A comparison of remediation techniques on the Wisconsin Card Sorting Test in schizophrenia

A wealth of evidence has revealed that deficits on a commonly used measure of executive-function, the Wisconsin Card Sorting Test (WCST), can be improved through a variety of methods of instruction in patients with schizophrenia. Relatively little is known however, which of these remediation methods produce strongest and most durable effects and whether these effects generalize to other, untrained executive-function measures. Two of the most commonly studied methods for remediation on the WCST, step-by-step didactic instruction on the task and utilization of self-monitoring strategies, have both been shown to improve WCST performance, yet have never been directly compared. Thirty-four participants with schizophrenia were randomly assigned to one of three experimental conditions: Condition A consisted of didactic training which incorporated a detailed account of changing sorting principles throughout the test; Condition B consisted of a self-monitoring strategy that required that participants verbalize their strategies out loud after each card sort; Condition C was a non-trained control group that received the same outcome assessments as the two training groups at identical time intervals without intervening training. Patients were assessed with the WCST and two other executive-function tests immediately prior to training, immediately after training and at a 1-month follow-up. Results revealed: (1) participants assigned to the didactic and self-monitoring conditions made significant gains on the WCST relative to a no-intervention control condition; (2) the effects of self-monitoring, but not didactic training, were evident at a one-month follow-up; and (3) only participants assigned to the self-monitoring condition showed generalization to a second, non-trained measure of executive-function. The significance of these results for implementation of strategies for comprehensive and sustained programs of remediation are discussed.     

Wisconsin Card Sorting Test performance in schizophrenia: the role of working memory

Schizophrenia typically results in reduced performance on the Wisconsin Card Sorting Test (WCST). In the current study, we used a variety of approaches to examine the role of working memory (WM) in this deficit. One approach was to examine patterns of perseverative and non-perseverative errors. A second approach involved the comparison of the standard WCST to a modified version that used visual cues to reduce demands on WM. A third approach was to quantify the impact of WM demands on performance on a trial by trial basis. Consistent with theories of WM, the schizophrenia group showed increases in both perseverative and non-perseverative errors and differences between individuals with schizophrenia and controls were largest when WM demands were high. The visual cues helped the schizophrenia group overcome the high WM demands of the test, although they did not reduce the impairment in terms of standard scoring procedures. All impairments disappeared, however, after controlling for group differences on a measure of the speed of encoding information in WM. The pattern of results supports the conclusion that WM impairment contributes to poor performance on the WCST in individuals with schizophrenia, with additional evidence that this impairment results from generalized slowing of information processing.     

Correlation of Wisconsin Card Sorting Test performance with eye tracking in schizophrenia

The authors studied the relationship between performance on the Wisconsin Card Sorting Test and on the Trailmaking-B test and measures of smooth pursuit eye movements in 12 patients with chronic schizophrenia and 12 normal volunteers. They found that performance on the Wisconsin Card Sorting Test was significantly correlated with measures of smooth pursuit eye movements in schizophrenic patients but not in normal subjects. Trailmaking-B scores, however, were unrelated to smooth pursuit eye movements in either group.     

Wisconsin Card Sorting Test: an indicator of vulnerability to schizophrenia?

The Wisconsin Card Sorting Test (WCST) is a neuropsychological test, hypothesized to be an indicator of dorsolateral prefrontal cortex (DLPFC) functioning. The performance of schizophrenic patients in our sample (off medication) was worse than the performance of healthy controls in all variables of the WCST, including perseverative responses (PR) as well as non-perseverative responses (NPR). The rate of perseverative and non-perseverative responses was neither a function of the severity of the illness (measured by SANS/SAPS scales) nor the duration of the disease. Healthy siblings of schizophrenic probands revealed more perseverative responses than healthy controls, but did not show any difference with respect to the non-perseverative responses. This finding suggests that the difficulty to shift a cognitive set, reflected by the frequency of perseverative responses, is in favor of the WCST as a vulnerability marker for schizophrenia, whereas non-perseverative responses presumably indicate a state, but not a trait marker of the disease. However, the usefulness of this indicator may be limited by its association with age, which is worthy of being studied in closer detail.     

Wisconsin Card Sorting Test performance as a measure of frontal lobe damage.

We examined the sensitivity and specificity of the Wisconsin Card Sorting Test (WCST) as a measure of frontal lobe damage in 91 subjects with stable focal brain lesions. Anatomical information about the location and extent of brain damage was obtained from MR and CT transparencies. No significant differences in WCST performance were found between subjects with frontal vs. nonfrontal damage. Some subjects with extensive frontal lobe damage performed well on the WCST, and some subjects with damage outside of the frontal lobes failed. The optimal cutoff scores for discriminating frontal from nonfrontal subjects correctly classified only 62% of the subjects. Further analysis of WCST performances associated with damage to various subregions of the frontal lobes also failed to reveal any reliable relationships. These findings indicate that performance on the WCST cannot be interpreted in isolation as an index of frontal lobe damage.     

Impaired Wisconsin Card Sorting Test performance in first-episode severe depression

An important issue in the practice of clinical neuropsychology is to define the degree to which impaired executive functions associated with severe depression are a result of organic dysfunction or of only current depressive experience, reflecting clinical state. Twenty-eight patients with psychotic depression, 29 with nonpsychotic depression and 30 healthy controls, matched for age and education were tested on WCST, WAIS-R, and the Rorschach according to the Comprehensive System, providing indices of depression (DEPI) and coping deficit (CDI). Patients were impaired in WCST performance. The stepwise regression for WCST scores yielded two significant predictor variables: the DEPI and Digit Symbol as a measure of complex attention and response speed. Within the groups, Picture Completion in patients with nonpsychotic depression and the CDI in patients with psychotic depression emerged as the significant predictors of WCST scores. Patients with severe major depressive disorder have profound executive impairments as assessed by the WCST at early stages of the illness. Intense emotional distress and psychomotor retardation seem to contribute to impaired performance. The depression groups revealed different response patterns, reflecting more severe deterioration and signs of possible organic dysfunction in patients with psychotic depression.     

Relationship of good and poor Wisconsin Card Sorting Test performance to illness duration in schizophrenia: a cross-sectional analysis

The authors investigated whether schizophrenic patients with good and poor performance on the Wisconsin Card Sorting Test (WCST) showed cognitive modifications related to duration of illness. Of the 154 patients evaluated with the WCST, 56 subjects had normal or mildly impaired performance and 98 showed impairment on the basis of the number of categories achieved (0-3 categories = poor performance). These subsamples were then cross-sectionally divided into three subsamples depending on length of illness (< 5 years, 6-10 years, > 10 years). The inclusion of 69 healthy controls allowed the effect of age to be taken into account. The schizophrenic group as a whole and the group of poor performers did not show differences in any of the WCST indices related to length of illness. Good performers instead showed improvement on the intermediate length-of-illness group (6-10 years of illness), and then decline in the third one (> 10 years). Good performers only showed a positive significant correlation between age, age at onset, educational level and successful WCST performance. Results for the poor performers support the hypothesis of no progressive 'deteriorating' course of schizophrenia, while good performers show an unstable pattern of cognitive functions. These data support the hypothesis that cognitive deficits associated with schizophrenia cannot be considered a unitary trait, but emerge along different hypothetical trajectories.     

Wisconsin Card Sorting Test performance before and after temporal lobectomy

Wisconsin Card Sorting Test (WCST) performance was studied before and after patients underwent right (n = 34) or left (n = 34) temporal lobectomy. Patients had hemisphere language dominance judged on intracarotid amobarbital testing and were free of space-occupying lesional pathology by magnetic resonance imaging (MRI). Right and left lobectomy patients did not differ before or after surgery on WCST parameters: categories completed, perseverative errors, total correct responses, total errors, nonperseverative errors, and perseverative responses. There was no relationship between WCST performance and MRI-determined hippocampal volumes or age of recurrent seizure onset. These findings are contrary to previous reports, suggesting the presence of laterality effects on preoperative WCST performance, relationships between WCST performance and age of seizure onset, and association of WCST performance and degree of mesial temporal sclerosis. Data from this study are consistent with a report on a larger group of temporal lobectomy patients, which found no laterality effect on WCST performance. The WCST seems to be of no value when attempting to lateralize seizure onset in nonlesional temporal lobe epilepsy.     

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.     

Prefrontal cortical dysfunction in depression determined by Wisconsin Card Sorting Test performance.

OBJECTIVE: Neuroimaging studies have demonstrated reduced prefrontal cortical blood flow and metabolism in depression, but the neurobehavioral significance of these observations is not yet established. METHOD: The Wisconsin Card Sorting Test, a widely used neuropsychological index of prefrontal cortical function, was administered to 79 patients with major depression who had been unmedicated for at least 28 days, to 47 patients with schizophrenia who had never received antipsychotic medication, and to 61 healthy comparison subjects. RESULTS: Depressed patients demonstrated significant deficits on multiple Wisconsin Card Sorting Test measures compared with healthy individuals. These deficits were correlated with the severity of depression and were less severe than those demonstrated by patients with schizophrenia. CONCLUSIONS: These results provide neuropsychological evidence for significant prefrontal cortical dysfunction in depression.     

Wisconsin Card Sorting Test performance over time in schizophrenia. Preliminary evidence from clinical follow-up and neuroleptic reduction studies.

Two groups of schizophrenic patients took the Wisconsin Card Sorting Test (WCST) in separate follow-up studies; a naturalistic clinical follow-up (n = 12, study 1) and a neuroleptic reduction study (n = 10, study 2). 11 of 22 subjects (50%) performed well on the task at one or both time points. In each study no group differences were found between time 1 and time 2 performance on three WCST variables. However, correlational analyses revealed considerable within-subject variation on the WCST in the study 1 sample, which was composed of younger and more acute patients than those in study 2. This variation was present despite within-subject stability on the WAIS-R Vocabulary and Block Design subtests. For the sample combined, a trend was found (p = 0.12) linking better WCST performance at either time period with higher WAIS-R Vocabulary scores. This intra-subject variability may reflect fluctuations in neuropsychological performance in schizophrenics who maintain the residual capacity to do the task. These findings highlight the importance of longitudinal studies of neuropsychological functioning in schizophrenia. Studies of larger samples are needed to confirm these initial results.     

Wisconsin Card Sorting Test deficits in chronic paranoid schizophrenia. Evidence for a relatively discrete subgroup?

Some, although not all, researchers have reported dramatically increased numbers of perseverative responses on the Wisconsin Card Sorting Test (WCST) in schizophrenic patients compared to normal comparison subjects. The current study was designed to further explore the nature of possible WCST deficits in a group of paranoid schizophrenic patients compared to normal and psychiatric comparison subjects. In the current study, schizophrenic patients had significantly greater numbers of perserverative responses on the WCST than the comparison groups. The sample of patients with schizophrenia appeared to be characterized by a non-Gaussian distribution of perseverative responses on the WCST. WCST-impaired and WCST-nonimpaired schizophrenic subgroups were compared on cognitive and symptom measures, and increased perseverative responding was associated with negative symptoms, slowed reaction time, and more hospitalizations. While additional research is necessary to further investigate hypotheses of frontal versus generalized brain dysfunction in schizophrenic patients, WCST impairment seems to be present in a clinically meaningful subgroup of paranoid schizophrenic patients.     

Wisconsin Card Sorting Test deficits in schizotypic individuals

The present study investigates executive functioning in schizotypic college students and control subjects using the Wisconsin Card Sorting Test (WCST). Inhibitory control and working memory, two aspects of executive functioning, were examined in deviantly high scorers on the Perceptual Aberration and Magical Ideation Scales (n=97), high scorers on the revised Social Anhedonia Scale (n=58), and in control subjects (n=104). The schizotypic groups displayed significantly more perseverative errors and achieved fewer categories than the control group. The two schizotypic groups did not differ from each other. We identified a subset of schizotypic individuals who also produced clinically deviant WCST profiles. The findings support the hypothesis that executive function deficits may precede the onset of schizophrenia and related illnesses.     

Assessing declarative memory in schizophrenia using Wisconsin Card Sorting Test stimuli: the Paired Associate Recognition Test

The Paired Associate Recognition Test (PART) was developed to measure declarative memory using Wisconsin Card Sorting Test (WCST) stimuli, so that both tasks could be administered during functional neuroimaging to differentiate memory and executive function, and associated frontal and temporal lobe activation in schizophrenia. The current study was designed to compare PART and WCST performance in schizophrenic patients and to examine effects of medication and symptomatology. The PART, WCST, and standard declarative memory tasks were administered to 30 chronic schizophrenic patients and 30 matched healthy control subjects. Supporting task validity was the finding that patients were equally impaired on the PART and the WCST. Neuroleptics did not appear to affect performance. The effect of anticholinergic medication correlated negatively with WCST performance in a small subsample. Severity of schizophrenia-specific symptoms measured at intake on the Brief Psychiatric Rating Scale correlated negatively with performance on the WCST. These results support the application of the PART and WCST in future functional neuroimaging studies.     

Working memory and Wisconsin Card Sorting Test performance in schizotypic individuals: a replication and extension

The present study examined spatial working memory and Wisconsin Card Sorting Test (WCST) performance in psychosis-prone individuals, either those with extremely high scores on the Social Anhedonia Scale (SocAnh; n = 49) or deviant scores on the Perceptual Aberration-Magical Ideation Scales (Per-Mag; n = 66). Sixty-three individuals with normal scores on the Chapman Psychosis-Proneness Scales served as control subjects. In order to evaluate working memory performance, participants were administered three tasks, namely, sensorimotor, degraded stimulus, and delayed-response tasks. Although the SocAnh and Per-Mag groups displayed poorer performance than control subjects on the working memory task, they did not differ significantly from each other. The SocAnh group exhibited slower reaction times on the working memory task compared to the control group. The groups did not differ in their performance on sensorimotor or degraded stimulus control tasks. Both psychosis-prone groups differed significantly from control subjects in terms of their WCST performance. Working memory performance was inversely associated with the number of perseverative errors (r = -0.17) and the number of trials to complete the first category on the WCST (r= -0.15). These findings extend the literature by indicating that some psychosis-prone individuals with social-interpersonal schizotypal deficits also display subtle spatial working memory impairments.     

Neuropsychological probes of fronto-limbic system dysfunction in schizophrenia. Olfactory identification and Wisconsin Card Sorting performance.

Schizophrenic patients and normal control subjects took the University of Pennsylvania Smell Identification Test (UPSIT) and Wisconsin Card Sorting Test (WCST) as dual neuropsychological 'probes' of orbitofrontal (OF) and dorsolateral (DL) prefrontal function respectively. Patients were significantly impaired on both tasks compared to controls. UPSIT and WCST performance were uncorrelated in patients but were positively correlated in controls. The lack of correlation found in the patients suggests that the tasks may be tapping independent dysfunctions in schizophrenia reflecting differential impairment in fronto-limbic brain systems. Individual profiles of preserved and impaired performance on the UPSIT and WCST suggested that three schizophrenic patients had OF dysfunction, five had DL dysfunction and seven had a generalized (OF and DL) frontal system dysfunction. The reduced ability of schizophrenic patients to identify odors was largely independent of many deficits or confounds typically associated with schizophrenia and did not appear to be simply a function of generalized deficit. These data are preliminary and require replication with larger samples and validation with other measures of fronto-limbic system dysfunction.     

Scaffolded instruction remediates Wisconsin Card Sorting Test deficits in schizophrenia: A comparison to other techniques

Errorless learning without fading (ELWF) and the method of vanishing cues (MVC) have been widely researched in rehabilitation contexts, but little is known about their effectiveness relative to each other. With respect to explicit memory, it was hypothesised that the MVC can lead to better performance than ELWF for those with less severe memory difficulties, provided that it elicits effortful but successful study‐trial recall. This hypothesis was supported in two studies involving participants with less severe memory difficulties following acquired brain injuries, using free recall as the measure of explicit memory. With respect to implicit memory, it was suggested, on the basis of the transfer appropriate processing approach, that the relative effectiveness of the two methods will depend on the way in which memory is tested. Specifically, it was hypothesised that the MVC would be more effective than ELWF on a stem completion task, equally effective on a free association task, and less effective on a perceptual identification task. These hypotheses were supported in the two studies involving participants with brain injuries, and in two larger studies involving university students. The implications of these findings for the use of these methods in rehabilitation are discussed. It is argued that the MVC may be more effective when the task can be learnt explicitly, the learner retains significant explicit memory ability and the study‐trial recall is effortful but successful. With respect to implicit memory, one interpretation of the findings is that, in most practical contexts, neither method will have any intrinsic advantage, although ELWF may be preferable because it is more effective in eliminating errors. However, this suggestion is very tentative because of issues concerning the generalisability of the present findings, and further research is recommended.