Discriminability of the Wisconsin Card Sorting Test using the standardization sample

The limitations and challenges in the assessment of executive dysfunction associated with real-world functioning: The opportunity of serious games

Nowadays, there is a broad range of methods for detecting and evaluating executive dysfunction ranging from clinical interview to neuropsychological evaluation. Nevertheless, a critical issue of these assessments is the lack of correspondence of the neuropsychological test's results with real-world functioning. This paper proposes serious games as a new framework to improve the neuropsychological assessment of real-world functioning. We briefly discuss the contribution and limitations of current methods of evaluation of executive dysfunction (paper-and-pencil tests, naturalistic observation methods, and Information and Communications Technologies) to inform on daily life functioning. Then, we analyze what are the limitations of these methods to predict real-world performance: (1) A lack of appropriate instruments to investigate the complexity of real-world functioning, (2) the vast majority of neuropsychological tests assess well-structured tasks, and (3) measurement of behaviors are based on simplistic data collection and statistical analysis. This work shows how serious games offer an opportunity to develop more efficient tools to detect executive dysfunction in everyday life contexts. Serious games provide meaningful narrative stories and virtual or real environments that immerse the user in natural and social environments with social interactions. In those highly interactive game environments, the player needs to adapt his/her behavioral performance to novel and ill-structured tasks which are suited for collecting user interaction evidence. Serious games offer a novel opportunity to develop better tools to improve diagnosis of the executive dysfunction in everyday life contexts. However, more research is still needed to implement serious games in everyday clinical practice.

Exploring behavioural and cognitive dysexecutive syndrome in patients with focal prefrontal cortex damage

This study's objectives were to characterize the frequency and profile of behavioral and cognitive dysexecutive syndromes in patients with focal prefrontal cortex damage and how these syndromes overlap. We also examined the contribution of the prefrontal brain regions to these syndromes. Therefore, thirty patients with prefrontal cortex damage and thirty control subjects were compared on their performances using the GREFEX battery assessing the dysexecutive syndromes. The results showed that combined behavioral and cognitive dysexecutive syndrome was observed in 53.33%, while pure cognitive dysexecutive syndrome was observed in 20% and behavioral in 26.67%. Also, almost all behavioral and cognitive dysexecutive disorders discriminated frontal patients from controls. Moreover, correlations and regression analyses between task scores in both domains of dysexecutive syndromes showed that the spectrum of behavioral disorders was differentially associated with cognitive impairment of initiation, inhibition, generation, deduction, coordination, flexibility and the planning process. Furthermore, the patterns of cognitive and behavioral dysexecutive syndrome were both predictors of impairment in daily living activities and loss of autonomy. Finally, frontal regions contributing to different dysexecutive syndromes assessed by MRI voxel lesion symptom analysis indicate several overlapping regions centered on the ventromedial and dorsomedial prefrontal cortex for both domains of dysexecutive syndrome. This study concludes that damage to the frontal structures may lead to a diverse set of changes in both cognitive and behavioral domains which both contribute to loss of autonomy. The association of the ventromedial and dorsomedial prefrontal regions to both domains of dysexecutive syndrome suggests a higher integrative role of these regions in processing cognition and behavior.

Cognitive impairment in Chinese adult patients with type III spinal muscular atrophy without disease-modifying treatment

Objective

Spinal muscular atrophy (SMA) is a neurodegenerative disorder characterized by the degeneration of motor neurons in the spinal cord. It remains uncertain whether the cognitive performance of adult patients with SMA is impaired. The objective of this study was to assess the cognitive profile of adult Chinese patients with SMA and the association between clinical features and cognitive ability, particularly executive function.

Methods

This cross-sectional study included 22 untreated adult patients with type III SMA and 20 healthy subjects. The following variables were assessed: general intelligence, memory, attention, language, executive function, depression, anxiety, and other demographic and clinical parameters. In addition, physical function was evaluated using the Hammersmith Functional Motor Scale Expanded (HFMSE), the Revised Upper Limb Module (RULM), and the 6-Minute Walk Test (6MWT).

Results

SMA patients had lower scores than healthy subjects in the Verbal Fluency Test, Stroop effect, Total Errors, Perseverative Responses, Perseverative Errors, and Non-perseverative Errors in the Wisconsin Card Sorting Test, showing impaired abilities of SMA patients in executive function. In the Attention Network Test (ANT), the results indicated that the SMA patients also had selective deficits in their executive control networks. Ambulant patients had better executive function test performance than non-ambulant ones. Compromised executive abilities in patients with SMA were correlated with a younger age at onset, poorer motor function, and higher levels of anxiety and depression.

Conclusion

Our study presented the distribution of cognitive impairment in a Chinese cohort with SMA. Patients with type III SMA showed selective deficits in executive function, which may be associated with disease severity, physical impairment, depression and anxiety. Future cognitive studies, accounting for motor and emotional impairment, are needed to evaluate if executive impairment is driven by specific brain changes or by those confounding factors.

Iron supplementation given to nonanemic infants: neurocognitive functioning at 16 years

OBJECTIVE

There is concern that high iron uptake during the critical period of early brain development carries potential risks, especially for nonanemic infants. This study examined the neurocognitive functioning of 16-year-olds who were nonanemic as infants and received iron supplementation.

METHODS

We studied 562 Chilean adolescents (M 16.2 years; 52.7% female) who participated in a randomized controlled iron supplementation trial in infancy. Between 6 and 12 months, 346 consumed an iron-fortified formula (12.7 Fe mg/L) or, if primarily breastfed, liquid vitamins with 15 mg elemental iron as ferrous sulfate, and 216 consumed unmodified cow milk without iron or liquid vitamins without iron if primarily breastfed.

RESULTS

Compared to adolescents in the no-added iron condition in infancy, those in the iron-supplemented condition had poorer visual-motor integration, quantitative reasoning skills, and incurred more errors on neurocognitive tasks. Consuming larger amounts of iron-fortified formula in infancy was associated with lower arithmetic achievement. Of adolescents who had high hemoglobin at 6 months (Hb ≥ 125 g/L), those in the iron supplemented condition had poorer performance on arithmetic, quantitative reasoning, and response inhibition tests than those in the no-added iron condition. Of adolescents who had marginally low 6-month hemoglobin (Hb > 100 and < 110 g/L), those who received no-added iron incurred more errors on a visual searching task than those in the iron-supplemented condition.

CONCLUSION

The physiologic need for iron during the period of rapid and critical brain development in young infants should be considered vis-à-vis the risks associated with supplementing nonanemic infants with high levels of iron.Clinical Trials number: NCT01166451.

Multidimensional Clinical Assessment in Frontotemporal Dementia and Its Spectrum in Latin America and the Caribbean: A Narrative Review and a Glance at Future Challenges

Frontotemporal dementia (FTD) is the third most common form of dementia across all age groups and is a leading cause of early-onset dementia. The Frontotemporal dementia (FTD) includes a spectrum of diseases that are classified according to their clinical presentation and patterns of neurodegeneration. There are two main types of FTD: behavioral FTD variant (bvFTD), characterized by a deterioration in social function, behavior, and personality; and primary progressive aphasias (PPA), characterized by a deficit in language skills. There are other types of FTD-related disorders that present motor impairment and/or parkinsonism, including FTD with motor neuron disease (FTD-MND), progressive supranuclear palsy (PSP), and corticobasal syndrome (CBS). The FTD and its associated disorders present great clinical heterogeneity. The diagnosis of FTD is based on the identification through clinical assessments of a specific clinical phenotype of impairments in different domains, complemented by an evaluation through instruments, i.e., tests and questionnaires, validated for the population under study, thus, achieving timely detection and treatment. While the prevalence of dementia in Latin America and the Caribbean (LAC) is increasing rapidly, there is still a lack of standardized instruments and consensus for FTD diagnosis. In this context, it is important to review the published tests and questionnaires adapted and/or validated in LAC for the assessment of cognition, behavior, functionality, and gait in FTD and its spectrum. Therefore, our paper has three main goals. First, to present a narrative review of the main tests and questionnaires published in LAC for the assessment of FTD and its spectrum in six dimensions: (i) Cognitive screening; (ii) Neuropsychological assessment divided by cognitive domain; (iii) Gait assessment; (iv) Behavioral and neuropsychiatric symptoms; (v) Functional assessment; and (vi) Global Rating Scale. Second, to propose a multidimensional clinical assessment of FTD in LAC identifying the main gaps. Lastly, it is proposed to create a LAC consortium that will discuss strategies to address the current challenges in the field.

The neural substrate and underlying mechanisms of executive control fluctuations in primates

Trial-by-trial alterations in response time have been linked to fluctuations of executive control and transient lapses of attention. Here, we report remarkable homologies in performance-dependent fluctuations of response time between humans and monkeys. We examined the effects of selective bilateral lesions in four frontal regions on control fluctuations in the context of a rule-shifting task. Lesions within orbitofrontal cortex (OFC), but not within superior-lateral prefrontal cortex, significantly exaggerated the performance-dependent fluctuations of control and prevented its restoration following feedback. Lesions within dorsolateral prefrontal cortex (DLPFC) or within anterior-cingulate cortex (ACC) led to instability of control and disruption of its link with monkeys' upcoming decisions. Examining the activity of DLPFC and OFC cells shed more lights on the underlying neuronal mechanisms by showing that before the start of each trial, OFC cell activity conveyed detailed information regarding the current state of executive control and the likelihood of success or failure in the future decisions. This further emphasizes the crucial role of OFC in the trial-by-trial allocation (setting) of control to the ongoing task. These findings bring insights to the neural architecture of executive control in primates and suggest that DLPFC and ACC support sustained executive control, but OFC is more involved in setting and restoring the control.

Executive Functions in Predicting Weight Loss and Obesity Indicators: A Meta-Analysis

While previous studies have suggested that there exists a relationship between obesity and executive function (EF), the mechanisms and causal relationship between them remain unclear. There are important clinical implications of determining whether EF can predict and treat obesity. We conducted a multilevel meta-analysis of randomized controlled trials (RCTs) and longitudinal studies. Specifically, we investigate (a) whether EF interventions have an effect on weight loss, (b) whether baseline EF can be a predictor of future weight loss through obesity intervention, and (c) whether early-life EF can predict future weight loss. Eight RCTs and 17 longitudinal studies with a total of 11,393 participants were identified. We found that (a) EF interventions may not have an effect on weight loss, (b) baseline inhibition (β = 0.259, p = 0.03) and delay discounting (β = −0.17, p = 0.04) significantly predict future weight loss through obesity intervention, (c) age (F = 13.666, p = 0.005) moderates the relationship between working memory and weight loss through intervention, but not weight status, type of intervention, and percentage of female, and (d) early life inhibition (β = 0.185, p = 0.07) is a marginally significant predictor of future weight loss. Our results seem to support the assumption that the relationship between EF and obesity is not direct, and a higher-order factor, such as genes, may link obesity and EF. Building on the preliminary findings, further studies focusing on EF and obesity are needed in the future.

The Efficacy, Feasibility And Acceptability Of A Remotely Accessible Use Of CIRCuiTS, A Computerized Cognitive Remediation Therapy Program For Schizophrenia: A Pilot Study

INTRODUCTION

The Computerized Interactive Remediation of Cognition - Training for Schizophrenia (CIRCuiTS) is a form of cognitive remediation therapy developed to target neurocognitive and metacognitive deficits of people with schizophrenia, which have a detrimental impact on real-life functioning. The English version of CIRCuiTS demonstrated good acceptability and feasibility. A recent randomized controlled trial provided evidence that the program improves memory and functioning, and that the impact on functional outcome is mediated by metacognition. The next steps in the development of CIRCuiTS include both: 1) the translation and adaptation of the program in different cultural settings; and 2) the demonstration of feasibility, acceptability and effectiveness of a standardized method to administer CIRCuiTS remotely.

PURPOSE

To implement the CIRCuiTS Italian version and to assess acceptability, feasibility and efficacy of a standardized method to administer CIRCuiTS remotely.

METHODS

Participants were assessed at baseline and received up to 40 CIRCuiTS therapy sessions, three times a week, for about 1 hr over a three-month period. Participants were reassessed post-treatment.

RESULTS

The program demonstrated good feasibility and high acceptability when assessed by the number of dropouts and evaluation of patients' satisfaction. Participants improved in learning, speed of processing, working memory and executive control. They showed a reduction in disorganization and improvement in self-esteem, functional capacity, and real-life functioning.

CONCLUSION

In this study, a standardized protocol for using CIRCuiTS from home was implemented. The first set of data showed in the paper is encouraging. The proposed procedure could lead to a dropout reduction while maintaining the efficacy of the program.

ALDH2 modulated changes in cytokine levels and cognitive function in bipolar disorder: A 12-week follow-up study

OBJECTIVES

We investigated the association of the aldehyde dehydrogenase 2 ( ALDH2) polymorphism (rs671), which is involved with the dopaminergic function, and with changes in cytokine levels and cognitive function, in a 12-week follow-up study in patients with bipolar disorder.

METHODS

Patients with a first diagnosis of bipolar disorder were recruited. Symptom severity and levels of plasma cytokines (tumor necrosis factor α, C-reactive protein, interleukin 6 and transforming growth factor β1) were examined during weeks 0, 1, 2, 4, 8 and 12. Neurocognitive function was evaluated at baseline and endpoint. The ALDH2 polymorphism genotype was determined.

RESULTS

A total of 541 patients with bipolar disorder were recruited, and 355 (65.6%) completed the 12-week follow-up. A multiple linear regression analysis showed a significant ( p = 0.000226) association between the ALDH2 polymorphism and changes in C-reactive protein levels. Different aspects of cognitive function improved in patients with different ALDH2 genotypes. Only patients with the ALDH2*1*1 genotype showed significant correlations between improvement of cognitive function and increased transforming growth factor -β1.

CONCLUSION

The ALDH2 gene might influence changes in cytokine levels and cognitive performance in patients with bipolar disorder. Additionally, changes in cytokine levels and cognitive function were correlated only in patients with specific ALDH2 genotypes.

Long-term heroin use was associated with the downregulation of systemic platelets, BDNF, and TGF-β1, and it contributed to the disruption of executive function in Taiwanese Han Chinese

BACKGROUND

Long-term heroin addicts have low plasma brain-derived neurotrophic factor (BDNF) levels. However, the mechanisms and effects of systemic disturbances of BDNF caused by heroin remain unclear.

OBJECTIVE

Blood platelet might be a source of neurotrophic factors like BDNF and transforming growth factor (TGF)-β1. Thus, we investigated the effects of heroin on platelets, BDNF and TGF-β1, the association between blood platelets, BDNF, TGF-β1, and executive function in long-term heroin addicts.

METHODS

We enrolled 170 heroin addicts and 141 healthy controls. We measured their plasma BDNF and TGF-β1 levels and counted their platelets, red and white blood cells. The Wisconsin Card Sorting Test (WCST) was used to assess their executive function.

RESULTS

Plasma BDNF and TGF-β1 levels were significantly downregulated in long-term heroin addicts. BDNF, TGF-β1, and platelet levels were lower in patients who had used heroin for more than 6 years than in those who had used it for less than 6 years. Lower plasma BDNF and TGF-β1 levels were highly correlated with the changes in platelet counts. In the WCST, the number of trials needed to complete the first category were negatively associated with platelet counts and BDNF levels.

CONCLUSIONS

In long-term heroin addicts, lower platelet counts contributed to lower plasma BDNF and TGF-β1 levels, which, in turn, contributed to the disruption of executive function after long-term heroin use. Neurotrophic- and platelet-protective agents might provide a useful research focus for heroin addiction therapy.

Problem-solving styles in autism spectrum disorder and the development of higher cognitive functions

The Vygotsky Blocks Test assesses problem-solving styles within a theoretical framework for the development of higher mental processes devised by Vygotsky. Because both the theory and the associated test situate cognitive development within the child's social and linguistic context, they address conceptual issues around the developmental relation between language and thought that are pertinent to development in autism. Our aim was to document the performance of adults with autism spectrum disorder on the Vygotsky Blocks Test, and our results showed that they made more errors than the typically developing participants and that these errors correlated with performance IQ. The autism spectrum disorder group also required more cues than the typically developing group to discern the conceptual structure of the blocks, a pattern that correlated with Autism Diagnostic Observational Schedule-Communication and Imagination/Creativity sub-scales. When asked to categorize the blocks in new ways, the autism spectrum disorder participants developed fewer principles on which to base new categorizations, which in contrast to the typically developing group correlated with verbal IQ and with the Imagination/Creativity sub-scale of the ADOS. These results are in line with a number of existing findings in the autism spectrum disorder literature and confirm that conceptualization in autism spectrum disorder seems to rely more on non-verbal and less on imaginative processes than in typically developing individuals. The findings represent first steps to the possibility of outlining a testable account of psychological development in autism spectrum disorder that integrates verbal, non-verbal and social factors into the transition from elementary to higher level processes.

The correlation between plasma brain-derived neurotrophic factor and cognitive function in bipolar disorder is modulated by the BDNF Val66Met polymorphism

We explored the effect of the Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism (rs6265) on correlation between changes in plasma BDNF levels with cognitive function and quality of life (QoL) after 12 weeks of treatment in bipolar disorder (BD). Symptom severity and plasma BDNF levels were assessed upon recruitment and during weeks 1, 2, 4, 8 and 12. QoL, the Wisconsin Card Sorting Test (WCST), and the Conners’ Continuous Performance Test (CPT) were assessed at baseline and endpoint. The BDNF Val66Met polymorphism was genotyped. Changes in cognitive function and QoL over 12 weeks were reduced using factor analysis for the evaluation of their correlations with changes in plasma BDNF. Five hundred forty-one BD patients were recruited and 65.6% of them completed the 12-week follow-up. Changes in plasma BDNF levels with factor 1 (WCST) were significantly negatively correlated (r = −0.25, p = 0.00037). After stratification of BD subtypes and BDNF genotypes, this correlation was significant only in BP-I and the Val/Met genotype (r = −0.54, p = 0.008). We concluded that changes in plasma BDNF levels significantly correlated with changes in WCST scores in BD and is moderated by the BDNF Val66Met polymorphism and the subtype of BD.

A Test for Children's Goal-Directed Behavior: A Pilot Study

A test for children's goal-directed behavior was developed, based on neuropsychological executive function research of Vilkki and Holst and on the framework of Lewin's level-of-aspiration research. 46 12-yr.-old children were participants. Fluid Intelligence was expected to be linked to goal-directed behavior and a commonly used executive function task, the Wisconsin Card-sorting Test. A child was asked to set personal goals in a short-term memory task without prior knowledge about performance. Four different task versions were developed employing both verbal (memorizing series of words) and visuospatial (memorizing block sequences) material. The child set an individual goal for each memory trial. Goal-setting after successful and failed trials was investigated. Usually, the children lowered their goals after failures and set their goals higher or did not change them after successful trials. Compared to goal on a previous trial, Inadequate Responses included setting a goal higher after a failed trial and setting it lower after success. Fluid Intelligence was related to goal-directed behavior, viz., Inadequate Responses. It also correlated with scores on the Wisconsin Card-sorting Test. The results are in concordance with previous research. In addition to experimental executive function research, the novel test might be useful in research concerning children's motivation, self-efficacy, and self-regulated learning.

Sensitivity and specificity of executive function tests for Alzheimer's disease

Decline in executive function (EF) occurs early in Alzheimer's disease (AD) and can interfere with daily functioning. Unfortunately, little is known about the relative ability of traditional EF tests to detect these cognitive changes. Given that timely diagnosis and intervention are essential to improving functional outcome in this population, our aim was to identify the specific EF measures that best differentiated mild dementia from normal aging. Thirty-one patients with mild AD and 31 controls were administered 7 EF tests. Findings indicated significant between-group differences on all measures except Wisconsin Card Sorting Test. The remaining 6 tests displayed fair to good accuracy discriminating between AD cases and controls. Only category fluency and Tower of London test remained in the final regression model that yielded the highest AUC of 0.90, which was not statistically different from that of either test alone. Overall, most of the tests employed were valid for assessing mild EF disturbances. Specifically, the two measures can be used in isolation for quick screening or in combination to facilitate a more in-depth evaluation of EF performance. This study contributes to clinical field by testifying to the validity of various EF tests to identify AD-related compromises in this cognitive domain.

Combining Partial Directed Coherence and Graph Theory to Analyse Effective Brain Networks of Different Mental Tasks

PURPOSE

The aim of this study is to qualify the network properties of the brain networks between two different mental tasks (play task or rest task) in a healthy population.

METHODS AND MATERIALS

EEG signals were recorded from 19 healthy subjects when performing different mental tasks. Partial directed coherence (PDC) analysis, based on Granger causality (GC), was used to assess the effective brain networks during the different mental tasks. Moreover, the network measures, including degree, degree distribution, local and global efficiency in delta, theta, alpha, and beta rhythms were calculated and analyzed.

RESULTS

The local efficiency is higher in the beta frequency and lower in the theta frequency during play task whereas the global efficiency is higher in the theta frequency and lower in the beta frequency in the rest task.

SIGNIFICANCE

This study reveals the network measures during different mental states and efficiency measures may be used as characteristic quantities for improvement in attentional performance.

Quantitative electroencephalographic and neuropsychological investigation of an alternative measure of frontal lobe executive functions: the Figure Trail Making Test

The most frequently used measures of executive functioning are either sensitive to left frontal lobe functioning or bilateral frontal functioning. Relatively little is known about right frontal lobe contributions to executive functioning given the paucity of measures sensitive to right frontal functioning. The present investigation reports the development and initial validation of a new measure designed to be sensitive to right frontal lobe functioning, the Figure Trail Making Test (FTMT). The FTMT, the classic Trial Making Test, and the Ruff Figural Fluency Test (RFFT) were administered to 42 right-handed men. The results indicated a significant relationship between the FTMT and both the TMT and the RFFT. Performance on the FTMT was also related to high beta EEG over the right frontal lobe. Thus, the FTMT appears to be an equivalent measure of executive functioning that may be sensitive to right frontal lobe functioning. Applications for use in frontotemporal dementia, Alzheimer’s disease, and other patient populations are discussed.

Measurement of latent cognitive abilities involved in concept identification learning

INTRODUCTION

We used cognitive and psychometric modeling techniques to evaluate the construct validity and measurement precision of latent cognitive abilities measured by a test of concept identification learning: the Penn Conditional Exclusion Test (PCET).

METHOD

Item response theory parameters were embedded within classic associative- and hypothesis-based Markov learning models and were fitted to 35,553 Army soldiers' PCET data from the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS).

RESULTS

Data were consistent with a hypothesis-testing model with multiple latent abilities-abstraction and set shifting. Latent abstraction ability was positively correlated with number of concepts learned, and latent set-shifting ability was negatively correlated with number of perseverative errors, supporting the construct validity of the two parameters. Abstraction was most precisely assessed for participants with abilities ranging from 1.5 standard deviations below the mean to the mean itself. Measurement of set shifting was acceptably precise only for participants making a high number of perseverative errors.

CONCLUSIONS

The PCET precisely measures latent abstraction ability in the Army STARRS sample, especially within the range of mildly impaired to average ability. This precision pattern is ideal for a test developed to measure cognitive impairment as opposed to cognitive strength. The PCET also measures latent set-shifting ability, but reliable assessment is limited to the impaired range of ability, reflecting that perseverative errors are rare among cognitively healthy adults. Integrating cognitive and psychometric models can provide information about construct validity and measurement precision within a single analytical framework.

Identifying cognitive remediation change through computational modelling--effects on reinforcement learning in schizophrenia

OBJECTIVE

Converging research suggests that individuals with schizophrenia show a marked impairment in reinforcement learning, particularly in tasks requiring flexibility and adaptation. The problem has been associated with dopamine reward systems. This study explores, for the first time, the characteristics of this impairment and how it is affected by a behavioral intervention-cognitive remediation.

METHOD

Using computational modelling, 3 reinforcement learning parameters based on the Wisconsin Card Sorting Test (WCST) trial-by-trial performance were estimated: R (reward sensitivity), P (punishment sensitivity), and D (choice consistency). In Study 1 the parameters were compared between a group of individuals with schizophrenia (n = 100) and a healthy control group (n = 50). In Study 2 the effect of cognitive remediation therapy (CRT) on these parameters was assessed in 2 groups of individuals with schizophrenia, one receiving CRT (n = 37) and the other receiving treatment as usual (TAU, n = 34).

RESULTS

In Study 1 individuals with schizophrenia showed impairment in the R and P parameters compared with healthy controls. Study 2 demonstrated that sensitivity to negative feedback (P) and reward (R) improved in the CRT group after therapy compared with the TAU group. R and P parameter change correlated with WCST outputs. Improvements in R and P after CRT were associated with working memory gains and reduction of negative symptoms, respectively.

CONCLUSION

Schizophrenia reinforcement learning difficulties negatively influence performance in shift learning tasks. CRT can improve sensitivity to reward and punishment. Identifying parameters that show change may be useful in experimental medicine studies to identify cognitive domains susceptible to improvement.

The kynurenine pathway contributes to long-term neuropsychological changes in experimental pneumococcal meningitis

Pneumococcal meningitis is a lethal form of bacterial infection in the central nervous system that often causes lifelong neurological sequelae, despite therapeutic advances. The contemporary view is that the inflammatory response to infection contributes to the functional disabilities among survivors of this disease. We previously have established a mouse model of neurobehavioural deficits, using an automated IntelliCage™ system that revealed long-term behavioural and cognitive deficits in C57BL/6J female mice cured of meningitis by ceftriaxone treatment. We now have investigated the roles of two kynurenine pathway enzymes, indoleamine dioxygenase-1 (IDO1) and tryptophan dioxygenase-2 (TDO2), in the pathomechanisms of pneumococcal meningitis. Since tryptophan metabolism has long been implicated in behavioural and cognitive modulation through the production of neuroactive compounds, we hypothesised that preventing the actions of these enzymes through gene knockout would be beneficial in mice subjected to pneumococcal infection. We found no significant effect of IDO1 or TDO2 on mortality. Post-meningitic wild-type mice showed long-term diurnal hypoactivity and nocturnal hyperactivity when they were exposed to an Intellicage adaptation test throughout both the light and dark phases. These changes were not apparent in IDO1(-/-) survivors, but were present in the TDO2(-/-) survivors. Both IDO1(-/-) and TDO2(-/-) survivors were not protected against developing long-term cognitive deficits as measured in IntelliCage-based patrolling or reversal tasks. Collectively, these observations suggest (i) involvement of the kynurenine pathway in causing some behavioural sequelae of pneumococcal meningitis and (ii) that this pathway might operate synergistically with, or independently of, other pathways to cause other aspects of neurological sequelae.

Neurocognitive effects of aripiprazole in adolescents and young adults with schizophrenia

BACKGROUND

The use of aripiprazole has been associated with a positive influence on mood and improved cognitive skills and social interactions; however, studies of its effects on young schizophrenic patients have been limited to active symptoms.

AIMS

This prospective, open-label study investigated the neurocognitive effects of aripiprazole in adolescents and young adults with first and repeated episodes of schizophrenia.

METHODS

Twenty-three of 42 schizophrenic outpatients aged 12-26 completed a trial of aripiprazole, and its efficacy was determined using the Brief Psychiatric Rating Scale (BPRS), Clinical Global Impressions Severity (CGI-S) and WHO Quality of Life (WHOQOL) scales. Cognitive function was measured with the Cognitive Performance Test (CPT) and Wisconsin Card Sorting Test (WCST) at 4, 12 and 24 weeks of treatment.

RESULTS

Results showed statistically significant improvements in BPRS, CGI-S and WHOQOL scores in certain (but not all) subcategories of cognitive measures including CPT detectability and total errors and perseverative errors on the WCST. There were few adverse side-effects.

CONCLUSIONS

Psychotic symptoms and cognitive skills improved during treatment with aripiprazole in adolescents and young adults with schizophrenia. Patients with first psychotic episodes did better than did those with repeat episodes.

Neural substrates for heightened anxiety in children with brain tumors

This study investigated anxiety symptoms' associations with cognitive functioning and tumor locus in pediatric brain tumor patients. Data from 91 patients were collected as part of a neuropsychological assessment. Significant relationships were found between anxiety symptoms and mental set shifting (Wisconsin Card Sorting). Analyses revealed patients with right cortical tumors or left cerebellar tumors had significantly greater anxiety than those with midline/bilateral tumor and those with left cortical or right cerebellar tumors. Results support the specific risk of anxiety with right cortical and left cerebellar tumors. Results highlight the association of anxiety and one important element of executive functioning.

Autonomic regulation predicts performance on Wisconsin Card Sorting Test (WCST) in adults with schizophrenia

Although executive functions have been associated with autonomic regulatory capacity in healthy adults, there appear to be no reports of these relations in adults with schizophrenia to date. We tested whether baseline autonomic regulation was associated with performance on the Wisconsin Card Sorting Test (WCST) in a group of 42 stable community outpatients with schizophrenia. Patients exhibited faster resting heart rates and lower respiratory sinus arrhythmia (RSA) than age-matched controls, consistent with previous research. Patients also completed relatively few WCST categories and made many perseverative errors, replicating prior studies. Within the patient group, relatively better WCST performance was associated with slower resting heart rate and higher RSA, suggesting that inefficient executive and autonomic functioning in schizophrenia may be linked. WCST performance and autonomic regulatory capacity were further reduced in a subset of patients receiving clozapine, but relations between WCST performance and autonomic regulatory parameters did not differ from those of other patients. Findings extend the neurovisceral integration model of autonomic regulation to adults with schizophrenia and attest to the reliability of the model.

The ecological and construct validity of a newly developed measure of executive function: the Virtual Library Task

Virtual reality (VR) assessment paradigms have the potential to address the limited ecological validity of pen and paper measures of executive function (EF) and the pragmatic and reliability issues associated with functional measures. To investigate the ecological validity and construct validity of a newly developed VR measure of EF, the Virtual Library Task (VLT); a real life analogous task--the Real Library Task (RLT); and five neuropsychological measures of EF were administered to 30 patients with traumatic brain injury (TBI) and 30 healthy Controls. Significant others for each participant also completed the Dysexecutive Questionnaire (DEX), which is a behavioral rating scale of everyday EF. Performances on the VLT and the RLT were significantly positively correlated indicating that VR performance is similar to real world performance. The TBI group performed significantly worse than the Control group on the VLT and the Modified Six Elements Test (MSET) but the other four neuropsychological measures of EF failed to differentiate the groups. Both the MSET and the VLT significantly predicted everyday EF suggesting that they are both ecologically valid tools for the assessment of EF. The VLT has the advantage over the MSET of providing objective measurement of individual components of EF.

Operating characteristics of executive functioning tests following traumatic brain injury

The primary purposes of this study were to determine if controls, and mild and moderate/severe traumatic brain injury (TBI) patients performed differently on a battery of executive functioning (EF) tests, and to identify the operating characteristics of EF tests in this population. Participants consisted of 46 brain-injured individuals and 24 healthy controls. All participants completed an extensive battery of EF tests. Results showed that mild TBI participants performed worse than controls on the Trail Making Test Part B, and that moderate/severe TBI participants consistently performed worse than either group on a variety of EF measures. Tests of EF exhibited a wide range of operating characteristics, suggesting that some EF tests are better than others in identifying TBI-related neurocognitive impairment. Predictive values were better for individuals with moderate/severe TBI than mild TBI. Overall, the Digit Span Backward Test showed the best positive predictive power in differentiating TBI. Our results provide useful data that may guide test selection in evaluating EF in patients with traumatic brain injury.

Does gender influence cognitive outcome after traumatic brain injury?

The aim of this study was to determine whether males and females differ in post-acute cognitive outcome following traumatic brain injury (TBI). Performances of 83 men and 75 women with mild to severe TBI were compared on measures of cognitive functions typically impacted by TBI (i.e., processing speed, executive functioning, and memory). Participants completed selected subtests of the Cambridge Neuropsychological Test Automated Battery (CANTAB). Among the participants with mild TBI, women scored significantly higher than men on a test of visual memory. There were no other significant gender differences in cognitive outcomes. These findings overall suggest that cognitive outcome after TBI does not differ according to gender, with the possible exception of memory functioning. Further research is needed to replicate this finding and determine which moderating variables may impact on the relationship between gender and cognitive outcome after TBI.

The Wisconsin Card Sorting Test and the cognitive assessment of prefrontal executive functions: a critical update

For over four decades the Wisconsin Card Sorting Test (WCST) has been one of the most distinctive tests of prefrontal function. Clinical research and recent brain imaging have brought into question the validity and specificity of this test as a marker of frontal dysfunction. Clinical studies with neurological patients have confirmed that, in its traditional form, the WCST fails to discriminate between frontal and non-frontal lesions. In addition, functional brain imaging studies show rapid and widespread activation across frontal and non-frontal brain regions during WCST performance. These studies suggest that the concept of an anatomically pure test of prefrontal function is not only empirically unattainable, but also theoretically inaccurate. The aim of the present review is to examine the causes of these criticisms and to resolve them by incorporating new methodological and conceptual advances in order to improve the construct validity of WCST scores and their relationship to prefrontal executive functions. We conclude that these objectives can be achieved by drawing on theory-guided experimental design, and on precise spatial and temporal sampling of brain activity, and then exemplify this using an integrative model of prefrontal function [i.e., Miller, E. K. (2000). The prefrontal cortex and cognitive control. Nature Reviews Neuroscience, 1, 59-65.] combined with the formal information theoretical approach to cognitive control [Koechlin, E., & Summerfield, C. (2007). An information theoretical approach to prefrontal executive function. Trends in Cognitive Sciences, 11, 229-235.].

Gender differences in executive functions following traumatic brain injury

The present study used the National Institute on Disability Rehabilitation and Research (NIDRR) funded Traumatic Brain Injury Model Systems (TBIMS) database to examine the effect of gender on presentation of executive dysfunction following traumatic brain injury (TBI) and variables that might impact the course and degree of recovery. The Wisconsin Card Sort Test (WCST) was chosen as a measure of executive function which has good credentials without reports of gender effects. Female subjects performed significantly better on the WCST than male subjects as shown by analyses of variance on scores of 1,331 patients for Categories Achieved (means for females = 4.09, males = 3.67, p = .003) and Perseverative Responses (means for females = 32.17, males = 36.42, p = .003). Outperformance by females was also noted in additional ANOVAs examining the interaction of education and gender, and ethnicity and gender in relation to Categories Achieved (p < .01), and for ethnicity and gender in relation to Perseverative Responses (p < .01). A multiple logistic regression revealed that gender, minority status, education level, history of illicit drug use, cause of injury, and length of coma each contributed uniquely to predicting Categories Achieved on the WCST. Simple logistic regression analyses showed that, of these variables, gender and cause of injury (violent vs. non-violent) were the strongest predictors. In contrast, when examining Perseverative Responses, regression analyses found gender, minority status and length of coma predicted impairment. Simple logistic regression analyses showed that, of these three variables, gender and minority status were most robust in predicting impaired Perseverative Responses scores. Implications of these findings are discussed and recommendations for further research are offered.

Older adults with cognitive complaints show brain atrophy similar to that of amnestic MCI

OBJECTIVE

To examine the neural basis of cognitive complaints in healthy older adults in the absence of memory impairment and to determine whether there are medial temporal lobe (MTL) gray matter (GM) changes as reported in Alzheimer disease (AD) and amnestic mild cognitive impairment (MCI).

METHODS

Participants were 40 euthymic individuals with cognitive complaints (CCs) who had normal neuropsychological test performance. The authors compared their structural brain MRI scans to those of 40 patients with amnestic MCI and 40 healthy controls (HCs) using voxel-based morphometry and hippocampal volume analysis.

RESULTS

The CC and MCI groups showed similar patterns of decreased GM relative to the HC group on whole brain analysis, with differences evident in the MTL, frontotemporal, and other neocortical regions. The degree of GM loss was associated with extent of both memory complaints and performance deficits. Manually segmented hippocampal volumes, adjusted for age and intracranial volume, were significantly reduced only in the MCI group, with the CC group showing an intermediate level.

CONCLUSIONS

Cognitive complaints in older adults may indicate underlying neurodegenerative changes even when unaccompanied by deficits on formal testing. The cognitive complaint group may represent a pre-mild cognitive impairment stage and may provide an earlier therapeutic opportunity than mild cognitive impairment. MRI analysis approaches incorporating signal intensity may have greater sensitivity in early preclinical stages than volumetric methods.

Executive function and the frontal lobes: a meta-analytic review

Currently, there is debate among scholars regarding how to operationalize and measure executive functions. These functions generally are referred to as "supervisory" cognitive processes because they involve higher level organization and execution of complex thoughts and behavior. Although conceptualizations vary regarding what mental processes actually constitute the "executive function" construct, there has been a historical linkage of these "higher-level" processes with the frontal lobes. In fact, many investigators have used the term "frontal functions" synonymously with "executive functions" despite evidence that contradicts this synonymous usage. The current review provides a critical analysis of lesion and neuroimaging studies using three popular executive function measures (Wisconsin Card Sorting Test, Phonemic Verbal Fluency, and Stroop Color Word Interference Test) in order to examine the validity of the executive function construct in terms of its relation to activation and damage to the frontal lobes. Empirical lesion data are examined via meta-analysis procedures along with formula derivatives. Results reveal mixed evidence that does not support a one-to-one relationship between executive functions and frontal lobe activity. The paper concludes with a discussion of the implications of construing the validity of these neuropsychological tests in anatomical, rather than cognitive and behavioral, terms.

Wisconsin Card Sorting Test performance after putaminal hemorrhagic stroke

The purpose of this study was to compare the performance differences in the Wisconsin Card Sorting Test (WCST) between 55 patients with putaminal hemorrhage (PH) 3 months after stroke and 69 age-matched normal controls. Impairment on WCST was defined as performance greater than 1.64 standard deviation below the control mean. A multivariate analysis of covariance (MANCOVA) controlling for education yielded a significant main effect for group but not for education and interaction of group x education. Univariate analyses revealed significant between-group differences in five WCST measures, including perseverative errors (PE), perseverative responses (PR), conceptual-level responses (CLR), number of categories completed (NCC), and trials to complete the first category (TCC). For patients with PH, z-scores for two WCST indices were within the impaired range: TCC and PR. A high percentage of patients (40-47%) scored in the designated impaired range on NCC, PR, PE, and TCC. The WCST variables discriminated patients from controls with an overall accurate classification rate of 91.9%. Of these, the variables that contributed most to the differentiation between patients and normal controls were PE, CLR, and total number correct (TNC) (a standardized canonical discriminant function coefficient > 0.40). Finally, no significant hemispheric laterality effects emerged on any of the WCST variables. The results of this study provide further evidence of impaired mental set shifting in stroke patients with PH. The implications for rehabilitation professionals are discussed, and recommendations for further research are made.

Effect of temporary clipping on frontal lobe functions in patients with ruptured aneurysm of the anterior communicating artery

BACKGROUND

After surgery for ruptured anterior communicating artery (ACoA) aneurysm, several patients who have achieved a favorable neurological outcome yet have been observed to suffer from a poor cognitive outcome. The aim of this study was to explore the possible effects of temporary clip applications on frontal lobe functions in the patients with ruptured ACoA aneurysm.

METHODS

Forty patients were chosen among a series of cases who underwent an early surgery (within 96 h) after ACoA aneurysm bleeding. All of them were in Hunt-Hess grade 1 or grade 2. Of the 40 patients, temporary clipping was used in 22 patients (group A), whereas it was not used in 18 patients (group B). These two groups were compared with 20 volunteers (group C) without neurologic or psychiatric disorders.

RESULTS

The mean duration of temporary vessel occlusion for both A1 was 8.2 +/- 2.9 min (4-15) in group A. Neither clinical nor radiographic strokes were detected. An improvement in frontal lobe function occurred at long term in group B patients. Whereas, cognitive deficits were persisting at long-term follow-up in group A, especially in patients who had temporary clipping duration longer than 9 min.

CONCLUSIONS

The results emphasize that the negative effects of temporary vessel occlusion on cognitive changes occur before ischemic damage. Thus, such negative effects of temporary clipping on cognitive functions should not be neglected by surgeons during surgery.

Cognition in schizophrenia: impairments, determinants, and functional importance

Recent findings support and add to earlier findings of cognitive dysfunction in schizophrenia. Deficits across neurocognitive domains such as attention, working memory, language skills, and executive functioning tend to be moderate, with the most pronounced deficits found in verbal learning and memory. All these neurocognitive domains are related to adaptive and social skills, with executive functions and verbal learning and memory showing more variance across more domains than other neuro-cognitive variables. Negative symptoms and neurocognitive domains, although correlated, are distinct and have differential pathways of change with treatment. General psychopathology symptoms, such as depression and anxiety, may become important treatment targets as strategies are developed for translating cognitive enhancement to real-world functional performance.

Measuring executive dysfunction in an acute rehabilitation setting: using the dysexecutive questionnaire (DEX)

It is recognized that existing neuropsychological measures of executive dysfunction lack adequate sensitivity and selectivity. While attempts have been made to develop improved measures, these have not yet been of great value to those who need to accurately identify executive deficits in a clinical setting. Several behavioral rating scales have been developed for this reason, including the 20-item Dysexecutive Questionnaire (DEX), which forms part of the Behavioral Assessment of the Dysexecutive Syndrome (BADS) test battery. To investigate the ability of the DEX to identify executive dysfunction in an acute rehabilitation setting, the BADS was administered to 64 persons who had sustained traumatic brain injury. It was found to be almost as sensitive to executive dysfunction, as measured by the total score obtained on the BADS battery, as an extended 65-item version of the scale, when completed by either the occupational therapist or clinical neuropsychologist working with each patient. Family members and the patient themselves provided, as expected, less accurate information. Our results indicate that the DEX can be used with some confidence as a screening instrument to identify executive dysfunction in an acute rehabilitation setting, provided it is completed by professional personnel, trained to be sensitive to the cognitive and behavioral concomitants of this disorder.

A meta-analytic review of verbal fluency performance following focal cortical lesions

A meta-analysis of 31 studies with 1,791 participants was conducted to investigate the sensitivity of tests of verbal fluency to the presence of focal cortical lesions. Relative to healthy controls, participants with focal frontal injuries had large and comparable deficits on phonemic (r = .52) and semantic (r = .54) fluency. For frontal but not nonfrontal patients, phonemic fluency deficits qualified as differential deficits when compared with IQ and psychomotor speed; phonemic fluency was also more strongly and more specifically related to the presence of frontal lesions than the Wisconsin Card Sorting Test scores. In contrast, temporal damage was associated with a lesser deficit on phonemic fluency (r = .44) but a larger deficit on semantic fluency (r = .61).

Executive Functioning and Memory for the Rey-Osterreith Complex Figure Task Among Community Adolescents

Although there is empirical support for the link between executive functioning (EF) and visual memory among adults, there has been less exploration of this link among children, especially adolescents. We examined the relation between several EF measures and performance on the Rey-Osterrieth Complex Figure (RCF) in a sample of 160 community adolescents. Each was administered the Wisconsin Card Sorting Test (WCST), Conners Continuous Performance Test (CPT), and the RCF, scored using Bernstein and Waber's (1996) Developmental Scoring System (DSS). Ability to organize the RCF related to memory encoding/retrieval, but not to long-term storage. Indexes derived from the WCST and CPT failed to correlate with any RCF index, raising questions about the relation between DSS scores and EF. Even so, data supported the convergent validity of the DSS system as a reflection of visual-constructional ability and provided evidence of the importance of organizational strategies to visual memory among adolescents.

The impact of frontal and non-frontal brain tumor lesions on Wisconsin Card Sorting Test performance

Several lesion and imaging studies have suggested that the Wisconsin Card Sorting Test (WCST) is a measure of executive dysfunction. However, some studies have reported that this measure has poor anatomical specificity because patients with either frontal or non-frontal focal lesions exhibit similar performance. This study examined 25 frontal, 20 non-frontal low-grade brain tumor patients, and 63 normal controls (NC) on the WCST. The frontal patients were also assigned to either a left frontal (n=10) group or a right frontal group (n=15) and compared with the non-frontal group and NC. It was hypothesized that the frontal brain tumor patients would display greater deficits on categories achieved and a higher number of perseverative errors than non-frontal brain tumor patients on the WCST. Finally, it was predicted that right frontal brain tumors would result in greater executive functioning deficits than left frontal or non-frontal brain tumors. Results indicated that the left frontal group achieved the fewest categories and committed the most perseverative errors compared to the other patient and normal control groups. In addition, the left frontal group committed significantly more perseverative errors than the right frontal group. These results suggest that the WCST is sensitive to the effects of low-grade brain tumors on executive functioning.

Induced oscillations and the distributed cortical sources during the Wisconsin card sorting test performance in schizophrenic patients: new clues to neural connectivity

Prefrontal dysfunction has been associated with schizophrenia. Activation during Wisconsin card sorting test (WCST) is a common approach used in functional neuroimaging to address this failure. Equally, current knowledge states that oscillations are basic forms of cells-assembly communications during mental activity. Promising results were revealed in a previous study assessing healthy subjects, WCST and oscillations. However, those previous studies failed to meet the functional integration of the network during the WCST in schizophrenics, based on the induced oscillations and their distributed cortical sources. In this research, we utilized the brain electrical tomography (variable-resolution brain electromagnetic tomography) technique to accomplish this goal. Task specific delta, theta, alpha and beta-2 oscillations were induced and simultaneously synchronized over large extensions of cortex, encompassing prefrontal, temporal and posterior regions as in healthy subjects. Every frequency had a well-defined network involving a variable number of areas and sharing some of them. Oscillations at 11.5, 5.0 and 30 Hz seem to reflect an abnormal increase or decrease, being located at supplementary motor area (SMA), left occipitotemporal region (OT), and right frontotemporal subregions (RFT), respectively. Three cortical areas appeared to be critical, that may lead to difficulties either in coordinating/sequencing the input/output of the prefrontal networks-SMA, and retention of information in memory-RFT, both preceded or paralleled by a deficient visual information processing-OT.

Is the Anterior Attentional System as Complex as the Posterior Attentional System?

Abstract: The objectives of this review paper were to demonstrate whether there are separable attentional processes related to the frontal lobes, and to illustrate procedures on how to examine this question. Distinctions among frontal lobe attentional processes can be achieved if cognitive processes are adequately differentiated and if a sufficient number of patients are assessed to allow investigation of the relation of these distinct processes to different frontal lobe regions. The first section summarizes early evidence for the fractionation of the anterior attentional system using clinical tests. The second section extends these findings using experimental tests such as feature integration reaction time tasks. Different attentional processes include activation, task setting, shifting, and differentiating among relevant and irrelevant information. Although there are multiple anterior attentional processes related to different frontal brain regions, such anterior attentional processes likely interact with posterior attentional processes, with task demands altering the relationship among brain regions involved.

Factors Affecting the Short-Term Prognosis of Alcohol Dependent Patients Undergoing Inpatient Detoxification

Stable measures of psychological functioning require a considerable period of abstinence. However, the duration of inpatient detoxification programs has decreased dramatically in most health care systems, posing a novel challenge for clinical evaluation of patients. The present study was carried out to examine whether factors predicting short-term prognosis can be identified in alcohol dependent subjects during early stages of inpatient detoxification. Self-reports of mood states were obtained, and executive cognitive functioning was examined. Outcome was studied at 2-3 months. No correlation was found between self-reported symptoms of depression, hopelessness, and anxiety, and percentage of nondrinking days. A significant positive correlation was found between Wisconsin Card Sorting Test (WCST) performance and short-term prognosis measured by this parameter. Thus, in addition to transient withdrawal-related effects, impairments of WCST performance in early stages of alcohol detoxification may reflect more long standing deficits in problem-solving strategies, of possible relevance for matching patients to treatment services.

Wisconsin Card Sorting Test performance in patients with focal frontal and posterior brain damage: effects of lesion location and test structure on separable cognitive processes

Forty-six patients with single focal lesions (35 frontal, 11 nonfrontal) were administered the Wisconsin Card Sorting Test (WCST) under three conditions of test administration. The three conditions varied in the amount of external support provided via specificity of instructions. The WCST, while a multifactorial test, is specifically sensitive to the effects of frontal lobe damage if deficits in language comprehension and visual-spatial search are controlled. There is also specificity of functioning within the frontal lobes: patients with inferior medial frontal lesions, unilateral or bilateral, were not impaired on the standard measures although they had increased loss of set when informed of the sorting categories. Verbal instructions may provide a probe to improve diagnosis and prognosis, assessment of the potential efficacy of treatment, and the time frame of plasticity of specific cognitive operations.

Change of perspective in discourse comprehension: encoding and retrieval processes after brain injury

Damage to frontal areas has been associated with nonaphasic language disturbances in which word and sentence level processes remain largely intact but text level processes are impaired. Most studies providing evidence for these language deficits have concentrated on text production. To study text comprehension of nonaphasic patients, we adopted the paradigm of Anderson and Pichert (1978) that was developed to separate encoding from retrieval processes. Subjects read a story under one of two alternative perspectives and subsequently recalled it. After this first recall, they were instructed to now adopt the second perspective and to recall the story once more. Twenty-four brain-injured patients participated. Each patient's lesion was evaluated with respect to the involvement of right- and/or left-frontal regions. Seven patients showed unilateral left-frontal lesions, five patients unilateral right-frontal lesions, four patients had bilateral frontal damage, and the lesions of the remaining eight patients did not involve frontal areas. The only factor predicting behavioral results was the presence of a left-frontal lesion. For patients without frontal lesions and patients with unilateral right-frontal lesions, we replicated previously reported results. Encoding relevant information was recalled better than other information. Furthermore, the switch of perspective aided recall of perspective relevant information during the second recall. In contrast, patients with left-frontal or bilateral frontal lesions could not make use of the perspective instructions. While they showed comparable recall performance, as well as sensitivity to the relative ease of information, neither the encoding instructions nor the switch instructions had an impact on the recall patterns. These results suggest that left-frontal damage leads to an impairment of goal directed text processing skills.

Cognitive deficits in schizophrenia on the WAIS-R NI Sentence Arrangement Subtest. Wechsler Adult Intelligence Scale-Revised Neuropsychological Inventory

Performance of participants diagnosed with schizophrenia on the Sentence Arrangement subtest of the WAIS-R NI and several tests sensitive to frontal lobe dysfunction was significantly poorer than that of manic depressive or control participants. Several measures of performance of patients diagnosed with schizophrenia on the WAIS-R NI Sentence Arrangement subtest appeared to support recent interpretations of the cognitive deficit seen in schizophrenia. These data represent the first demonstration of deficit performance by patients with schizophrenia on the Sentence Arrangement subtest. This is also supportive of the prediction that one of the areas whose activity may influence scores on this subtest is the prefrontal cortex. In addition, neither positive nor negative symptoms systematically correlated with the cognitive deficits reported despite specific predictions from the current literature.

The influence of prolactin response to d-fenfluramine on executive functioning in major depression

BACKGROUND

The main purpose of this study was to assess the influence of serotonergic activity, as measured by prolactin response to d-fenfluramine, on executive functioning in major depression.

METHODS

Forty-one persons between 22 and 71 years of age who met the DSM-IV criteria for major depressive episode were administered the Wisconsin Card Sorting Test (WCST) in computerized format, and d-fenfluramine was administered orally. Postfenfluramine blood samples for ascertaining plasma prolactin levels were obtained.

RESULTS

The key finding was that prolactin response was positively related to four out of five selected WCST variables. Also, increasing age was associated with decreasing WCST performance. There was no interaction between prolactin response and age, indicating that the effects of prolactin response on the WCST generalized across the age range examined.

CONCLUSIONS

The overall pattern of results suggests that there may be a relationship between serotonergic activity and executive functioning in major depression.

What are we changing with neurocognitive rehabilitation? Illustrations from two single cases of changes in neuropsychological performance and brain systems as measured by SPECT

If cognitive remediation is to be developed further, there have to be not only large-scale randomized trials but also detailed analysis of the strategies used to produce improved performance. In this study the strategies adopted by two people who took part in a remediation program are investigated, with their results on neuropsychological tasks and with concomitant brain image data gathered via SPECT while the participant was performing a Verbal Fluency task. After remediation there were improvements in many of the neuropsychological tests, and changes in the scan data. The changes in strategies and brain activation were different for both individuals. One person increased his verbal output but without close monitoring, so also increased his errors. The other participant decreased his output but monitored it more closely, and so decreased the errors. These strategies were reflected in the changes in activation between scans, i.e. increases in temporal areas for the increased output and bilateral decreases in the anterior cingulate and left pre-motor areas for the decreased output case. Together these results imply that the participants continue to use individual strategies which for many of the neuropsychological tasks produced gains. Further investigation of whether it is possible to change idiosyncratic strategy use is needed if we are to develop the efficacy of this remediation technique.

High-energy phosphates in the frontal lobe correlate with Wisconsin Card Sort Test performance in controls, not in schizophrenics: a 31phosphorus magnetic resonance spectroscopic and neuropsychological investigation

In recent years, a number of 31phosphorus magnetic resonance spectroscopy (P-MRS) studies on the frontal lobe of schizophrenics have been performed, reporting alterations of phospholipids and high-energy phosphates. Deicken et al. (1994b) recently found positive correlations between left frontal phosphomonoester% (PME%) levels and the performance of a specific frontal lobe task, the Wisconsin Card Sorting Test (WCST), in schizophrenics. In the present paper, the correlations between phospholipids and high-energy phosphates in the frontal lobe of 26 schizophrenics and 23 controls measured with a volume-selective P-MRS method were investigated. Overall, we could not find any correlations between WCST results and phospholipid levels, but in controls phosphocreatine% (PCr%) and PCr/adenenosine triphosphate (ATP) ratios were negatively correlated with test performance. Since PCr behaves as a buffer of ATP, in the sense that when ATP is consumed by neuronal activity PCr is catalysed rapidly to ATP, increased PCr% values and, moreover, increased PCr/ATP ratios point to a decreased ATP consumption. Thus, the correlations found between PCr% and PCr/ATP and test performance in controls point to an association between reduced performance in a specific frontal lobe task and decreased energy demanding processes at rest. This association was not found in schizophrenics, possibly due to the influence of neuroleptic medication or the disease process per se.

Wisconsin Card Sorting Test dimensions in schizophrenia: factorial, predictive, and divergent validity

This study explored the factor structure of the Wisconsin Card Sorting Test (WCST). Scores from 197 participants with schizophrenia or schizoaffective disorder were subjected to an exploratory factor analysis that yielded three factors: Perseveration, Nonperseverative Error, and Inefficient Sorting. Comparison with two previous factor analyses revealed remarkable factorial invariance. Correlations with subject and illness characteristics, symptom dimensions, and work performance demonstrated predictive and divergent validity for the three factors. However, a representative item from each factor yielded similar correlations with very little loss of power suggesting that the factors are composed of highly redundant items. When data reduction is necessary, schizophrenia researchers are justified in using three variables: perseverative error, nonperseverative error, and failure to maintain set, to represent WCST performance.

Brain activation during cognitive stimulation with the Wisconsin Card Sorting Test--a functional MRI study on healthy volunteers and schizophrenics

It has been demonstrated by single photon emission computed tomography (SPECT) and positron emission tomography (PET) that frontal brain regions are stimulated during performance of the Wisconsin Card Sorting Test (WCST). The WCST is also regarded as one of the standard tests for the assessment of frontal activity in brain imaging studies of schizophrenia. In this study cerebral activation was assessed by means of functional magnetic resonance imaging (fMRI). In healthy volunteers WCST stimulation resulted in a right lateralized frontal activation. In 13 chronic schizophrenics on stable neuroleptic medication, a lack of activation in the right prefrontal cortex and--as a trend--an increased left temporal activity during execution of the WCST was noted compared to controls. Since a one-slice technique was used, no information about the activation pattern in adjacent brain regions was obtained. However, as fMRI possesses a superior spatial resolution compared to SPECT and PET, the anatomical localization of the activation effect in the measured slice can be defined more precisely. Beside these methodological considerations, the results are discussed in relation to prior findings of a reduced ability of schizophrenics to coordinate cerebral function.