Wisconsin Card Sorting Test Measures Research Articles

A network analysis and empirical validation of executive deficits in patients with psychosis and their healthy siblings

BackgroundPsychopathological symptoms and cognitive impairment are core features of patients with psychotic disorders. Executive dysfunctions are commonly observed and typically assessed using tests like the Wisconsin Card Sorting Test (WCST). However, the structure of executive deficits remains unclear, and the underlying processes may be different.This study aimed to explore and compare the network structure of WCST measures in patients with psychosis and their unaffected siblings and to empirically validate the resulting network structure of the patients. MethodsThe subjects were 298 patients with a DSM 5 diagnosis of a psychotic disorder and 89 of their healthy siblings. The dimensionality and network structure of the WCST were examined by means of exploratory graph analysis (EGA) and network centrality parameters. ResultsThe WCST network structure comprised 4 dimensions: perseveration (PER), inefficient sorting (IS), failure to maintain set (FMS) and learning (LNG). The patient and sibling groups showed a similar network structure, which was reliably estimated. PER and IS showed common and strong associations with antecedent, concurrent and outcome validators. The LNG dimension was also moderately associated with these validators, but FMS did not show significant associations. ConclusionsFour cognitive processes underlying WCST performance were identified by the network analysis. PER, IS and LNG were associated with and shared common antecedent, concurrent and outcome validators, while FMS was not associated with external validators. These four underlying dysfunctions might help disentangle the neurofunctional basis of executive deficits in psychosis.

A network analysis of executive deficits in patients with psychosis and their healthy siblings

IntroductionPsychopathological symptoms and cognitive impairment are core features of patients with psychotic disorders. Executive dysfunctions are within the most commonly observed deficits and the Wisconsin Card Sorting Test (WCST) is the test most extensively used for their assessment. Yet, the structure of executive deficits remains unclear, as there may be different underlying processes.ObjectivesThe study’s aims were to explore and compare the network structure of the WCST measures in psychosis and their unaffected siblings.MethodsSubjects were 298 patients with a DSM 5 diagnosis of psychotic disorder and 89 of their healthy siblings. The dimensionality and network structure of the 13 WCST measures were examined by means of the Exploratory Graph Analysis (EGA) and centrality parameters.ResultsThe WCST network structure comprised 4 dimensions: Perseveration (PER), Inefficient sorting (IS), Failure to maintain set (FMS) and Learning (LNG). Patient and sibling groups showed a similar network structure and in both cases the network structure was reliably estimated.ConclusionsPerseveration measures reflect the inability to switch sorting rules when necessary. Scores for the IS dimension can occur when the subject ineffectively tries to test different sorting hypotheses, changing at random the response. FMS reflects the subject’s strategy when he/she is able to find out the sorting rule, but is unable to keep applying that rule long enough. LNG comprised conceptual ability and learning items. The lack of significant difference between network structures is in keeping with results from exploratory and confirmatory studies demonstrating an invariant cognitive factor structure between schizophrenia patients and their unaffected siblings.

Longitudinal Analysis of Particulate Air Pollutants and Executive Function in Southern California Youth

Executive function (EF) is critical for social well-being and mental/physical health. Previous studies on ambient air pollution and EF have produced mixed results, and the suggested adverse effect was largely inferred from studies only measuring sub-domains of EF in school-age children with limited follow-up. We conducted a prospective study to examine whether residential ambient air pollution affects EF from late childhood to early adulthood in urban-dwelling populations. A multi-ethnic cohort of Southern California twins/triplets (N=829) was examined in 2000-2014 (aged 9-21 years), each with repeated EF assessments of Preservative Responses (cognitive flexibility) and Nonperseverative Errors (control of attention resources and self-monitoring) from the Wisconsin Card Sorting Test (WCST), an integrated testing battery for frontal lobe damage. We estimated ozone and PM2.5 using generalized additive models, NOx/NO2 using land use regression models, freeway and non-freeway NOx/NO2 using CALINE4 dispersion models, and elemental carbon using the UCD/CIT chemical transport model. Monthly exposure time-series were aggregated to derive 1-, 2-, and 3-year averages preceding each EF assessment. Multilevel mixed-effects models were used to estimate the exposure effects on continuous standard scores of EF. Long-term PM2.5 (range of IQRs: 4.86-5.25 μg/m3) was significantly (all p<0.05) associated with poorer performance in both WCST measures, with effect sizes equivalent to 4.5-7 years of delay in EF development, adjusting for potential confounders (sociodemographics; neighborhood quality and socioeconomic characteristics; other pollutants; spatial covariates; maternal and early-life risk factors). No consistent associations were found with other exposure measures. These results provide strong evidence that long-term PM2.5 exposure contributes to reduced EF, suggesting that the frontal lobe may represent a brain region most vulnerable to air pollution neurotoxicity.

Performance of Wisconsin Card Sorting Test in five-year-old children in Taiwan: Relationship to intelligence and cognitive development.

Objective(1) To develop the norm of Wisconsin Card Sorting Test (WCST), (2) to investigate the pathway of the indices for WCST performances and (3) the association between WCST, intelligence quotient (IQ), and parent-report measures of children’s development in typically developing five-year-olds in the community.MethodFifty-three children were recruited from community health centers. The WCST, Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), and Taiwan Birth Cohort Study- Developmental Instrument (TBCS-DI) was used to measure children's executive function, IQ and parent report of children's development respectively.ResultsMean categories achieved (CA) was 2.02 (standard deviation [SD] = 1.41), and percent conceptual level response (PCLR) was 29.85(SD = 18.36) in five year-olds. The WCST indices showed a pathway relationship of PCLR being negatively associated with perseverative error (PE), and PE and non- perseverative error being negatively associated with CA. Association among the PCLR index of the WCST, cognitive domain of the TBCS-DI, and performance IQ and verbal IQ of the WPPSI-R was found.ConclusionRegular improvement with age was found compared to the norm of six-year-olds in a previous study of children from the same region. The number sorting criteria was more difficult thus they continued to perform persistent errors of color or form when sorting. Association was found among the professional administered IQ, computerized WCST, and a parent report developmental instrument. Showing parent report is an accurate reflection of children's cognitive development at this age.

Measuring learning potential in people with schizophrenia: A comparison of two tasks

Learning potential measures utilize dynamic assessment methods to capture performance changes following training on a cognitive task. Learning potential has been explored in schizophrenia research as a predictor of functional outcome and there have been calls for psychometric development in this area. Because the majority of learning potential studies have utilized the Wisconsin Card Sorting Test (WCST), we extended this work using a novel measure, the Rey Osterrieth Complex Figure Test (ROCFT). This study had the following aims: 1) to examine relationships among different learning potential indices for two dynamic assessment tasks, 2) to examine the association between WCST and ROCFT learning potential measures, and 3) to address concurrent validity with a performance-based measure of functioning (Test of Grocery Shopping Skills; TOGSS). Eighty-one adults with schizophrenia or schizoaffective disorder completed WCST and ROCFT learning measures and the TOGSS. Results indicated the various learning potential computational indices are intercorrelated and, similar to other studies, we found support for regression residuals and post-test scores as optimal indices. Further, we found modest relationships between the two learning potential measures and the TOGSS. These findings suggest learning potential includes both general and task-specific constructs but future research is needed to further explore this question.

Impact of pain on cognitive functions in primary Sjögren syndrome with small fiber neuropathy: 10 cases and a literature review.

Primary Sjögren syndrome (pSS) is a chronic systemic autoimmune disease characterized by xerophthalmia, xerostomia, and potential peripheral or central neurological involvement. In pSS, the prevalence of cognitive disorders is generally sparse across literature and the impact of pain on cognitive profile is unclear. The aim of this study was to determine the relation between pain, cognitive complaint, and impairment in a very homogenous population of 10 pSS patients with painful small fiber neuropathy (PSFN) and spontaneous cognitive complaint. Neurological exam, neuropsychological assessment, clinical evaluation measuring pain level, fatigue, anxiety, depression, and cognitive complaint were performed. Our results showed that 100% of patients had cognitive dysfunction especially in executive domain (80%). The most sensitive test was the Wisconsin Card Sorting Test (WCST), abnormal in 70% of our population. Moreover, we found clear cut significant correlations between pain levels and 3 measures of WCST: the number of errors (R = –0.768, P = .0062), perseverations (R = 0.831, P = .0042), and categories (R = 0.705, P = .02). In the literature review, the impact of pain is underexplored and results could be discordant. In a homogeneous cohort of pSS patients with PSFN, a cognitive complaint seems to be a valid reflection of cognitive dysfunction marked by a specific executive profile found with the WCST. In this preliminary study, this profile is linked to the level of pain and highlights that an appropriate management of pain control and a cognitive readaptation in patients could improve the quality of life.

Wisconsin Card Sorting Test performance impairment in schizophrenia: An Indian study report.

Aim:The present study attempted to find out the relationship between positive and negative clinical symptoms and Wisconsin Card Sorting Test (WCST) performance in a group of schizophrenia patients.Methodology:Fifty schizophrenia patients were assessed using the Positive and Negative Syndrome Scale (PANSS) by a trained psychiatrist (TKA) and two groups, each of 25 positive symptom and 25 negative symptom schizophrenia patients were formed. On these fifty patients with schizophrenia and 15 normal control groups, WCST measures were applied by a clinical psychologist (SS) who remained blind to the PANSS score.Results:Schizophrenia diagnosis significantly affects WCST performances. One-way analysis of variance (ANOVA) revealed schizophrenia patients showed a significant impairment on all WCST indices compared with normal subjects except versus total number of correct responses. Post hoc comparison (Tukey HSD Test) between means revealed that negative schizophrenia patients showed significantly worse performance on most WCST performance parameters: percent errors, perseverative responses, percent perseverative responses, perseverative errors, percent perseverative errors, and conceptual level responses.Conclusions:Both positive and negative symptom schizophrenia patients have some distinct WCST measures deficits.

Assessment of executive functions in bipolar depression

Introduction Cognitive functions in bipolar disorder have been assessed during acute mood episodes but also during remission. While other cognitive functions, such as verbal and working memory, attention, verbal fluency and psychomotor speed seem to recover after the acute episode, executive functions impairment remains also during remission; this aspect led to the assumption that executive functions may be a trait marker for bipolar disorder. Objective The purpose of this study was to assess the executive functions, such as cognitive flexibility, set shifting, problem solving and abstract thinking in bipolar depression compared to healthy subjects. Method Forty patients diagnosed with Bipolar Disorder and Major Depressive Episode according to DSM IV-TR were included into the study. Executive functions were investigated using Wisconsin Card Sorting Test (WCST). Results obtained by patients were compared with those of 30 healthy who underwent the same cognitive evaluation. Results Depressed bipolar patients scored significantly worse on the majority of WCST measures. Thus, for total trials, total errors, preservative errors and preservative responses (raw scores and percents) and failure to maintain set scores, the differences between the two groups were significant at the 1% threshold ( P =0.000). The patients and controls displayed similar behavior for total correct ( P =0.215) and conceptual levels scores ( P =0.421). Conclusions Patients with bipolar disorder show during a depressive episode difficulties in most cognitive tasks involving executive functions. Results obtained by patients at failure to maintain set score suggest frontal dysfunctions for this category of patients.

Randomized controlled trial on adjunctive cognitive remediation therapy for chronically hospitalized patients with schizophrenia.

BackgroundCognitive remediation therapy (CRT) is one of the promising new non-drug approaches to reducing cognitive deficits of patients with schizophrenia that has not yet been fully evaluated in China.AimAssess the efficacy of CRT in improving the cognitive functioning, social functioning and insight of patients with chronic schizophrenia.Methods126 clinically stable inpatients with chronic schizophrenia were randomly allocated to an intervention group (with CRT) and a treatment as usual group (TAU) (which used standard occupational and recreational therapy methods). The treatment frequency and duration were the same for the two groups: five times per week for three months. The Wisconsin Card Sorting Test (WCST) was used to evaluate before versus after changes in cognitive function, the Scale of Social Skills of chronic schizophrenia Inpatients (SSSI) was used to assess social functioning, and the Insight and Treatment Attitude Questionnaire (ITAQ) was use to assess insight.ResultsFour patients dropped out during the study leaving 60 in the CRT group and 62 in the TAU group in the final analysis. Both groups showed significant improvement in WCST measures over the three-month trial but the improvement in the CRT group was significantly greater than that for the TAU group on all of the WCST measures assessed. The total SSSI score improved significantly in both groups over the three months, but the improvement in the two groups was not significantly different. The total ITAQ score also showed significant improvement in both groups over the three months and the degree of improvement was significantly greater in the CRT group than in the TAU group.ConclusionAs an adjunctive treatment to antipsychotic medication, a three month course of CRT is more effective at improving the cognitive functioning and insight of hospitalized patients with chronic schizophrenia than routine occupational and recreational therapy.

Wisconsin Card Sorting Test performance in children with developmental coordination disorder

The primary purpose of this study was to investigate and compare the executive functions measured by the Wisconsin Card Sorting Test (WCST) between children with developmental coordination disorder (DCD) and age-matched normal controls. A second purpose was to examine the relations between executive functions and school functions in DCD children. Seventy-one children with DCD and 70 children without motor problems were recruited from 14 public schools. Executive functions and school functions were assessed using the WCST, and the School Function Assessment – Chinese Version (SFA-C) respectively. Univariate analyses demonstrated significant between-group differences in five WCST measures. The logistic regression analysis showed differences between two groups on eight SFA-C subscales, and significant correlation between items measured on WCST and SFA-C was also found. The result of the study provides further evidence of impaired sub-domains of executive functions (i.e., mental shifting, flexibility) in children with DCD. The finding also adds to recent investigations into the relationship between executive functions and school functions in DCD. Implications for rehabilitation professionals and recommendations for further research are discussed.

P03-71 - Decision making, working memory and executive functions in schizophrenic patients

IntroductionSchizophrenia is a disorder related with decline in cognitive functioning. Deficit of working memory and executive functions in schizophrenia is consistently reported. On the other hand, studies of decision making in schizophrenia bring contradictory results.AimsThe aim of the study was to assess decision making and executive functions in clinically stable schizophrenic patients.MethodsThe study included 25 clinically stable schizophrenic patients (7 female, 18 male), aged 31±6 years and 25 age, sex and education years matched healthy controls. Decision making was assessed with Iowa Gambling Task (IGT). Working memory and executive functions were assessed with Wisconsin Card Sorting Test (WCST) and Trail Making Test (TMT). Psychometric asessment was provided with Positive and Negative Symptoms Scale (PANSS)ResultsNo significant differences in performance on IGT between schizophrenic patients and healthy subjects were found. Schizophrenic patients made more perseverative (t=-4,05; 0,00) and nonperseverative errors (t=-4,35, p=0,002), gave less conceptual level responses (t=-5,35; p=0,00), completed less categories (t=-4,73, p=0,00) and used more cards to complete first category (t=-3,98, p=0,00) in WCST. They also needed more time to complete part A (t=-5,62; p=0,00) and B (t=-4,06; p=0,00) of TMT test.ConclusionsNo significant differences in performance on IGT between schizophrenic patients and healthy subjects were found. On the other hand, schizophrenic patients performed significantly worse on all measures of WCST as well as in TMT test.

Wisconsin Card Sorting Test performance and impulsivity in patients with temporal lobe epilepsy: Suicidal risk and suicide attempts

Objective: The goal of the study described here was to determine if executive dysfunction and impulsivity are related to risk for suicide and suicide attempts in patients with temporal lobe epilepsy. Method: Forty-two patients with temporal lobe epilepsy were recruited. A detailed medical history, neurological examination, serial EEGs, Mini-International Neuropsychiatric Interview, executive function, and MRI were assessed. Multiple regression analysis was carried out to examine predictive associations between clinical variables and Wisconsin Card Sorting Test measures. Results: Patients’ scores on the Risk for Suicide Scale ( n = 24) were greater than 7, which means they had the highest relative risk for suicide attempts. Family history of psychiatric disease, current major depressive episode, left temporal lobe epilepsy, and perseverative responses and total errors on the Wisconsin Card Sorting Test increased by 6.3 and 7.5 suicide risk and suicide attempts, respectively. Executive dysfunction (specifically perseverative responses and more total errors) contributed greatly to suicide risk. Conclusion: Executive performance has a major impact on suicide risk and suicide attempts in patients with temporal lobe epilepsy.

P01-194 Decision making, working memory and executive functions in euthymic bipolar patients

Aims:Decision making, as well as working memory and executive functions are among the most significant cognitive processes, associated with prefrontal cortex function. Decision making is associated with the orbitofrontal cortex function. Working memory and executive functions are dependent on the dorsolateral prefrontal cortex. Orbitofrontal, as well as dorsolateral prefrontal cortex dysfunction in bipolar disorder has been reported. The aim of the study was to assess decision making and executive functions in euthymic bipolar patients.Methods:The study included 13 euthymic bipolar patients (6 female, 7 male), aged 43±11 years and 11 age, sex and education years matched healthy controls. Decision making was assessed with Iowa Gambling Task (IGT). Working memory and executive functions were assessed with Wisconsin Card Sorting Test (WCST) and Trail Making Test (TMT). Depressive and/ or manic symptoms were measured with Hamilton Depression Scale (HAM-D) and Young Mania Rating Scale (YMRS).Results:Euthymic bipolar patients made more nonperseverative errors (t=2,53, p=0,01), gave less conceptual level responses (t=-2,33, p=0,03), completed less categories (t=-1,66, p=0,005) and used more cards to complete first category (t=1,49, p=0,003) in WCST. They also gained less money in IGT (t=-1,34, p=0,03).Conclusions:Bipolar patients performed significantly worse on several measures of WCST. Euthymic bipolar patients gained less money in IGT compared to healthy controls, although no significant differences in responding style in IGT were found.

Dopamine transporter 3'UTR VNTR genotype is a marker of performance on executive function tasks in children with ADHD

BackgroundAttention-Deficit/Hyperactivity Disorder (ADHD) is a heterogeneous disorder from both clinical and pathogenic viewpoints. Executive function deficits are considered among the most important pathogenic pathways leading to ADHD and may index part of the heterogeneity in this disorder.MethodsTo investigate the relationship between the dopamine transporter gene (SLC6A3) 3'-UTR VNTR genotypes and executive function in children with ADHD, 196 children diagnosed with ADHD were sequentially recruited, genotyped, and tested using a battery of three neuropsychological tests aimed at assessing the different aspects of executive functioning.ResultsTaking into account a correction for multiple comparisons, the main finding of this study is a significant genotype effect on performances on the Tower of London (F = 6.902, p = 0.009) and on the Wechsler Intelligence Scale for Children, Third Edition (WISC-III) Freedom From Distractibility Index (F = 7.125, p = 0.008), as well as strong trends on Self Ordered Pointing Task error scores (F = 4,996 p = 0.026) and WISC-III Digit Span performance (F = 6.28, p = 0.023). Children with the 9/10 genotype exhibited, on average, a poorer performance on all four measures compared to children with the 10/10 genotype. No effect of genotype on Wisconsin Card Sorting Test measures of performance was detected.ConclusionResults are compatible with the view that SLC6A3 genotype may modulate components of executive function performance in children with ADHD.

Wisconsin Card Sorting Test performance in bipolar disorder: effects of mood state and early course

Patients experiencing an acute mood episode of bipolar disorder are impaired on cognitive tests of executive functioning when compared with healthy subjects. However, it is unclear to what extent executive dysfunction exists (i) during syndromal remission, when mood symptoms are attenuated, and (ii) during the early course of bipolar disorder. To clarify these issues, we examined retrospective data on a standard clinical version of the Wisconsin Card Sorting Test (WCST) administered to 25 euthymic, 21 first-episode manic or mixed, and 34 multiple-episode manic or mixed patients with bipolar I disorder, and 48 healthy comparison subjects. These groups were compared on five WCST measures of executive ability. On all but one measure the healthy group's performance was superior to that of both first- and multiple-episode groups. The euthymic group outperformed the multiple-episode group, but performed similarly to the first-episode group on all but one measure. The healthy and euthymic groups did not differ significantly on any measure. Effect sizes ranged from small to moderate. Executive dysfunction may be a mediating vulnerability indicator of bipolar disorder that is strongly related to mood state, but only modestly related to chronicity of illness during the early disease course.

EXECUTIVE DYSFUNCTION SCREENING TEST FOR NEUROPSYCHIATRIC DISORDERS

The Analogies Understanding Test (AUT) was developed as a brief cognitive screening task of executive problem solving. A few of the test items at the beginning are “facilitated” as a means of engaging patients. Individuals with schizophrenia and mild Alzheimer's Disease (AD) made significantly less correct responses than their control groups. The schizophrenia patients, but not AD patients, made significantly more perseverations than controls on the AUT. As expected, AUT performance in schizophrenia patients correlated with the Wisconsin Card Sorting test measures. Preliminary findings suggest that the AUT test may be useful as a measure of executive dysfunction in neuropsychiatric patients.

Stereotypy in schizophrenia

Objectives In schizophrenia, stereotypy is observed, a symptom characterized by repetitive, functionless motor behaviour. Whereas cognitive dysfunctioning is known to remain stable throughout the illness, less is known about the course of the motor symptoms. The Zeigeversuch [Mittenecker, E., 1953. Perseveration und Persönlichkeit: 1. Teil: experimentelle Untersuchungen. Z. Exp. Angew. Psychol. 1, 5–31], which entails the generation of a random sequence of button presses, was claimed to capture stereotypy. We used a newly designed computerized version of the Zeigeversuch, the Stereotypy Test Apparatus (STA) to evaluate the evolution of STA performance through the course of the illness. Methods To assess stereotyped and perseverative behaviour, 58 schizophrenic inpatients and 48 healthy controls performed the STA and the Wisconsin Card Sorting Test (WCST), respectively, as well as several other traditional neuropsychological tests and the Symbol Digit Substitution Test (SDST) on a writing digitizer. Results The STA correlated only weakly with the WCST and SDST measures but not with the cognitive or motor slowing on the SDST, nor with the other cognitive measures. Stereotyped and perseverative idiosyncrasies both seem to increase in the course of the illness, in contrast with other cognitive dysfunctions. However, whereas perseveration is already present in the early stages of the illness, stereotyped behaviour only manifests itself in the later stages of schizophrenia. Failure of cognitive inhibition may result in an activation of prepotent stereotyped responses captured by the STA.

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.

The influence of acculturation on the Wisconsin Card Sorting Test by Mexican Americans

This study examined the speculation that the Wisconsin Card Sorting Test (WCST) might be a relatively culture-free neuropsychological test. The relationship between level of acculturation and performance on the Spanish version of the WCST was investigated, using a sample of Mexican American adults ( N = 52). When the sample was divided into two groups based on level of acculturation as measured by the Acculturation Rating Scale for Mexican Americans—2nd Edition, within-group contrasts demonstrated that higher levels of acculturation significantly improved performance on the WCST. The performance of this sample was compared to select Spanish norms, finding no clinically significant differences. Contrasts with English norms for the WCST yielded significant differences on a majority of the WCST measures, demonstrating that the English norms are inappropriate for use with this population. This study concludes that the WCST is not a culture-free neuropsychological test.

Updating Information in Verbal Working Memory and Executive Functioning

50 older adults (M age=77.9 yr., SD=7.3; 35 women and 15 men) were tested using the updating working-memory task. They were also given the neuropsychological Wisconsin Card Sorting Test, assumed to evaluate executive functioning and the frontal cortex. A factor analysis with age, education, and verbal ability partialled out was computed on the updating task outcomes and resulted in a two-factor solution, indicating that this task requires two independent processes, interpreted as reflecting a storage component and an updating component. Partial correlations with age, education, and verbal ability partialled out indicated that Wisconsin Card Sorting Test measures were significantly associated with the factor supposed to reflect the updating process. Such results appeared consistent with the model of working memory with a central executive system involved in the updating process and related to the executive-frontal functioning, and a phonological loop system involved in the storage of verbal information and not linked to executive-frontal functions.