determining possible deficits in these individuals, it is critical to assess both verbal and nonverbal cognitive abilities. The purpose of this study was to create a verbal card sorting task (VCST) to complement the WCST.

METHOD

We created the VCST by modifying a computerized version of the WCST, the Berg Card Sorting Task (BCST). We then compared 35 individuals with mild traumatic brain injury (mTBI) and 33 matched controls' performance on each task. We tested the VCST in individuals with mTBI first because they demonstrate impaired EFs but unimpaired language. We therefore expected the mTBI group to perform similarly on the VCST and BCST, suggesting that the two tasks measure EFs similarly.

RESULTS

In line with our hypothesis, the mTBI group had unimpaired inhibition and sustained attention but impaired shifting on each task. Component loadings for both tasks were also similar, and participants' inhibition and shifting scores positively correlated across the two tasks.

CONCLUSIONS

Together, these findings suggest that the VCST is a potentially useful tool for measuring verbal EF deficits. Our results also provide important insights into the EF impairments experienced by individuals with mTBI.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23230475.

Cognitive impairment and factors influencing depression in adolescents with suicidal and self-injury behaviors: a cross-sectional study

BACKGROUND

Non-suicidal self-injury (NSSI) and suicide attempts (SAs) by adolescent patients with depression have become serious public health problems. There is still insufficient research evidence on the effects of NSSI and SAs on neurocognitive functioning in adolescents. Cognitive function alterations may be associated with SAs and self-injury. NSSI and SAs have different influencing factors.

METHODS

Participants were recruited from outpatient clinics and included 142 adolescent patients with depression (12-18 years old). This cohort included the SAs group (n = 52), NSSI group (n = 65), and depression without SAs/NSSI control group (n = 25). All participants underwent a clinical interview and neuropsychological assessment for group comparisons, and post-hoc tests were performed. Finally, partial correlation analysis was used to explore factors related to changes in cognitive function.

RESULTS

The SAs group performed significantly worse than the control group in executive function and working memory. The depression score was directly proportional to the executive function of the SAs group, whereas cognitive functioning in the NSSI group was associated with borderline traits and rumination.

CONCLUSIONS

These findings suggest that impairment of executive function and working memory may be a common pattern in adolescent depressed patients with SAs. However, borderline traits and rumination may be indicative of NSSI but not SAs.

Logical memory, visual reproduction, and verbal paired associates are effective embedded validity indicators in patients with traumatic brain injury

OBJECTIVE

This study was design to evaluate the potential of the recognition trials for the Logical Memory (LM), Visual Reproduction (VR), and Verbal Paired Associates (VPA) subtests of the Wechsler Memory Scales-Fourth Edition (WMS-IV) to serve as embedded performance validity tests (PVTs).

METHOD

The classification accuracy of the three WMS-IV subtests was computed against three different criterion PVTs in a sample of 103 adults with traumatic brain injury (TBI).

RESULTS

The optimal cutoffs (LM ≤ 20, VR ≤ 3, VPA ≤ 36) produced good combinations of sensitivity (.33-.87) and specificity (.92-.98). An age-corrected scaled score of ≤5 on either of the free recall trials on the VPA was specific (.91-.92) and relatively sensitive (.48-.57) to psychometrically defined invalid performance. A VR I ≤ 5 or VR II ≤ 4 had comparable specificity, but lower sensitivity (.25-.42). There was no difference in failure rate as a function of TBI severity.

CONCLUSIONS

In addition to LM, VR, and VPA can also function as embedded PVTs. Failing validity cutoffs on these subtests signals an increased risk of non-credible presentation and is robust to genuine neurocognitive impairment. However, they should not be used in isolation to determine the validity of an overall neurocognitive profile.

The impact of subcortical stroke-related aphasia on executive functions and working memory

Aphasia is a common post-stroke disorder characterized by impairments in speaking, listening, reading, and writing. Although cognitive impairments have been well studied in cortical aphasia, deficits associated with subcortical aphasia remain to be elucidated. The current study aimed to assess executive functions (EF) and working memory (WM) in patients with subcortical aphasia, and investigate the relationship between language abilities and cognition deficits. Participants of this research included patients with thalamus lesions (n = 9; mean age = 53.89 years) and healthy individuals (n = 9; mean age = 54.33 years). Assessment materials were the Mini-Mental State Examination (MMSE), Persian Western Aphasia Battery (P-WAB-1), digit span subtest of Adult Wechsler Test (WAIS-R), and Wisconsin Card Sorting Test (WCST). Obtained results revealed significant differences in all components of EF, as well as in WM forward and backward digit spans between patients and healthy individuals. However, investigating the relationship between MMSE and AQ scores and components of EF and WM revealed no significant difference. In conclusion, the findings of the present research indicated defects in cognitive functions, including WM and EF, in patients with subcortical stroke. Accordingly, it is crucial to provide optimal rehabilitation therapies for the improvement of language and cognitive problems upon subcortical aphasia.

Multivariate Models of Performance Validity: The Erdodi Index Captures the Dual Nature of Non-Credible Responding (Continuous and Categorical)

This study was designed to examine the classification accuracy of the Erdodi Index (EI-5), a novel method for aggregating validity indicators that takes into account both the number and extent of performance validity test (PVT) failures. Archival data were collected from a mixed clinical/forensic sample of 452 adults referred for neuropsychological assessment. The classification accuracy of the EI-5 was evaluated against established free-standing PVTs. The EI-5 achieved a good combination of sensitivity (.65) and specificity (.97), correctly classifying 92% of the sample. Its classification accuracy was comparable with that of another free-standing PVT. An indeterminate range between Pass and Fail emerged as a legitimate third outcome of performance validity assessment, indicating that the underlying construct is an inherently continuous variable. Results support the use of the EI model as a practical and psychometrically sound method of aggregating multiple embedded PVTs into a single-number summary of performance validity. Combining free-standing PVTs with the EI-5 resulted in a better separation between credible and non-credible profiles, demonstrating incremental validity. Findings are consistent with recent endorsements of a three-way outcome for PVTs (Pass, Borderline, and Fail).

Motor symptom asymmetry predicts non-motor outcome and quality of life following STN DBS in Parkinson's disease

Risk factors for long-term non-motor symptoms and quality of life following subthalamic nucleus deep brain stimulation (STN DBS) have not yet been fully identified. In the present study, we investigated the impact of motor symptom asymmetry in Parkinson's disease. Data were extracted for 52 patients with Parkinson's disease (half with predominantly left-sided motor symptoms and half with predominantly right-sided ones) who underwent bilateral STN and a matched healthy control group. Performances for cognitive tests, apathy and depression symptoms, as well as quality-of-life questionnaires at 12 months post-DBS were compared with a pre-DBS baseline. Results indicated a deterioration in cognitive performance post-DBS in patients with predominantly left-sided motor symptoms. Performances of patients with predominantly right-sided motor symptoms were maintained, except for a verbal executive task. These differential effects had an impact on patients' quality of life. The results highlight the existence of two distinct cognitive profiles of Parkinson's disease, depending on motor symptom asymmetry. This asymmetry is a potential risk factor for non-motor adverse effects following STN DBS.

Neurocognitive endophenotypes in pediatric OCD probands, their unaffected parents and siblings

BACKGROUND

Limited extant research on neurocognitive endophenotypes in obsessive-compulsive disorder (OCD) show inconsistent results. Limitations of this body of literature include small sample sizes, strict exclusion criteria, lack of objective standard normalized test scores, and significant lack of studies utilizing pediatric probands. This study aimed to address these limitations.

METHODS

A large carefully screened cohort of pediatric OCD (n = 102), their unaffected siblings (n = 78), and parents (n = 164), completed a neuropsychological battery. To compare participants at different ages and developmental stages, standard scores were computed using test norms. Cluster-robust regression with sample size-adjusted sandwich estimates of variance, and interclass correlations were computed. False Discovery Rate procedures were employed to correct for multiplicity.

RESULTS

Probands, siblings and parents demonstrated deficient task performance (Z < -0.5) on the 'number of trials to complete first category' on the Wisconsin Card Sorting Test, and on the Stroop color naming trials. Compared to test norms, the three groups exhibited medium to large effect sizes on these outcome measures. No other meaningful familial trends were found.

CONCLUSIONS

OCD probands, their unaffected siblings and parents exhibited deficiencies in specific subdomains of cognitive flexibility and inhibitory control, namely, initial concept formation and proactive control, which may be valid candidate neurocognitive endophenotypes of OCD. No other meaningful familial effect has been found on other functions, including other executive function indices such as perseverations and interference control. These results highlight the need to carefully examine individual outcomes from executive function tests instead of the tendency to focus largely on major outcome measures.

Five shades of gray: Conceptual and methodological issues around multivariate models of performance validity

OBJECTIVE

This study was designed to empirically investigate the signal detection profile of various multivariate models of performance validity tests (MV-PVTs) and explore several contested assumptions underlying validity assessment in general and MV-PVTs specifically.

METHOD

Archival data were collected from 167 patients (52.4%male; MAge = 39.7) clinicially evaluated subsequent to a TBI. Performance validity was psychometrically defined using two free-standing PVTs and five composite measures, each based on five embedded PVTs.

RESULTS

MV-PVTs had superior classification accuracy compared to univariate cutoffs. The similarity between predictor and criterion PVTs influenced signal detection profiles. False positive rates (FPR) in MV-PVTs can be effectively controlled using more stringent multivariate cutoffs. In addition to Pass and Fail, Borderline is a legitimate third outcome of performance validity assessment. Failing memory-based PVTs was associated with elevated self-reported psychiatric symptoms.

CONCLUSIONS

Concerns about elevated FPR in MV-PVTs are unsubstantiated. In fact, MV-PVTs are psychometrically superior to individual components. Instrumentation artifacts are endemic to PVTs, and represent both a threat and an opportunity during the interpretation of a given neurocognitive profile. There is no such thing as too much information in performance validity assessment. Psychometric issues should be evaluated based on empirical, not theoretical models. As the number/severity of embedded PVT failures accumulates, assessors must consider the possibility of non-credible presentation and its clinical implications to neurorehabilitation.

Eye Movement Technique to Improve Executive Function in Patients With Stroke: A Randomized Controlled Trial

Objective: To investigate the efficacy of eye movement technique for the treatment of executive dysfunction of patients with stroke.

Methods: This was a prospective, single-blinded, randomized, controlled, single-center clinical trial conducted from June 2018 to December 2019 in patients with stroke. The patients were randomized 1:1 to the routine (conventional management) and eye-move group (routine management plus eye movement technique: 5-min goal management training, 5-min computer-aided working memory, and 10 min of inhibitory control training and set conversion training). The intervention lasted 6 weeks, followed by a 4-week follow-up. The primary endpoint was the Behavioral Assessment of the Dysexecutive Syndrome (BADS) score. The secondary endpoints mainly included the Montreal Cognitive Assessment (MoCA), Wisconsin Card Sorting Test (WCST), and modified Barthel Index (MBI) scores.

Results: Sixty-four patients were enrolled (32/group). After the 6-week intervention, the BADS and WCST scores of the eye-move group were significantly improved than those of the routine group (all P < 0.05), but the effects were attenuated in certain subscores after follow-up (all P > 0.05). The MoCA and MBI scores of the eye-move group were significantly higher, and the reaction time was significantly lower than those of the routine group at 4 weeks after the intervention (all P < 0.05). After follow-up, the MBI scores of the eye-move group were still higher than that of the routine group (P < 0.001), but there were no differences for MoCA scores and reaction time (both P > 0.05).

Conclusion: The eye movement technique could improve the executive function of patients with stroke. These results have to be confirmed.

This was a prospective, single-blinded, randomized, controlled, single-center clinical trial (ChiCTR2000036393).

Clinical Trial Registration: [www.chictr.org.cn], identifier [ChiCTR2000036393].

Twin-To-Twin Transfusion Syndrome Donor and Recipient and Their Subsequent Cognitive Functioning in Late Childhood as Juvenile Athletes-A Case Study

Objective: It is estimated that twin-to-twin transfusion syndrome (TTTS) occurs in 10–15% of monochorionic twin pregnancies. One of the fetuses takes on the role of donor and the other of recipient. The treatment administered involves serial amnioreduction and laser photocoagulation of the communicating blood vessels. After TTTS, children may have deficiencies in psychomotor functioning, in particular in cognitive functions, expressive language, and motor skills. Few scientific reports indicate that twins after TTTS do not demonstrate significant differences in tests which measure intellectual functioning. Methods: The cognitive functioning of twins in the late childhood period was compared using the following tools: an analysis of their medical history, an interview with their parents, and neuropsychological tests allowing the evaluation of their whole profile of cognitive functions. Case Study: Cognitive functioning in the late childhood period was analyzed in a pair of 11-year-old male twins (juvenile athletes), a donor and a recipient, who had developed TTTS syndrome in the prenatal period. Results: Comparison of the cognitive functioning profile of the donor and recipient revealed that children with a history of TTTS develop normally in terms of cognitive and motor functioning in late childhood. A comparative analysis of the donor and recipient was more favorable for the recipient, who had a higher level of general intelligence, visual–motor memory, and semantic fluency. Conclusions: The fact that both the donor and the recipient chose to pursue athletics suggests that gross motor skills are their strongest suit. Playing sports as a method of rehabilitation of cognitive function of children born prematurely after TTTS could contribute to the improvement of cognitive functioning.

Atrophic Pattern of Hippocampal Subfields in Post-Stroke Demented Patient

BACKGROUND

Previous studies have demonstrated that hippocampal atrophy is a hallmark of dementia and can be used to predict the outcome of post-stroke demented (PSD) patients. The hippocampus consists of several subfields but their involvement in the pathophysiology of the PSD remains unclear.

OBJECTIVE

The present study aimed to investigate volumetric alterations of hippocampal subfields in patients with PSD.

METHODS

High-resolution T1-weighted images were collected from 27 PSD and 28 post-stroke nondemented (PSND) patients who recovered from ischemic stroke, and 17 age-matched normal control (NC). We estimated the volumes of the hippocampal subfields using FreeSurfer 6.0 which segmented the hippocampus into 12 subfields in each hemisphere. The volumetric differences between the groups were evaluated by the two-sample tests after regressing out the age, sex, education, and total intracranial volume.

RESULTS

Compared with NC group, PSD group showed smaller volumes in the entire hippocampus and its subfields, and such differences were not found in PSND group. Moreover, we found the dementia-specific atrophy in the left granule cell layer of dentate gyrus (GC-DG) and CA4 in the PSD patients compared with NC and PSND. Regression analysis showed positive correlations between the changes of cognitive performance and the asymmetry index in the CA3/4 and GC-DG of the PSD group. Furthermore, we found that the volumes of hippocampal subfields provided a better classification performance than the entire hippocampus.

CONCLUSION

Our findings suggest that the hippocampus is reduced in the PSD patients and it presents a selective subfield involvement.

Impulsiveness, personality traits and executive functioning in patients with juvenile myoclonic epilepsy

PURPOSE

To evaluate impulsiveness in adult patients with JME and its relationship with personality traits and executive functioning.

METHODS

Patients completed psychiatric evaluation (DSM IV), Barratt Impulsiveness Scale (BIS-11), Neo Revised Personality Inventory (NEO PI-R) and executive functioning evaluation comprising Controlled Oral Word Association (COWA), Digit Span, Trail Making Tests (TMT), Stroop Test (ST) and Wisconsin Card Sorting Test (WSCT). Healthy controls (63 % female, mean age 35.7 yrs. (±8.37)) were examined to allow calculation of z-scores.

RESULTS

50 patients (70 % female; mean age 32.5 yrs. (±9.2)) presented higher scores of Total (z=-0.37; p = 0.005) and Motor Impulsiveness (z=-0.79; p < 0.001) on BIS-11. Motor Impulsiveness was associated with higher rates of mild psychiatric disorders (depression and anxiety) (p = 0.035) and worse myoclonic seizure control (p = 0.007). NEO PI-R showed differences on Neuroticism (z=-0.60; p < 0.001), Openness (z = 0.38; p = 0.043), Agreeableness (z=-0.38; p = 0.033) and Conscientiousness (z=-0.53; p = 0.003). There were positive correlations between BIS-11 and Neuroticism with Total, Motor and Non-Planning Impulsiveness, on the other hand, Conscientiousness was negatively correlated with these as well as with Attentive Impulsiveness. Patients performance was worse than that of controls on COWA (z=-0.43; p = 0.009) and WCST's Total Number of Completed Categories (z=-2.08; p = 0.005), Trials Taken to Complete First Category (z=-1.56; p = 0.013), Percentage of Total Errors (z=-1.56; p < 0.001), Perseverative Errors (z=-0.73; p = 0.002), Non-Perseverative Errors (z=-1.05; p = 0.003) and Conceptual Level Responses (z=-1.52; p < 0.001). Non-Planning Impulsiveness correlated with Performance (ST and TMT).

CONCLUSION

Patients with JME present with impulsive behavior, personality features and executive dysfunction which are linked and may lead to lack of commitment in treatment and affect other aspects of life.

Performance differences between aphasia and healthy aging on an executive function test battery

Purpose: Executive function (EF) deficits commonly co-occur with other linguistic and non-linguistic deficits in aphasia. The questions about whether, and to what extent, people with aphasia (PWA) present deficits on different executive functions (EFs) is relatively understudied.Method: In this study, four EFs, set-switching, updating, inhibition, and dual task processing were evaluated in aphasia and healthy groups. Three groups of participants: 30 healthy young, 30 healthy old, and 10 PWA were assessed on four tasks, Colour Trails Test (CTT 1 and 2), Conners' Continuous Performance Test II (CPT II), n-back (1- and 2-back), and divided attention task that tapped into different EFs. In order to examine performance differences on the EF tasks between the participant groups, repeated measures and multivariate analysis of variances with follow-up pairwise comparisons were computed. Pearson product-moment correlations were conducted to evaluate the strength and direction of the association between aphasia severity (on Western Aphasia Battery-Revised) and executive functioning.Result: PWA demonstrated significantly diminished performance on all EF tasks in comparison to healthy groups and differences were distinct on the higher-level complexity tasks such as the 2-back and CTT 2. The healthy older group demonstrated elevated response times on the CTT, CPT II, and divided attention tasks, and decreased sensitivity scores on the CPT II and n-back in comparison to the younger group. Also, aphasia severity correlated with reduced performance on selective EF measures.Conclusion: This study emphasises the importance of investigating EF deficits in PWA and its potential relationship to language behaviour. Understanding EF is critical for comprehension of linguistic and non-linguistic deficits and in planning treatment for PWA.

Aberrant static and dynamic functional connectivity of the executive control network in lung cancer patients after chemotherapy: a longitudinal fMRI study

OBJECTIVE

The purpose of the current study was to investigate chemotherapy-related variations in the intrinsic static and dynamic functional connectivity (sFC and dFC, respectively) of the executive control network (ECN) in lung cancer patients.

MATERIALS AND METHODS

In this study, we evaluated 18 lung cancer patients scanned before and after adjuvant chemotherapy treatment and compared the patients with 21 healthy controls (HCs). All subjects underwent resting-state functional MRI (rs-fMRI). We constructed the sFC and dFC of the bilateral dorsolateral prefrontal cortex (DLPFC) using a sliding-window approach, and the correlations between the changed sFC or dFC and cognitive performance were analyzed.

RESULTS

Whole-brain sFC analysis showed that the lung cancer patients showed significant FC pattern changes in the bilateral DLPFC, mainly in the bilateral superior frontal gyrus (SFG), bilateral middle frontal gyrus, left superior temporal gyrus, left inferior parietal lobe and the right insula. Furthermore, after chemotherapy, the lung cancer patients showed significantly reduced dFC variability between the right DLPFC and right precuneus compared with HCs. In addition, the decreased dFC between the right DLPFC and left SFG in the lung cancer patients after chemotherapy in state 1 and between the right DLPFC and left insula in the lung cancer patients before chemotherapy in state 2 were negatively correlated with MoCA scores ((r = -0.520, p = 0.039; r = -0.548, p = 0.028, respectively).

CONCLUSIONS

Our results reveal that dynamic connectivity analysis is more effective and sensitive than methods that assume static brain states for linking brain FC patterns and chemotherapy.

Explicit and implicit monitoring in neurodegeneration and stroke

Monitoring is a complex multidimensional neurocognitive phenomenon. Patients with fronto-insular stroke (FIS), behavioural variant frontotemporal dementia (bvFTD) and Alzheimer’s disease (AD) show a lack of self-awareness, insight, and self-monitoring, which translate into anosognosia and daily behavioural impairments. Notably, they also present damage in key monitoring areas. While neuroscientific research on this domain has accrued in recent years, no previous study has compared monitoring performance across these brain diseases and none has applied a multiple lesion model approach combined with neuroimaging analysis. Here, we evaluated explicit and implicit monitoring in patients with focal stoke (FIS) and two types of dementia (bvFTD and AD) presenting damage in key monitoring areas. Participants performed a visual perception task and provided two types of report: confidence (explicit judgment of trust about their performance) and wagering (implicit reports which consisted in betting on their accuracy in the perceptual task). Then, damaged areas were analyzed via structural MRI to identify associations with potential behavioral deficits. In AD, inadequate confidence judgments were accompanied by poor wagering performance, demonstrating explicit and implicit monitoring impairments. By contrast, disorders of implicit monitoring in FIS and bvFTD patients occurred in the context of accurate confidence reports, suggesting a reduced ability to turn self-knowledge into appropriate wagering conducts. MRI analysis showed that ventromedial compromise was related to overconfidence, whereas fronto-temporo-insular damage was associated with excessive wagering. Therefore, joint assessment of explicit and implicit monitoring could favor a better differentiation of neurological profiles (frontal damage vs AD) and eventually contribute to delineating clinical interventions.

Model-based lesion mapping of cognitive control using the Wisconsin Card Sorting Test

The role of the frontal lobes in cognition and behavior has long been enigmatic. Over the past decade, computational models have provided a powerful approach to understanding cognition and decision-making. Here, we used a model-based approach to analyze data from a classical task used to assess frontal lobe function, the Wisconsin Card Sorting Test. We applied computational modeling and voxel-based lesion-symptom mapping in 328 patients with focal lesions, to uncover cognitive processes and neural correlates of test scores. Our results reveal that lesions in the right prefrontal cortex are associated with elevated perseverative errors and reductions in the model parameter of sensitivity to punishment. These findings indicate that the capacity to flexibly switch between task sets requires the detection of contingency changes, which are enabled by a sensitivity to punishment that reduces perseverative errors. We demonstrate the power of model-based approaches in understanding patterns of deficits on classical neuropsychological tasks.

The frontal cortex is involved in cognitive control, e.g. cognitive flexibility and behavioral inhibition, but the roles of frontal subdivisions are unclear. Here, the authors used computational modelling of cognitive control task performance to map lesions responsible for impairments in specific cognitive operations.

Executive (dys)function after stroke: special considerations for behavioral pharmacology

Stroke is a worldwide leading cause of death and long-term disability with concurrent secondary consequences that are largely comprised of mood dysfunction, as well as sensory, motor, and cognitive deficits. This review focuses on the cognitive deficits associated with stroke specific to executive dysfunction (including decision making, working memory, and cognitive flexibility) in humans, nonhuman primates, and additional animal models. Further, we review some of the cellular and molecular underpinnings of the individual components of executive dysfunction and their neuroanatomical substrates after stroke, with an emphasis on the changes that occur during biogenic monoamine neurotransmission. We concentrate primarily on changes in the catecholaminergic (dopaminergic and noradrenergic) and serotonergic systems at the levels of neurotransmitter synthesis, distribution, reuptake, and degradation. We also discuss potential secondary stroke-related behavioral deficits (specifically, poststroke depression as well as drug-abuse potential and addiction) and their relationship with stroke-induced deficits in executive function, an especially important consideration given that the average age of the human stroke population is decreasing. In the final sections, we address pharmacological considerations for the treatment of ischemia and the subsequent functional impairment, as well as current limitations in the field of stroke and executive function research.

Association between executive and food functions in the acute phase after stroke

Purpose To investigate potential associations among executive, physical and food functions in the acute phase after stroke. Methods This is a cross-sectional study that evaluated 63 patients admitted to the stroke unit of a public hospital. The exclusion criteria were other neurological and/or psychiatric diagnoses. The tools for evaluation were: Mini-Mental State Examination and Frontal Assessment Battery for cognitive functions; Alberta Stroke Program Early CT Score for quantification of brain injury; National Institutes of Health Stroke Scale for neurological impairment; Modified Rankin Scale for functionality, and the Functional Oral Intake Scale for food function. Results The sample comprised 34 men (54%) and 29 women with a mean age of 63.6 years. The Frontal Assessment Battery was significantly associated with the other scales. In multivariate analysis, executive function was independently associated with the Functional Oral Intake Scale. Conclusion Most patients exhibited executive dysfunction that significantly compromised oral intake.

White matter integrity in dyskinetic cerebral palsy: Relationship with intelligence quotient and executive function

BACKGROUND

Dyskinetic cerebral palsy (CP) is one of the most disabling motor types of CP and has been classically associated with injury to the basal ganglia and thalamus. Although cognitive dysfunction is common in CP, there is a paucity of published quantitative analyses investigating the relationship between white matter (WM) microstructure and cognition in this CP type.

AIMS

This study aims (1) to compare brain WM microstructure between people with dyskinetic CP and healthy controls, (2) to identify brain regions where WM microstructure is related to intelligence and (3) to identify brain regions where WM microstructure is related to executive function in people with dyskinetic CP and (4) to identify brain regions where the correlations are different between controls and people with CP in IQ and executive functions.

PATIENTS AND METHODS

Thirty-three participants with dyskinetic CP (mean ± SD age: 24.42 ± 12.61, 15 female) were age and sex matched with 33 controls. Participants underwent a comprehensive neuropsychological battery to assess intelligence quotient (IQ) and four executive function domains (attentional control, cognitive flexibility, goal setting and information processing). Diffusion weighted MRI scans were acquired at 3T. Voxel-based whole brain groupwise analyses were used to compare fractional anisotropy (FA) and of the CP group to the matched controls using a general lineal model. Further general linear models were used to identify regions where white matter FA correlated with IQ and each of the executive function domains.

RESULTS

White matter FA was significantly reduced in the CP group in all cerebral lobes, predominantly in regions connected with the parietal and to a lesser extent the temporal lobes. There was no significant correlation between IQ or any of the four executive function domains and WM microstructure in the control group. In participants with CP, lower IQ was associated with lower FA in all cerebral lobes, predominantly in locations that also showed reduced FA compared to controls. Attentional control, goal setting and information processing did not correlate with WM microstructure in the CP group. Cognitive flexibility was associated with FA in regions known to contain connections with the frontal lobe (such as the superior longitudinal fasciculus and cingulum) as well as regions not known to contain tracts directly connected with the frontal lobe (such as the posterior corona radiata, posterior thalamic radiation, retrolenticular part of internal capsule, tapetum, body and splenium of corpus callosum).

CONCLUSION

The widespread loss in the integrity of WM tissue is mainly located in the parietal lobe and related to IQ in dyskinetic CP. Unexpectedly, executive functions are only related with WM microstructure in regions containing fronto-cortical and posterior cortico-subcortical pathways, and not being specifically related to the state of fronto-striatal pathways which might be due to brain reorganization. Further studies of this nature may improve our understanding of the neurobiological bases of cognitive impairments after early brain insult.

Developmental Foreign Accent Syndrome: Report of a New Case

This paper presents the case of a 17-year-old right-handed Belgian boy with developmental FAS and comorbid developmental apraxia of speech (DAS). Extensive neuropsychological and neurolinguistic investigations demonstrated a normal IQ but impaired planning (visuo-constructional dyspraxia). A Tc-99m-ECD SPECT revealed a significant hypoperfusion in the prefrontal and medial frontal regions, as well as in the lateral temporal regions. Hypoperfusion in the right cerebellum almost reached significance. It is hypothesized that these clinical findings support the view that FAS and DAS are related phenomena following impairment of the cerebro-cerebellar network.

Executive Function Deficits in Patients after Cerebellar Neurosurgery

The cerebellum has long been perceived as a structure responsible for the human motor function. According to the contemporary approach, however, it plays a significant role in complex behavior regulatory processes. The aim of this study was to describe executive functions in patients after cerebellar surgery. The study involved 30 patients with cerebellar pathology. The control group comprised 30 neurologically and mentally healthy individuals, matched for sex, age, and number of years of education. Executive functions were measured by the Wisconsin Card Sorting Test (WCST), Stroop Color Word Test (SCWT), Trail Making Test (TMT), and working memory by the Digit Span. Compared to healthy controls, patients made more Errors and Perseverative errors in the WCST, gave more Perseverative responses, and had a lower Number of categories completed. The patients exhibited higher response times in all three parts of the SCWT and TMT A and B. No significant differences between the two groups were reported in their performance of the SCWT and TMT with regard to the measures of absolute or relative interference. The patients had lower score on the backward Digit Span. Patients with cerebellar pathology may exhibit some impairment within problem solving and working memory. Their worse performance on the SCWT and TMT could, in turn, stem from their poor motor-somatosensory control, and not necessarily executive deficits. Our results thus support the hypothesis of the cerebellum's mediating role in the regulation of the activity of the superordinate cognitive control network in the brain. (JINS, 2016, 22, 47-57).

Diversity of approaches in assessment of executive functions in stroke: limited evidence?

Stroke is a leading cause of disability worldwide. Cognitive functions and, in particular, executive function, are commonly affected after stroke, leading to impairments in performance of daily activities, decrease in social participation and in quality of life. Appropriate assessment and understanding of executive dysfunction are important, firstly to develop better rehabilitation strategies for executive functions per se and secondly to consider executive function abilities on rehabilitation strategies in general. The purpose of this review was to identify the most widely used assessment tools of executive dysfunction for patients with stroke, and their psychometric properties.

We systematically reviewed manuscripts published in English in databases from 1999 to 2015. We identified 35 publications. The most frequently used instruments were the Stroop, Digit Span and Trail making tests. Psychometric properties were described for the Executive Function Performance Test, Executive Clock Drawing Task, Chinese Frontal Assessment Battery and Virtual Action Planning — Supermarket, and two subtests of the Cambridge Cognitive Examination — Revised.

There is a paucity of tools to reliably measure executive dysfunction after stroke, despite the fact that executive dysfunction is frequent. Identification of the best tools for executive dysfunction assessment is necessary to address important gaps in research and in clinical practice.

Association between increased magnetic susceptibility of deep gray matter nuclei and decreased motor function in healthy adults

In the human brain, iron is more prevalent in gray matter than in white matter, and deep gray matter structures, particularly the globus pallidus, putamen, caudate nucleus, substantia nigra, red nucleus, and dentate nucleus, exhibit especially high iron content. Abnormally elevated iron levels have been found in various neurodegenerative diseases. Additionally, iron overload and related neurodegeneration may also occur during aging, but the functional consequences are not clear. In this study, we explored the correlation between magnetic susceptibility--a surrogate marker of brain iron--of these gray matter structures with behavioral measures of motor and cognitive abilities, in 132 healthy adults aged 40-83 years. Latent variables corresponding to manual dexterity and executive functions were obtained using factor analysis. The factor scores for manual dexterity declined significantly with increasing age. Independent of gender, age, and global cognitive function, increasing magnetic susceptibility in the globus pallidus and red nuclei was associated with decreasing manual dexterity. This finding suggests the potential value of magnetic susceptibility, a non-invasive quantitative imaging marker of iron, for the study of iron-related brain function changes.

Test Accuracy of Cognitive Screening Tests for Diagnosis of Dementia and Multidomain Cognitive Impairment in Stroke

Background and Purpose—

Guidelines recommend screening stroke-survivors for cognitive impairments. We sought to collate published data on test accuracy of cognitive screening tools.

Methods—

Index test was any direct, cognitive screening assessment compared against reference standard diagnosis of (undifferentiated) multidomain cognitive impairment/dementia. We used a sensitive search statement to search multiple, cross-disciplinary databases from inception to January 2014. Titles, abstracts, and articles were screened by independent researchers. We described risk of bias using Quality Assessment of Diagnostic Accuracy Studies tool and reporting quality using Standards for Reporting of Diagnostic Accuracy guidance. Where data allowed, we pooled test accuracy using bivariate methods.

Results—

From 19 182 titles, we reviewed 241 articles, 35 suitable for inclusion. There was substantial heterogeneity: 25 differing screening tests; differing stroke settings (acute stroke, n=11 articles), and reference standards used (neuropsychological battery, n=21 articles). One article was graded low risk of bias; common issues were case–control methodology (n=7 articles) and missing data (n=22). We pooled data for 4 tests at various screen positive thresholds: Addenbrooke’s Cognitive Examination-Revised (<88/100): sensitivity 0.96, specificity 0.70 (2 studies); Mini Mental State Examination (<27/30): sensitivity 0.71, specificity 0.85 (12 studies); Montreal Cognitive Assessment (<26/30): sensitivity 0.95, specificity 0.45 (4 studies); MoCA (<22/30): sensitivity 0.84, specificity 0.78 (6 studies); Rotterdam-CAMCOG (<33/49): sensitivity 0.57, specificity 0.92 (2 studies).

Conclusions—

Commonly used cognitive screening tools have similar accuracy for detection of dementia/multidomain impairment with no clearly superior test and no evidence that screening tools with longer administration times perform better. MoCA at usual threshold offers short assessment time with high sensitivity but at cost of specificity; adapted cutoffs have improved specificity without sacrificing sensitivity. Our results must be interpreted in the context of modest study numbers: heterogeneity and potential bias.

Cognitive patterns of normal elderly subjects are consistent with frontal cortico-subcortical and fronto-parietal neuropsychological models of brain aging

Three neuropsychological theories have been developed according to a possible existence of a similar pattern of cognitive decline in elderly individuals and patients with brain damage. The respective neuropsychological theories attribute age-related deficits to: (a) dysfunction of the frontal lobes, (b) temporo-parietal dysfunction, or (c) decline of right-hemisphere functions. In the present study, we examined which of these theories best explains the cognitive patterns of normal elderly subjects older than 80 years of age (old elderly). Thirty normal old elderly subjects, 14 patients with subcortical vascular dementia, 14 with mild Alzheimer's disease, 15 with damage of the right hemisphere of the brain, and 20 young elderly controls participated. A test battery covering the main cognitive domains was administered to all participants. A hierarchical cluster analysis revealed five groups of individuals with different cognitive patterns across the whole sample. Old elderly subjects were assigned to four groups according to: (a) preserved overall cognitive performance, (b) processing speed decline, (c) attention decline, or (d) executive impairment. The results of the study are most congruent with models emphasizing frontal-lobe cortical-subcortical and fronto-parietal changes in old age. The results also indicate considerable heterogeneity in the cognitive patterns of normal old elderly adults.