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

Evaluation of attentional and neuromotor functions in 45 patients meeting the Research Diagnostic Criteria for schizophrenia, schizoaffective disorder, and other affective disorders showed that schizoaffectives could not be distinguished from patients with other affective disorders by any of the measures. However, schizophrenics differed from the other diagnostic groups on four measures: they showed significantly more oculomotor, stereognosis, and right-left identification abnormalities and more errors of omission on the attentional task under distraction conditions. The findings of this study are consistent with earlier reports that schizoaffectives are not generally different from patients with other affective disorders in family history, treatment response, or long-term outcome. There is not yet sufficient etiologic or behavioral evidence to indicate that schizoaffective disorder is a valid diagnostic category.
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PMID:Attentional and neuromotor functions of schizophrenics, schizoaffectives, and patients with other affective disorders. 731 79

To investigate the relationship between behavioral and cortical measures of impaired attention in schizophrenia, 17 hospitalized acute schizophrenics and 16 hospitalized nonpsychotic patients were studied. Event-related potentials (ERP) were obtained while subjects performed the Continuous Performance Test (CPT) under three conditions: First base line, Auditory-Visual Distraction, and Second base line. Schizophrenics made more errors of omission and commission and had longer reaction times. Analysis of the Late Positive Component (LPC) of the ERP revealed that both groups had an attenuated LPC during distraction and a larger LPC to the critical compared to the noncritical stimulus throughout all conditions. Schizophrenics had a smaller LPC and a smaller amplitude difference between the critical and noncritical stimulus than the nonpsychotics throughout all conditions.
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PMID:The late positive component of the evoked response in acute schizophrenics during a test of sustained attention. 735 59

This study examined the effects of neuroleptic medication on the allocation of attentional resources to distracting stimuli in patients with schizophrenia. Twenty-five patients were tested twice (medication-free and after medication stabilization) on the Identical Pairs versions of the Continuous Performance Test under both distraction and no-distraction conditions. Sixteen patients were chronically ill adults and nine patients were young neuroleptic-native patients in the early stages of illness. Results indicated that neuroleptic treatment did not improve distractibility for either group and that both groups were comparably distractible. These findings suggest that medication does not improve the misallocation of attention to distracting stimuli in patients with schizophrenia.
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PMID:Distractibility in schizophrenia. 748 Mar 80

To further explore the hypothesis that schizophrenics are more distractable and/or have reduced processing resources available, event-related potentials (ERPs) and smooth pursuit eye movements (SPEM) were investigated in 20 medicated schizophrenics, 19 detoxified chronic alcoholics, and in a control group of 20 healthy subjects. Groups were matched for age and education. Eye tracking tasks and auditory oddball tasks were performed separately as well as simultaneously. In addition, an eye tracking condition with a task-irrelevant tone sequence was used to assess the effect of distraction. Schizophrenics showed a trend for poorer SPEM performance; alcoholics had no dysfunction in this task. Tracking accuracy did not change in either group when additional auditory stimuli were presented. P300 latency was delayed in both schizophrenics and alcoholics. P300 amplitude showed no overall group difference but it increased during the dual task in normals whereas it remained constant in patients. N100 amplitude was generally larger during the more complex conditions indicating heightened unspecific arousal. It is suggested that normals use increased arousal to mobilize additional resources and to allocate them to stimulus evaluation but schizophrenics and alcoholics are unable to do so. Results are more conform to a limited resources concept than to a filter deficit model of cognitive disturbances in schizophrenia and alcoholism.
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PMID:Information processing during eye tracking as revealed by event-related potentials in schizophrenics, alcoholics, and healthy controls. 757 68

Competing hypotheses that explain the effects of emotionally arousing, extraneous auditory stimuli on the social cue perception of schizophrenic patients were examined in this study: (1) extraneous arousing stimuli enhance patients' cue perception; (2) extraneous stimuli distract patients, and cue perception is diminished. Twenty-five patients with DSM-III-R diagnoses of schizophrenia completed a cue-perception task in which half of the videotaped vignettes included in the task were presented with simultaneous extraneous stimuli and half were not. Item difficulty and consistency across extraneous stimuli conditions were matched on standardization and cross-validation samples. Results showed that schizophrenic subjects were significantly more sensitive to cues when exposed to extraneous stimuli, thereby supporting the first hypothesis. This effect was also observed in a subgroup of schizophrenic subjects who demonstrated a distraction decrement on another test of short-term recall. The presence of extraneous stimuli interacted with perception of abstract cues; that is, schizophrenic subjects were particularly better at perceiving abstract cues when extraneous stimuli were presented simultaneously. Future research needs to determine characteristics of extraneous stimuli that enhance cue perception.
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PMID:Effects of extraneous stimuli on social cue perception in schizophrenia. 766 36

Thirty-five schizophrenic patients in the early stages of illness, 26 of their healthy siblings, and 35 normal control subjects performed the Continuous Performance Test, Identical Pairs version (CPT-IP). Both schizophrenic patients and their siblings were significantly impaired in their attentional performance compared with normal subjects. These results support impaired attention as a vulnerability marker of schizophrenia and indicate that at-risk siblings of schizophrenic patients display attentional deficits comparable to those found for the offspring of schizophrenic parents. By contrast, a decline in performance with the onset of a distraction condition (auditory and visual stimuli) was seen only in schizophrenic patients; siblings and normal control subjects did not differ from one another in response to experimental distraction. Therefore, it was concluded that differential distractibility is likely to be a state marker of schizophrenia. In clinical assessments, healthy siblings rated themselves as experiencing significantly more physical anhedonia than did normal control subjects, but the siblings did not differ from normal control subjects in self-rated perceptual aberrations. Contrary to expectation, performance on the CPT-IP did not correlate significantly with either anhedonia or perceptual aberration in high-risk siblings. These results suggest that psychometrically measured "psychosis proneness" and neuropsychologically detected deficits may tap two nonoverlapping sources of vulnerability to schizophrenia.
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PMID:Attentional abilities and measures of schizotypy: their variation and covariation in schizophrenic patients, their siblings, and normal control subjects. 779 30

We reviewed potential neuropsychological risk indicators for schizophrenia by addressing two broad questions about neuropsychological performance in biological relatives of schizophrenia patients: (1) Is there evidence of deficits, and, if so, (2) are those deficits similar to deficits found in schizophrenia patients themselves? There has not yet been adequate validation of most neuropsychological risk indicators, but promising leads have emerged from studies of relatives of persons with schizophrenia. The strongest evidence of impairment in relatives was in sustained attention, perceptual-motor speed, and concept formation and abstraction; to a slightly lesser extent, mental control/encoding (primarily with distraction) was implicated as well. Impairments in verbal memory and verbal fluency were also found, although these have been less well studied. The pattern of deficits paralleled that found in schizophrenia patients, thus suggesting dysfunction in prefrontal, temporal-limbic, and attentional systems. Findings were similar for children and adult relatives of schizophrenia patients. It is suggested that future studies (1) emphasize comprehensive test batteries, (2) develop composite neuropsychological measures, (3) use profile and deviant-responder analyses, (4) include psychiatric comparison groups, and (5) integrate neuropsychological assessments with brain imaging techniques.
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PMID:Neuropsychological risk indicators for schizophrenia: a review of family studies. 819 9

Distractibility and temporal modulation of attention in schizophrenics were studied using a visual reaction time task with additional auditory probe stimuli during the forewarning period or between trials. The probes were thought to exert a distracting influence, especially on schizophrenics, and at the same time they generated auditory EPs which allowed to track the modulation of cortical excitability during response preparation. The midline distribution of the terminal contingent negative variation (tCNV) and the amplitude of the postimperative negative variation (PINV) were clearly different in 20 DSM III-R schizophrenics, as compared with 20 alcoholics and 20 normal controls. In schizophrenics, the more frontal distribution of the tCNV was associated with a higher degree of psychopathology (measured with the Brief Psychiatric Rating Scale) and with delayed reactions. Probes between trials reduced tCNV and PINV in all subjects alike. However, this effect could not be attributed to distraction, because reaction times were faster in these trials, possibly due to an alerting effect of the auditory probes. The N100 and P300 amplitudes to probes in the forewarning period, i.e., during the negative potential shift of the CNV, were significantly enhanced in all groups. Apparently there is a state of increased cortical excitability during the CNV which is not selectively "tuned" toward relevant stimuli. In schizophrenia, the temporal and topographical regulation of this excitability is disturbed.
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PMID:CNV, PINV and probe-evoked potentials in schizophrenics. 859 73

Twenty-five normal subjects were tested in a Conditioning-Testing (S1-S2) auditory P50 study. Each subject was tested twice under two experimental conditions: distraction condition (with light interference) and control condition (without interference). Results showed that S1 P50 amplitude was significantly decreased with visual interference compared with that in the control condition, while the S2 response remained unchanged. Consequently, the S2/S1 gating ratio was also increased remarkably in the distraction condition. The auditory EP changes with the visual distraction in normals closely resembled the abnormal findings in schizophrenic subjects. These data may provide an alternative model to elucidate the psychophysiological mechanism that possibly rules the changes of attention in schizophrenia.
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PMID:P50 changes with visual interference in normal subjects: a sensory distraction model for schizophrenia. 882 78

Visually-guided saccades of 21 offspring of schizophrenic parents and 21 individually matched controls were compared with regard to the frequency of occurrence of saccadic hypometria and hypermetria, non-fixations, and omissions of target jumps. Target steps ranged from 10 to 60 degrees, and interstimulus intervals averaged 2.5 s; subjects were promised financial reward depending on performance. Recordings were carried out at the subjects' homes. To screen for cognitive abilities and psychopathological behavior, subjects were tested by means of an intelligence scale and a behavioral checklist. With large target steps (40-60 degrees), the high-risk group made significantly more grossly hypometric saccades (gain < or = 0.8) than the control group; responses to small target steps (10-30 degrees) exhibited a similar, albeit statistically not significant, trend. There were no significant differences with regard to the occurrence of hypermetria. Non-fixations scored marginally higher in the high-risks as compared to controls, but this was again not a significant difference. The incidence of omissions of saccades was very low in both groups. The results of the study suggest that subjects at genetic risk for schizophrenia may differ from controls by an increased incidence of conspicuously hypometric saccades. Clearly, this difference is not caused by a deficit of the saccadic motor circuitry proper; comparison to control data obtained with a similar experimental protocol suggests that it probably reflects an impaired internal control of saccades in the presence of distraction and stress. The relevance of saccades as indicators of a possible schizophrenic vulnerability is discussed.
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PMID:Visually-guided saccadic eye movements in adolescents at genetic risk for schizophrenia. 918 8


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