Errors In Wisconsin Card Sorting Test Research Articles

Dysfunction of circulating endothelial progenitor cells in major depressive disorder.

Despite mounting evidence demonstrates circulating endothelial progenitor cells (cEPCs) quantitative changes in depression, no study has investigated cEPC functions in major depressive disorder (MDD). We investigated the role of cEPC adhesive and apoptotic functions in MDD. We recruited 68 patients with MDD and 56 healthy controls (HCs). The depression symptoms, anxiety, psychosomatic symptoms, subjective cognitive dysfunction, quality of life, and functional disability were evaluated using the Hamilton Depression Rating Scale and Montgomery-Åsberg Depression Rating Scale, Hamilton Anxiety Rating Scale, Depression and Somatic Symptoms Scale (DSSS), Perceived Deficits Questionnaire-Depression, 12-Item Short Form Health Survey (SF-12), and Sheehan Disability Scale (SDS), respectively. Working memory and executive function were assessed using a 2-back task and Wisconsin Card Sorting Test (WCST). Inflammatory marker (soluble interleukin-6 receptor, C-reactive protein, and tumor necrosis factor-α receptor-1), cEPC adhesive, and apoptotic levels were measured using in vitro assays. The MDD patients showed significantly lower cEPC adhesive levels than the HCs, and this difference in adhesive function remained statistically significant even after adjusting for inflammatory marker levels. The cEPC adhesion levels were in inverse correlations with commission and omission errors in 2-back task, the percent perseverative response and percent perseverative errors in WCST, and the DSSS and SDS scores, but in positive correlations with SF-12 physical and mental component scores. cEPC apoptotic levels did not differ significantly between the groups. The findings indicate that cEPC adhesive function is diminished in MDD and impacts various aspects of cognitive and psychosocial functions associated with the disorder.

Impact of subjective sleep quality on objective measures of neurocognitive dysfunction in patients with major depressive disorder

Background: Sleep disturbances are prevalent in major depressive disorder (MDD). MDD and sleep disturbances are both linked to cognitive impairments. Studies exploring the mechanisms and impact of sleep disturbances on neurocognitive functioning in depressed patients are lacking and proper assessment and therapeutic interventions for sleep disturbances are not part of clinical management of MDD. Aim: We investigated the association between subjective sleep quality and neurocognitive dysfunction in patients with MDD. Materials and Methods: Patients with moderate MDD episode were matched and assigned to two groups with poor and good sleep quality. We used Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. To measure frontotemporally mediated cognitive functioning, following tests were administered: Wisconsin Card Sorting Test (WCST) and degraded continuous performance test (CPT-DS). Two-tailed independent samples t tests or Mann–Whitney U tests and Pearson’s correlation coefficient were performed for the statistical analysis of sleep latency, sleep duration, overall sleep quality, CPT d’ value, WCST correct answers, errors, and perseverative errors. Results: Participants with MDD and poor sleep quality performed worse on cognitive tests compared to patients with MDD and good sleep quality. Scores of subjective sleep on PSQI positively correlated with WCST errors (r (60) =0.8883 P = .001) and negatively correlated with WCST correct answers (r (60) = -.869 P = .001) and measures of CPT-DS d’ value (r (60) = -.9355 P = .001). Conclusions: Poor sleep quality, notably sleep duration and sleep latency, worsens the neurocognitive impairments of MDD patients. As these impairments are found to be associated with treatment outcomes, sleep disturbances should be additionally assessed and treated in MDD episode.

Consequences of diabetes and pre-diabetes and the role of biochemical parameters of carbohydrate metabolism for the functioning of the prefrontal cortex in obese patients.

The role of executive functions (EF) is to maintain particular behaviours in order to achieve intended goals. EF are crucial in management of pre-diabetes, diabetes and obesity which are grievous diseases and can lead to severe complications. The aims of our study were to: assess EF in group of obese subject with carbohydrate disorders, evaluate whether biochemical factors and comorbidities related to metabolic disorders have adverse effect on EF in this group of patients. The study included 185 obese patients (146 women; 39 men) who were divided on three groups: pre-diabetic, diabetic and control subgroup. Patient underwent Wisconsin Card Sorting Test (WCST) to evaluate EF. Assessed biochemical factors included C-peptide, fasting plasma glucose (FPG) and glycosylated hemoglobin A1c (HbA1c). Diabetic patients showed the worst WCST scores among the rest of groups. Pre-diabetic individuals did not differ in EF performance from control subgroup. We observed significant correlations between FPG and HbA1c and worse WCST scores in pre-diabetic subgroup. In diabetic patients C-peptide correlated with poorer EF. Depressive symptoms and hypertension significantly correlated with non-perseverative errors in WCST. The subgroup of diabetic patients were the most obese and had the worst glycemia parameters. They also showed the worst EF in WCST. According to obtained results, hyperglycemia positively correlated with poor EF in pre-diabetes. However, in diabetic subjects cognitive deterioration may results from insulin resistance rather than hyperglycemia. In obese individuals with carbohydrate disorders both hypertension and depressive symptoms significantly contributed to EF dysfunction.

A process approach to verbal memory assessment: Exploratory evidence of inefficient learning in women remitted from anorexia nervosa

ABSTRACTIntroduction: Anorexia nervosa (AN) is associated with deficits in set-shifting and cognitive flexibility, yet less is known about the persistence of these deficits after recovery and how they might contribute to reported difficulties organizing and learning new information. To address this question, the current study applied a process-focused approach, that accounts for errors and strategies by which a score is achieved, to investigate the relationship between verbal memory and executive function in women remitted from AN.Method: Twenty-six women remitted from anorexia nervosa (RAN) and 25 control women (CW) aged 19–45 completed the California Verbal Learning Test, Second edition (CVLT-II) and the Wisconsin Card Sorting Test (WCST). Groups were compared on overall achievement scores, and on repetition, intrusion, and perseverative errors on both tests. Associations between learning and memory performance and WCST errors were also examined.Results: RAN and CW groups did not differ on overall CVLT-II learning and memory performance or errors on the WCST, though the RAN group trended towards greater WCST non-perseverative and total errors. On the CVLT-II, the RAN group made significantly more repetition errors than CW (p = 0.010), and within-trial perseveration (WTP) errors (p = 0.044). For the CW group, CVLT-II learning and memory performance were negatively associated with errors on the WCST, whereas among RAN, primarily delayed memory was negatively correlated with WCST errors. Notably, for RAN, greater WCST perseverative responses were correlated with greater CVLT-II repetition and WTP errors, showing the convergence of perseverative responding across tasks.Conclusions: Despite similar overall learning and memory performance, difficulties with executive control seem to persist even after symptom remission in patients with AN. Results indicate an inefficient learning process in the cognitive phenotype of AN and support the use of process approaches to refine neuropsychological assessment of AN by accounting for strategy use.

Cognitive dysfunction and negative symptoms in patients with schizophrenia and their first-degree relatives from simplex and multiplex families.

PurposeThis study aimed to investigate cognitive functioning, negative symptoms, and the relationships in schizophrenia (SP) pedigrees and to explore the effect of genetic loading on those endophenotypes.Patients and methodsForty-four patients with SP, 81 first-degree non-psychotic relatives of patients from simplex and multiplex families, 14 matched control probands, and 29 first-degree relatives of the patients from communities were assessed by the vocabulary subtest (VS) of Wechsler Adult Intelligence Scale, memory span subtests of the Multiple Memory Assessment Scale (MMAS), Wisconsin Card Sorting Test (WCST), Continuous Performance Test (CPT), and Negative Scale of Positive and Negative Syndrome Scale.ResultsCompared with controls, patients with SP and their relatives had worse performances in WCST and CPT, and more serious negative symptoms. Patients from multiple families performed poorly on most tests while patients from simplex families had impairments only on the parameters of CPT and WSCT as compared to control probands. Patients from multiple families differed significantly from the patients from simplex families in the digit span and word span of MMAS. After controlling for education, in comparison with relatives of control probands, relatives from multiple families showed impairments in VS, multiple domains of CPT, whereas relatives from simplex families had lower scores on the VS and more total cards and random errors in WSCT. The performances of most tests were linked to negative symptoms in patients with SP. For patients with SP, VS, correct numbers and categories in the WCST, and visual and acoustic errors in the CPT predicted 68.8% of the variability in negative symptoms.ConclusionOur findings support that cognitive deficits and negative symptoms may be markers of hereditary susceptibility of SP and aggravate as the degree of genetic load increases. There are certain relationships between cognitive deficits and negative symptoms in patients with SP.

Higher IQ in juvenile myoclonic epilepsy: Dodging cognitive obstacles and “masking” impairments

Executive deficits and impulsiveness are extensively reported in juvenile myoclonic epilepsy (JME). Previous literature suggests that intelligence may mediate these deficits. In this study, we evaluated and compared the performance of adults with JME with high and low intelligence quotient (IQ) and controls on tasks for executive function (EF) and impulsive traits. We investigated the neuropsychological performance of 53 adults with JME and below average IQ (57% women; 26.9 [±7.88] years; mean IQ: 89.8 [±5.1]), 26 adults with JME and average or above average IQ (53.8% women; 28.2 [±9.33] years; mean IQ: 110.7 [±8.3]), 38 controls with below average IQ (55% women; 28.4 [±8.4] years; mean IQ: 90.1 [±5.8]), and 31 controls with average or above average IQ (61.3% women; 32.20 [±11.3] years; mean IQ: 111.6 [±10.5]) with a comprehensive battery of neuropsychological tests that measure executive/attentional function. Impulsive traits were assessed using the Cloninger et al.'s Temperament and Character Inventory (novelty seeking (NS) domain). The group with JME with higher IQ presented worse performance compared with controls with higher IQ on Controlled Oral Word Association (COWA) and Wisconsin Card Sorting Test (WCST) (errors). This group showed worse performance than controls with lower IQ on Stroop Color–Word Test (SCT) 1, Trail Making (TM) A, COWA, and WCST (errors). Patients with lower IQ showed worse performance than controls with higher IQ on Digit Span Forward (DSF), Digit Span Backward (DSB), SCT1, SCT2, SCT3, TM A, COWA, and WCST (errors and failure to maintain set). Patients with lower IQ showed worse performance than controls with lower IQ on DSF, DSB, SCT1, SCT2, SCT3, TM A, TM B, COWA, and WCST (errors and failure to maintain set). Patients from groups with low and high IQ showed higher scores than controls with higher and lower IQ on impulsivity for NS1 and NS2 (except for patients with higher IQ versus controls with lower IQ). Adults with JME and higher IQ show less evidence of EF deficits compared with those with JME and below average IQ, suggesting that a higher degree of intellectual efficiency may act as a compensatory mechanism. However, it does not minimize some aspects of impulsive traits. Patients with JME and higher cognitive reserve may create strategies to dodge their cognitive obstacles. In this context, intelligence may protect and, at the same time, “mask” impairments that could be detected earlier.

Disorganization at the stage of schizophrenia clinical outcome: Clinical–biological study

BackgroundAccording to the multidimensional model of schizophrenia, three basic psychopathological dimensions constitute its clinical structure: positive symptoms, negative symptoms and disorganization. The latter one is the newest and the least studied. Our aim was to discriminate disorganization in schizophrenia clinical picture and to identify its distinctive biological and socio-psychological particularities and associated genetic and environmental factors. MethodsWe used SAPS/SANS psychometrical scales, scales for the assessment of patient's compliance, insight, social functioning, life quality. Neuropsychological tests included Wisconsin Card Sorting Test (WCST), Stroop Color-Word test. Neurophysiological examination included registration of P300 wave of the evoked cognitive auditory potentials. Environmental factors related to patient's education, family, surrounding and nicotine use, as well as subjectively significant traumatic events in childhood and adolescence were assessed. Using PCR we detected SNP of genes related to the systems of neurotransmission (COMT, SLC6A4 and DRD2), inflammatory response (IL6, TNF), cellular detoxification (GSTM1, GSTT1), DNA methylation (MTHFR, DNMT3b, DNMT1). ResultsDisorganization is associated with early schizophrenia onset and history of psychosis in family, low level of insight and compliance, high risk of committing delicts, distraction errors in WCST, lengthened P300 latency of evoked cognitive auditory potentials, low-functional alleles of genes MTHFR (rs1801133) and DNMT3b (rs2424913), high level of urbanicity and psychotraumatic events at early age. ConclusionsSevere disorganization at the stage of schizophrenia clinical outcome is associated with the set of specific biological and social–psychological characteristics that indicate its epigenetic nature and maladaptive social significance.

Reduced Dopamine Transporter Availability and Neurocognitive Deficits in Male Patients with Alcohol Dependence.

Dopamine plays an important role in the development of alcohol dependence, cognitive dysfunction, and is regulated via dopamine transporter activity. Although dopamine transporter activity is critically involved in alcohol dependence, studies observing this relationship are limited. Thus the current study examined whether dopamine transporter availability is associated with developing of alcohol dependence and cognitive dysfunction. Brain imaging with 99mTc-TRODAT-1 as a ligand was used to measure dopamine transporter availability among 26 male patients with pure alcohol dependence and 22 age- and sex- matched healthy volunteers. The Wisconsin Card Sorting Test (WCST) and Tridimensional Personality Questionnaire (TPQ) were administered to assess neurocognitive functioning and personality traits, respectively. Compared to healthy controls, patients with alcohol dependence showed a significant reduction in dopamine transporter availability (p < 0.001), as well as diminished performance on the WCST (p < 0.001). Dopamine transporter availability was negatively correlated with both total and perseverative WCST errors among healthy controls, but only patients with alcohol dependence showed a positive correlation between dopamine transporter availability and a harm avoidance personality profile. Thus, reductions in dopamine transporter availability may play a pathophysiological role in the development of pure alcohol dependence, given its association with neurocognitive deficits. Moreover, personality may influence the development of pure alcohol dependence; however, additional clinical subgroups should be examined to confirm this possibility.

Glutamatergic metabolite correlations with neuropsychological tests in first episode schizophrenia

Increased glutamatergic metabolites have been found in first episode schizophrenia. Although abnormal neuropsychological functioning has been demonstrated to be a core feature of schizophrenia, no studies have examined glutamatergic metabolites and neuropsychological function in drug-naïve patients. The present study addressed whether higher levels of glutamatergic metabolites would be associated with poorer neuropsychological performance and social functioning in first episode patients. Glutamatergic concentration estimates were obtained from the left anterior cingulate cortex (ACC) and thalamus at baseline and 10 months after treatment in 16 patients with psychosis using 4.0T 1H magnetic resonance spectroscopy. A neuropsychological test battery was administered at baseline and 1 year. In the ACC, baseline glutamine was associated with performance on the Paced Auditory Serial Addition Task (PASAT). Glutamate at 10 months was associated with Wisconsin Card Sorting Test (WCST) errors and Trail-Making Test-B duration. Glutamine at 10 months was positively associated with WCST errors and negatively associated with WCST categories completed. In the thalamus, baseline glutamine was negatively associated with performance on the PASAT. Thalamic glutamate at baseline showed a trend towards a negative association with social functioning at 5 years. Glutamatergic metabolites were associated with neuropsychological test deficits and impaired social functioning at 5-year follow-up in patients with first episode psychosis, findings suggestive of an association between glutamatergic alterations on neurotoxicity early in the course of schizophrenia.

Factors related with the ability to maintain wakefulness in the daytime after fast and forward rotating shifts

The aim of this study was to explore changes in cognitive function, sleep propensity, and sleep-related hormones (growth hormone, cortisol, prolactin, and thyrotropin) and to investigate the factors related to the ability to maintain wakefulness in the daytime after one block of fast forward rotating shift work (2 days, 2 evenings, and 2 nights). Twenty female nurses (mean age: 26.0 ± 2.0 years; range: 22–30 years) were recruited from an acute psychiatric ward. The nurses completed the Maintenance of Wakefulness Test (MWT), State Anxiety Inventory (SAI), Stanford Sleepiness Scale (SSS), Digit Symbol Substitution Test, Symbol Searching Test, Taiwan University Attention Test, Wisconsin Card Sorting Test (WCST), and Multiple Sleep Latency Test (MSLT) four times throughout the day at 2-hour intervals, and their hormone levels were measured at the same time. There was no time of day effect on sleep propensity as measured by the MWT or MSLT despite an increase in self-reported sleepiness. Anxiety state and neuropsychological tasks, including executive function, attention, and perceptual and motor abilities were not affected during the daytime sleep restriction period. The number of omissions and perceptual and motor abilities showed a practice effect. The thyrotropin levels were significantly elevated, and cortisol levels significantly decreased during the daytime sleep restriction period. There were no significant changes in growth hormone or prolactin throughout the daytime period. Age was negatively associated with the mean sleep latency (MSL) of the MWT and positively associated with the MSL of the MSLT. The perseverative errors in WCST and SSS scores were negatively associated with the MSL of the MWT. SAI scores and thyrotropin levels were positively associated with the MSL of the MWT. In conclusion, there was no change in sleep propensity in the daytime after one block of rotating shift work. An attempt to preserve daytime alertness was also related to maintaining neuropsychological performance. Maintaining this ability was related to thyrotropin and age, and this cognition required a high attentive load.

Basic symptoms and neurocognition: preliminary comparison of first-episode psychosis vs multi-episode long-term illness

Schizophrenia is preceded by basic symptoms which may persist after long time and include subjective cognitive impairment. Furthermore, it is characterised by cognitive deficits that may deteriorate with the progression of illness. To examine the relationship between neurocognition and basic symptoms along the course of schizophrenia, we compared the cognitive performance and the basic symptoms of one population with first episode psychosis (FEP) and one with a chronic, multi-episode course (MEP). We tested 8 FEP (5 male) and 7 MEP (7 male) in- and outpatients, for basic symptoms with the Schizophrenia Proneness Instrument-Adult version (SPI-A) and for neurocognition with Raven's Color Progressive Matrices (CPM), Rey-Osterrieth's complex figure (Rey), Corsi's and Buschke-Fuld tests, the Wisconsin Card Sorting Test (WCST), the Stroop test, and the Trail Making Test (TMT). FEP patients did not differ from MEP patients as for SPI-A scores. MEP patients were significantly more impaired on several subtests of Buschke-Fuld, the Rey, and the WCST with respect to FEP. Impairment on the cognitive subscale of the SPI-A correlated with non-perseverative WCST errors, and on the self subscale of the SPI-A with impaired performance on the Buschke-Fuld. Further, in MEP, impairment on the body subscale of the SPI-A correlated inversely with number of categories completed of the WCST. Basic symptoms persist throughout the phases of schizophrenia and are relatively independent of cognitive performance. A chronic, multi-episode course is associated with increased cognitive impairment in schizophrenia.

Developing models of how cognitive improvements change functioning: Mediation, moderation and moderated mediation

BackgroundCognitive remediation (CRT) affects functioning but the extent and type of cognitive improvements necessary are unknown. AimTo develop and test models of how cognitive improvement transfers to work behaviour using the data from a current service. MethodParticipants (N49) with a support worker and a paid or voluntary job were offered CRT in a Phase 2 single group design with three assessments: baseline, post therapy and follow-up. Working memory, cognitive flexibility, planning and work outcomes were assessed. ResultsThree models were tested (mediation — cognitive improvements drive functioning improvement; moderation — post treatment cognitive level affects the impact of CRT on functioning; moderated mediation — cognition drives functioning improvements only after a certain level is achieved). There was evidence of mediation (planning improvement associated with improved work quality). There was no evidence that cognitive flexibility (total Wisconsin Card Sorting Test errors) and working memory (Wechsler Adult Intelligence Scale III digit span) mediated work functioning despite significant effects. There was some evidence of moderated mediation for planning improvement if participants had poorer memory and/or made fewer WCST errors. The total CRT effect on work quality was d=0.55, but the indirect (planning-mediated CRT effect) was d=0.082 ConclusionPlanning improvements led to better work quality but only accounted for a small proportion of the total effect on work outcome. Other specific and non-specific effects of CRT and the work programme are likely to account for some of the remaining effect. This is the first time complex models have been tested and future Phase 3 studies need to further test mediation and moderated mediation models.

Individual differences in cortisol levels and performance on a test of executive function in men and women

Despite evidence for a high concentration of corticosteroid receptors in prefrontal cortex, little research has examined the relationship between cortisol and prefrontal cortical function other than working memory. We investigated the association between salivary cortisol levels and performance on the Wisconsin Card Sorting Test (WCST) of executive function and on a test of mental rotation (to test specificity of the relationship between cortisol and cognitive performance) in men and women ( n = 116, ages 17–22). Higher cortisol levels at the beginning of the test session were associated with more errors in women on the WCST and fewer errors in men. However, men's cortisol levels were lower than women's at this point in time. Cortisol levels were not associated with mental rotation scores. Our results suggest that individual differences in cortisol levels among participants upon arrival to a test situation influence performance on a task involving the prefrontal cortex.

Very-low-birthweight and term small-for-gestational-age adolescents: attention revisited.

To assess whether adolescents with very low birthweight (VLBW) and peers born small for gestational age (SGA) at term are at a disadvantage when attending to or executing tasks. Cohorts of 54 VLBW (<or=1,500 g), 60 SGA and 83 controls were tested with the Knox Cube Test, Conners' Continuous Performance Test (CPT II), Stroop Colour-Word Test, Trail Making Test (TMT) A & B, and Wisconsin Card Sorting Test (WCST). IQ was estimated using the subtests vocabulary and picture arrangement of WISC III. VLBW adolescents scored worse than controls on Knox Cube Test, Stroop Colour-Word Test, TMT A & B and WCST, whereas term SGA adolescents only made more non-perseverative errors in WCST and more errors in the interference condition of the Stroop Colour-Word Test. Thirty-two (38.6%) adolescents in the control group had poor performance (< 2 SD) on at least one of the tests compared with 40 (74.1%) VLBW (p<0.01) and 32 (53.3%) SGA adolescents (not significant). VLBW adolescents are at risk of disadvantage in aspects of attention and/or executive functions. The adverse effects of being born SGA at term appear to be few in these domains of cognitive function.

‘Prefrontal’ cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: An exploratory [18F]‐fluoro‐L‐DOPA‐PET investigation

Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron-emission-tomography (PET) studies, net blood-brain clearance of [18F]-fluoro-l-DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood-brain clearance of FDOPA (K(in)(app)) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes-of-interest. The Wisconsin-Card-Sorting-Test (WCST), Stroop-Test, Trail-Making-Test (TMT-A/B), and Continuous-Performance-Test (CPT-M) had been administered previously to the same subjects. No correlation of K(in) (app) with perseverative errors in WCST or age could be found. However, there were significant positive correlations between the magnitude of K(in)(app) in caudate nucleus, putamen, and midbrain with performance of the TMT-B, CPT-M, and the Stroop test. Highest correlations were found between the time needed to perform the Stroop interference task and the K(in)(app) of striatal areas (Caudate nucleus: -0.780, P = 0.005; putamen: -0.870, P < 0. 001). Thus, the present findings reveal a strong correlation between dopamine synthesis capacity in striatum of healthy volunteers and performance of cognitive tasks linked to the prefrontal cortex.

Very‐low‐birthweight and term small‐for‐gestational‐age adolescents: Attention revisited

Abstract Aim: To assess whether adolescents with very low birthweight (VLBW) and peers born small for gestational age (SGA) at term are at a disadvantage when attending to or executing tasks. Methods: Cohorts of 54 VLBW (≤1500 g), 60 SGA and 83 controls were tested with the Knox Cube Test, Conners’ Continuous Performance Test (CPT II), Stroop Colour‐Word Test, Trail Making Test (TMT) A &amp; B, and Wisconsin Card Sorting Test (WCST). IQ was estimated using the subtests vocabulary and picture arrangement of WISC III. Results: VLBW adolescents scored worse than controls on Knox Cube Test, Stroop Colour‐Word Test, TMT A &amp; B and WCST, whereas term SGA adolescents only made more non‐perseverative errors in WCST and more errors in the interference condition of the Stroop Colour‐Word Test. Thirty‐two (38.6%) adolescents in the control group had poor performance (&lt; 2 SD) on at least one of the tests compared with 40 (74.1%) VLBW (p&lt;0.01) and 32 (53.3%) SGA adolescents (not significant). Conclusion: VLBW adolescents are at risk of disadvantage in aspects of attention and/or executive functions. The adverse effects of being born SGA at term appear to be few in these domains of cognitive function.

Executive functions in young patients with unipolar depression

Neuropsychological deficits associated with unipolar depression are seen in a broad range of cognitive domains. Executive deficits may be prominent in depression. Investigation of executive functions in younger adult patients with unipolar depression has been the focus of our study. Twenty-two consecutively depressive inpatients (24-36 years) and 21 healthy control subjects, matched on age, gender, education and verbal IQ were included in the study. Neuropsychological tests for executive functions were applied to all subjects. Unipolar young depressives showed significantly reduced number of completed categories and more trials for completion of the first category on Wisconsin Card Sorting Test (WCST). No difference of tasks assessing the short-term memory, total errors on WCST, perseverative and non-perseverative errors, and of both phonemic and semantic conditions of verbal fluency was found between groups. The results suggested that unipolar depressives had specific cognitive style characterized by "negative cognitive set" (stronger negative reaction to negative feedback) and by failure to use negative feedback to improve their performance.

Higher brain function disturbance in Parkinson's disease patients: an evaluation based on electrophysiological investigation

Background: Higher brain function disturbance such as the central executive of working memory impairment is thought to exist even in early-stage nondemented idiopathic Parkinson's disease patients (PDPs). Methods: Resting EEG, simple oddball paradigm and novel task event-related potentials (ERPs) topography were measured in early-stage nondemented PDPs (MMSE>26), and age-matched normal controls (NCs). The new modified Wisconsin Card Sorting Test (WSCT) was used to evaluate the frontal lobe function. Results and interpretation: There were no natural novelty P3s to be found in PDPs. P3b latency did not differ between PDPs and controls. In addition, increased P3b amplitude for the target stimulus was found in nondemented PDPs. Moreover, the nondemented PDPs showed increased amplitude of resting EEG. PDPs showed significant decreasing of the achieved categories and increasing of perseverative errors in WSCT. Conclusions: The results of the present study suggest that higher brain function disturbance such as the central executive of working memory impairment in nondemented PDPs may be based on the disturbance of mental set change, parallel processing and inhibition of the cortical function due to dysfunction of basal ganglia.

Mental set change and parallel processing in Parkinson's disease: a multimodal P3 analysis

The purpose of our study was to demonstrate working-memory impairment in nondemented early stage mild Parkinson's disease patients (PDPs) electrophysiologically using a multimodal event-related potentials (ERP) paradigm. Multimodal ERP paradigm was performed in 21 nondemented medicated early stage PDPs (MMSE>24) and 16 age-matched normal control subjects (NCs). Twenty channels of ERP were recorded from scalp. The global field power (GFP) was employed for ERP components analysis. The new modified Wisconsin Card Sorting Test (WSCT) was used to evaluate frontal lobe function. No novelty P3s were detected in PDPs. P3 GFP latency to nontarget novel stimulus in visual and auditory modalities was significantly longer in PDPs than in the NCs. P3 GFP amplitude for the target stimulus (P3b) was higher in PDPs in both auditory and visual modalities. P3b GFP latency, however, was not different between the two groups. PDPs showed a significantly lower score of achieved categories and deterioration of perseverative errors in WSCT compared to the NCs. Our results suggest that nondemented mild PDPs do not have sufficient mental resources to allocate to the central executive as indicated by the lack of novelty P3 which may be due to the disability of the working memory.

Both random and perseverative errors underlie WCST deficits in prefrontal patients

The specificity of the Wisconsin Card Sorting Test (WCST) as a marker of frontal lobe pathology remains controversial. One problem is the lack of a well established correspondence between WCST errors and specific cognitive or neural processes. The conventional scoring of non-perseverative WCST errors does not discriminate between errors related to the efficient test of hypotheses during set shifting (‘efficient errors’), and random failures to maintain set (‘random errors’). This inherent confusion in the non-perseverative error score probably minimizes the relative importance of random errors in frontal lobe pathology. In this study, we used a WCST version sensitive to differences between ‘efficient’ and random errors to examine set shifting deficits in patients with focal lesions to their lateral prefrontal cortex. As expected, patients showed abnormally high rates of perseverative errors. Interestingly, patients also showed enhanced rates of random errors suggesting constant shifts or fluctuations in their choice of sorting principle. These results suggest that more sensitive tests are needed to elucidate the association between a specific type of set shifting error and a particular type of frontal lobe pathology.