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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We tested for a relationship between attention and genetic liability to schizophrenia. Samples of probands with DSM-IV schizophrenia (n=20), their well first-degree relatives (n=40) and healthy controls (n=82) were tested using measures of sustained attention (degraded-stimulus continuous performance test: DS-CPT) and selective attention (spatial negative priming task). Assuming a liability-threshold model, we predicted that probands would display greater attentional decrements than controls and that the relatives would show intermediate levels of decrement. We did not observe the predicted pattern of effect using either measure, although the probands showed a trend towards less negative priming. However, our results may have been affected by self-selection bias in probands and relatives and clinical heterogeneity among probands, which could have reduced our power to detect effects.
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PMID:Sustained and selective attention as measures of genetic liability to schizophrenia. 1129 79

The Penn Continuous Performance Test (PCPT), a measure of sustained visual attention developed for use in functional neuroimaging studies, was compared with a standard CPT developed by Gordon Diagnostic Systems (GDS; Vigilance subtest). The PCPT and the GDS CPT were administered with a standard neuropsychological battery to 68 healthy adults to assess reliability and construct validity. The test had adequate internal consistency, and convergent validity was established through significant correlations between measures of efficiency on the PCPT and the GDS CPT. With the exception of a significant correlation between efficiency measures on the GDS CPT and a measure of auditory sustained attention, neither version of the CPT correlated significantly with other measures in the battery. Factor analysis showed that the PCPT loaded with the GDS CPT. In 39 patients with schizophrenia and 39 matched, healthy controls, equivalent impairment was evident on the two CPT tasks. Neither version correlated significantly with symptom measurements. These results support previous conclusions that sustained visual attention in schizophrenia is a core information processing deficit, not directly related to symptomatology.
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PMID:Comparison of the continuous performance test with and without working memory demands in healthy controls and patients with schizophrenia. 1129 83

Prior research has demonstrated a reliable deficit in performance accuracy (e.g., d') on sustained-attention tasks in relation to psychometrically identified schizotypy and clinically diagnosed schizotypal psychopathology. The present study sought to expand the understanding of sustained-attention performance in relation to psychometric schizotypy through a study of reaction time (RT) performance. In this study, the author examined performance accuracy and RT on a high-load, sustained-attention task, the Continuous Performance Test-Identical Pairs (CPT-IP) version, in 31 high Perceptual Aberration Scale (PAS) and 26 normal control (control PAS) subjects from a large university population. High PAS (psychometric schizotypy) subjects displayed significantly longer RT performance on the CPT-IP relative to controls. The RT slowing was not explained by mental state or general intellectual ability factors. Contrary to expectation, a difference in performance accuracy (e.g., d') was not observed between the groups; however, power and other considerations cloud the interpretation of this finding. The meaning of the observed RT slowing is examined and its relation to current models of the development of schizophrenia is discussed.
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PMID:Reaction time slowing during high-load, sustained-attention task performance in relation to psychometrically identified schizotypy. 1135 23

Attentional abnormalities have long been known to characterize patients with schizophrenia. The data discussed in this report suggest that impaired attention (at least as measured by a specific task, the Continuous Performance Test, Identical Pairs (CPT-IP) version) may also be an endophenotype of particular promise for use in molecular genetic studies of schizophrenia. This conclusion is based on findings indicating that the deficits in verbal and spatial attentional processing tapped by the CPT-IP are heritable, developmentally stable, independent of clinical state, and predict future spectrum disorders in the at-risk offspring of parents with schizophrenia.
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PMID:Impaired attention as an endophenotype for molecular genetic studies of schizophrenia. 1142 79

Deficits in vigilance/sustained attention of schizophrenic subjects have been a main topic of neuropsychological schizophrenia research for many years. The degraded stimulus Continuous Performance Test (ds-CPT) is the standard paradigm for measuring vigilance. Measurement of vigilance requires the observation of the course of perceptual sensitivity over time. The present review shows that from a theoretical point of view it is possible to show vigilance deficits (as a decrease of sensitivity) with the ds-CPT if certain conditions are given. However, only in a few schizophrenia studies the course of sensitivity over time was evaluated, while in most studies merely the level of sensitivity was analysed. Results presented in this review suggest that level and course of sensitivity are largely independent variables. Vigilance can be operationalised adequately only when considering the course of sensitivity over time. Therefore there still is a considerable need for research on the meaning of vigilance deficits for manifestation, course and treatment of schizophrenia.
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PMID:[The vigilance paradigm in schizophrenia research - studies on the Continuous Performance Test (CPT)]. 1179 Nov 92

The Wisconsin Card Sorting Test (WCST), a test of concept formation, was given to 49 schizophrenia inpatients in three blocks of 64 cards each with the second block comprising special instructions and trial-by-trial feedback. With the help of a psychometric algorithm based on linear regression analysis, the patients were classified according to their response to these specific interventions. Results yielded 15 high scorers, 23 learners, and 11 nonlearners. This a priori classification was confirmed by cluster analysis. Next, these groups were further analyzed with the Degraded Stimulus Continuous Performance Test (DS-CPT), a test of target discrimination, and the Test of Attentional Style (TAS), which assesses habitual, subjectively experienced attentional problems. A significant difference between high scorers and nonlearners was found for discriminative sensitivity (d'), with the learners achieving intermediate scores. Results for only the DS-CPT response criterion (beta) and a TAS subscale (Distractibility) tended to be significant. Discriminant analysis also revealed that d' is the most powerful variable for discriminating among the subgroups. The article also addresses baseline versus dynamic assessment, specific rehabilitation needs in subgroups of schizophrenia patients different in learner status, and the neurocognitive characteristics of the subgroups.
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PMID:Attentional characteristics of schizophrenia patients differing in learning proficiency on the Wisconsin Card Sorting Test. 1182 94

This review puts into questions the possible role of cognitive vulnerability markers in prediction and prevention of schizophrenia. Until recently, none of the identified cognitive anomalies has been proved to be definitive. However, as new promising candidates are emerging (DS-CPT, CPT-IP, P suppression, Saccadic Eye Movements), the predictive value of these trait-type anomalies may be criticized regarding four issues, which are discussed: technical, metrological, theoretical, and clinical. As things stand, the existence of a cognitive vulnerability marker, which testify to a permanent pathological trait, does not constitute a sufficient factor to identify and treat subjects who are at risk for schizophrenia.
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PMID:Could cognitive vulnerability identify high-risk subjects for schizophrenia? 1245 82

Previously the NMDA (N-methyl-D-aspartate) receptor (NMDAR) antagonist ketamine was shown to disrupt generation of the auditory event-related potential (ERP) mismatch negativity (MMN) and the performance of an 'AX'-type continuous performance test (AX-CPT)--measures of auditory and visual context-dependent information processing--in a similar manner as observed in schizophrenia. This placebo-controlled study investigated effects of the 5-HT(2A) receptor agonist psilocybin on the same measures in 18 healthy volunteers. Psilocybin administration induced significant performance deficits in the AX-CPT, but failed to reduce MMN generation significantly. These results indirectly support evidence that deficient MMN generation in schizophrenia may be a relatively distinct manifestation of deficient NMDAR functioning. In contrast, secondary pharmacological effects shared by NMDAR antagonists and the 5-HT(2A) agonist (ie disruption of glutamatergic neurotransmission) may be the mechanism underlying impairments in AX-CPT performance observed during both psilocybin and ketamine administration. Comparable deficits in schizophrenia may result from independent dysfunctions of 5-HT(2A) and NMDAR-related neurotransmission.
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PMID:Effects of the 5-HT2A agonist psilocybin on mismatch negativity generation and AX-continuous performance task: implications for the neuropharmacology of cognitive deficits in schizophrenia. 1249 54

Impaired sustained attention seems to be a specific neuropsychological deficit that is closely linked to schizophrenia. Voxel based morphometry has emerged as a useful tool for the detection of subtle gray matter (GM) abnormalities. The aim of our study was to identify the cerebral regions related to the Identical-Pair version of the Continuous Performance Test (CPT-IP) performance in schizophrenic patients. The study included 13 right-handed, male, first-episode, paranoic, neuroleptic-naive schizophrenic patients and 13 matched controls. High-resolution whole-brain MR images were segmented and analyzed for the whole brain and for regions of interest (ROI) using SPM99. Furthermore, the correlation between CPT-IP performance and GM density was examined. Volumetric analysis of the thalami was also carried out. GM density analysis shown decreases in patients in anterior cingulate gyrus, left inferior frontal, right claustrum, left pulvinar, and dorsomedial bilateral thalamic nuclei, and caudate nuclei as well as left hippocampus and parahippocampal gyrus. Thalamic ROIs revealed a strong correlation between groups differences. The thalamic GM density allowed a good individual classification. GM increases were detected in left insula, superior temporal gyrus, and putamen nucleus, and right supramarginal gyrus. Schizophrenic patients showed smaller left and right thalamic volumes. We found that GM density of the left thalamic nucleus, left angular, and supramarginal gyrus, and left inferior frontal and postcentral gyri correlated significantly with CPT-IP performance in patients but not in controls. Moreover, the restricted ROIs regression was strongly significant for both left and right thalamus. In summary, we provide evidence for the involvement of thalamic, inferior-parietal, and frontal regions in the attentional deficits observed in schizophrenic patients.
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PMID:Sustained attention impairment correlates to gray matter decreases in first episode neuroleptic-naive schizophrenic patients. 1281 86

High density electrical mapping was used to index event-related brain activity in subjects performing parametric variations of the "AX"-type continuous performance task (AX-CPT) that differentially challenge control, and informative control conditions. In the AX-CPT, subjects must use context, created by a cue stimulus, to guide response to a target. Diseases such as schizophrenia and attention deficit hyperactivity disorder (ADHD) are associated with impaired AX-CPT performance. Event-related potentials (ERP) were analyzed as a function of both global and local stimulus context. The topographical analysis revealed that well-defined ERP are elicited under conditions where subjects must override a prepotent response. Activation patterns related to overriding a prepotent response (Go to No-Go) differed markedly from those associated with overriding a prepotent non-response (No-Go to Go). Dipole source mapping suggested that withholding a prepotent response is reflected primarily in anterior cingulate/dorsolateral prefrontal cortex activity during the 350-450 ms latency range following presentation of the No-Go. In contrast, preparing to respond is reflected in parietal (including area BA 40) activity during the same latency range, followed by a prolonged frontal negativity (contingent negative variation; CNV). Similar patterns of activation were observed whether the changes in preparation were triggered by cue or target stimuli, though target-elicited potentials peaked earlier.
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PMID:Changing plans: a high density electrical mapping study of cortical control. 1281 85


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