Attentional and eye tracking deficits correlate with negative symptoms in schizophrenia

Thirty patients with a DSM-III-R diagnosis of schizophrenia were assessed for severity of schizophrenic symptoms using the Brief Psychiatric Rating Scale (BPRS) and were tested on a Continuous Performance Test (CPT) and a smooth pursuit eye tracking task. Negative symptoms were significantly correlated with eye tracking impairment ( r=0.43, p<0.01) and CPT deficits ( r=0.67, p<0.001), but performance on neither task was correlated with positive symptoms. CPT performance and eye tracking performance were modestly correlated with each other ( r=0.39, p<0.01) and CPT performance was found to be a stronger predictor of negative symptoms than eye tracking performance. These data indicate that neurocognitive markers of vulnerability to schizophrenia are associated with negative rather than positive symptoms

Information-processing markers of vulnerability to schizophrenia: performance of patients with schizotypal and nonschizotypal personality disorders

Deficits in performance on tests of information processing have been proposed to be markers of vulnerability to schizophrenia. Very few of the previous studies of these information-processing deficits, however, have examined subjects who have clinical diagnoses of schizotypal personality disorders; most studies instead have focused on schizophrenic patients and their relatives or subjects selected on the basis of psychometric evidence of schizotypal traits. In this study, patients with DSM-III schizotypal ( n = 29) and non-odd cluster ( n = 33) personality disorders were examined with the Continuous Performance Test (CPT) and a backward masking test and compared with a group of normal volunteers ( n = 31). Patients with schizotypal personality disorder manifested a specific deficit in performance, making significantly more errors of omission in the degraded stimulus condition of the CPT compared with the nondegraded condition, whereas non-odd cluster patients and the normal volunteers performed the same in both conditions. No differences in performance between the groups were found for any of the backward-masking measures. These data suggest that specific deficits in CPT performance, possibly reflecting reduced processing capacity or load responsiveness of the vigilance system, are associated with schizotypal personality disorder and fail to replicate previous studies finding backward-masking deficits in various nonclinical schizotypal populations

A pen-and-paper human analogue of a monkey prefrontal cortex activation task: spatial working memory in patients with schizophrenia

In order to pursue the hypothesis that the dorsolateral prefrontal cortex is a source of cognitive deficit in schizophrenia, we developed an easily administered pen-and-paper human analogue of a visuospatial working memory task that in non-human primates activates the neurons of Walker area 46 (Goldman-Rakic, 1987). Compared to normal controls, schizophrenic patients made significantly greater errors in identifying where a visuospatial stimulus had been presented to them 30 and 60 seconds earlier, and these differences were significantly greater than in an immediate recall condition. These data suggest that schizophrenic patients have visuospatial working memory deficits that are sensitive to pen-and-paper versions of the tasks that activate the Walker area 46 in non-human primates. The availability of an easily administered test that may be associated with the functioning of the prefrontal cortex may enable more specific assessment of this brain region in humans

Performance of nonpsychotic relatives of schizophrenic patients on cognitive tests

We tested 54 nonpsychotic first degree relatives of 23 schizophrenic probands and 18 control subjects matched for age and education on several neuropsychological tests. The tests were selected to assess overall intellectual ability or because previous work indicated that they are particularly sensitive measures of cognitive dysfunction in schizophrenic patients. The relatives of schizophrenic patients performed significantly worse than the control subjects on tests of verbal fluency and on Trailmaking, part B. Each of these tests contributed unique variance to the discrimination between groups. The groups did not differ significantly on the number of perserverative errors on the Wisconsin Card Sorting Test, Wechsler Adult Intelligence Scale-Revised block design or vocabulary, or Trailmaking, part A. Eight relatives who met DSM-III-R criteria for schizotypal personality disorder were more impaired than the remaining 46 relatives on letter fluency, but otherwise their performance was similar to that of nonschizotypal relatives. These data suggest that close relatives of schizophrenic patients may have subtle neuropsychological impairments that are not necessarily associated with clinical symptoms of schizophrenia spectrum disorders

Visuospatial working memory in schizotypal personality disorder patients

Background: Cognitive processing deficits have been identified as an abnormality that schizotypal personality disorder (SPD) individuals share with schizophrenic patients. It has been hypothesized that impaired working memory may be a critical component of several of the more complex cognitive deficits found in schizophrenia spectrum patients. Method: 18 DSM-III-R SPD patients, and 17 normal comparison subjects were compared on a pen and paper visuospatial working memory task. Moreover, we identified a second psychiatric comparison group comprised of nine patients with other, non-odd cluster personality disorder diagnoses who met no more than one of the SPD criteria and were also tested on the same task. Each person was given 14 immediate recall trials and 10 trials using a 10 s delay. Results: SPD patients performed significantly worse than normal control subjects on the working memory task. SPD patients also performed significantly worse compared to the non-schizophrenia-related personality disorder psychiatric comparison group. Conclusions: Like schizophrenic patients, SPD patients demonstrate working memory impairment compared to normal controls. This impairment may be specific to the schizophrenia-related personality disorders

Cognitive function and biological correlates of cognitive performance in schizotypal personality disorder

There is evidence that some schizophrenic patients have deficits on tests of cognitive function, particularly tests of executive function, including the Wisconsin Card Sorting Test (WCST) and the Trail-making Test, Part B. This study was conducted to determine the generalizability of these findings across the schizophrenia spectrum to schizotypal personality disorder (SPD). Forty DSM-III SPD patients, 56 nonschizophrenia-related other personality disorder (OPD) patients, and 32 normal volunteers from two medical centers performed tests of executive function such as the WCST, Trail-making Part B, Stroop Word-Color Test, and Verbal Fluency, as well as tests of more general intellectual functioning such as the Wechsler Intelligence Scale-Revised Vocabulary and Block Design subtests, and Trail-making Part A. SPD patients performed more poorly on the WCST and on Trail-making Part B than did OPD patients or normal subjects; the groups did not differ on tests of general intellectual functioning. SPD patients may share some of the cognitive deficits observed in schizophrenia