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Biomedical subjects

J A Cegalis

Publications and source records attributed to J A Cegalis.

11 recordsLinked to original sources
PubMed1983

What is deviant about deviant smooth pursuit eye movements in schizophrenia?

Smooth pursuit eye movements of schizophrenic, hospitalized nonpsychotic, and normal control subjects (18 per group) were measured in low and high target information conditions. A computer method for measuring saccade frequency and velocity was used. The results indicated that the frequency of saccades was significantly greater in both tracking conditions for schizophrenic than for hospitalized nonpsychotic or normal subjects. Consistent with our earlier finding, the reduction in saccade frequency with high information was greatest for schizophrenic subjects. The results also yielded a unique finding: the velocity of saccades within smooth pursuit records was significantly greater for schizophrenic than for hospitalized nonpsychotic or normal subjects. Greater saccade velocity was not a result of increased saccade size; there was no significant difference in the size of saccades for normal and schizophrenic subjects. Yet, the duration of saccades was significantly less for schizophrenics than for other subjects. Target information affected the frequency, duration and size, yet not the velocity of saccades emitted by all subjects. In contrast to earlier interpretations of deviant smooth pursuit eye movements in schizophrenia, the results may provide the first evidence of differences in the functioning of the saccadic eye movement systems of schizophrenic and normal subjects.

Adult↗
PubMed1982

Refixation saccades and attention in schizophrenia.

Saccadic refixation eye movements of 20 schizophrenic, 20 hospitalized nonpsychotic, and 20 normal subjects were compared in two repetitive fixation tasks with high and low target information. Although no differences emerged among groups in the overall frequency or size of saccades, the average and peak velocity of saccades was slower for schizophrenics than for normals. The velocity of saccades for the hospitalized nonpsychotic group was between that of schizophrenics and normals. To evaluate this finding further, saccades in the first two stimulus cycles were examined. The average and peak velocity of saccades was found to be significantly slower for schizophrenics than for normals. Again, the velocity of saccades for hospitalized nonpsychotic subjects was between that of schizophrenics and normals. Moreover, the size of saccades during the first two cycles was smaller for the schizophrenic than for other subject groups. Embedded alphanumeric information in the fixation target generally resulted in increased velocity of saccades for all subjects. The results were interpreted as evidence for an attentional deficit in schizophrenia. Specifically, schizophrenic subjects appeared to be less able to utilize peripheral visual information than hospitalized or normal subjects.

Adolescent↗
PubMed1981

Attention in schizophrenia. Signal detection in the visual periphery.

Earlier evidence has suggested a differential deficit in visual preattentive processes in schizophrenia. An understanding of the level of information processing at which such deficits might occur and links to a possible structural basis for such deficits were sought in an investigation of signal detection in the visual periphery. Acute and chronic schizophrenics alternatively classified as paranoid or nonparanoid and normals were tested in a task requiring simultaneous discrimination of foveal targets as well as detection of peripheral targets at either of two display angles where the use of scanning eye or head movements was experimentally controlled. An analysis of peripheral sensitivity indicated that chronic and particularly nonparanoid subjects were less able to detect peripheral targets than acute or paranoid schizophrenics and normals. An analysis of criterion indicated that paranoid subjects tended to be more conservative in the most difficult detection condition. Corresponding analyses of trial validity and response latency yielded no results indicative of systematic differences in motivation. Differences in sensitivity were therefore attributed to a deficit in early preattentive processes. The performance of nonparanoids also raised the question of differences in midbrain activity associated with the processing of ambient visual information.

Attention↗
PubMed1980

Visual selectivity in schizophrenia.

Further information concerning the nature of selective attention processes in schizophrenia was sought by examining selectivity in the region corresponding to the normal stationary visual field. Acute schizophrenic, chronic schizophrenic, and neurotic subjects were required to discriminate pairs of vertical columns of dots that varied in confusion value and in display angle. The results indicated that chronic subjects were only able to process low confusion peripheral stimuli within a narrow display angle of 12 degrees. Accurate discrimination of high confusion stimuli was limited among chronics to a display angle of 2 degrees. Acute schizophrenics were able to discriminate peripheral stimuli to 25 degrees. Although the performance of neurotic subjects was significantly better than that of chronic subjects, accurate discrimination of high confusion stimuli for neurotic subjects was limited to a display angle of 12 degrees. Differences in performance topography were attributed to the use of different selective strategies. The spatial extensity within which more efficient grouping strategies were used was apparently constricted for chronic schizophrenics and extended for acute schizophrenics relative to neurotic controls.

Adolescent↗
PubMed1979

Eye movements in schizophrenia: a quantitative analysis.

A quantitative comparison of smooth pursuit eye movements of acute and chronic schizophrenics was made. Horizontal, vertical, diagonal, and pendulum tracking targets with constant or variable velocity were presented. The frequency of saccades as well as the magnitude of the spatial and temporal error during tracking was significantly greater among schizophrenics than among normals. Yet the differences between acutes and chronics were not generally significant. Performance differences were generally unaffected by the type of stimulus. The frequency of nontracked half-cycles and eye blinks was greater for chronics than for acutes or normals, and greater for acutes than normals, suggesting that sustained voluntary attention was more difficult for schizophrenics in general and chronic schizophrenics in particular. A distinctive pattern of saccade bursts was observed in the fixation and tracking records of schizophrenic subjects. These bursts were suggestive of an oculomotor deficit.

Acute Disease↗
PubMed1977

Individual differences in responses to induced perceptual conflict.

Examining reactions to experimentally induced perceptual conflict may be a useful method of studying perceptual/cognitive disorganization and adaptive features of personality. Changes in field-dependence (rod-and frame test) were assessed in introverted and extraverted subjects (17-19 yr.) who were exposed to inversion of the visual field. Tolerance of ambiguity was also assessed. There were no significant differences between introverts (n = 20) and extraverts (n = 16) on preinversion measures of field-dependence. However, extraverts became more field-dependent on first exposure to inversion and maintained a generally higher level of field-dependence. Introverts became more field-dependent only after walking in the inverted visual condition and after a major change in exposure conditions. No significant differences in post-inversion levels of field-dependence were observed.

Adolescent↗
PubMedDate not supplied

Carbamazepine and psychotherapy in the treatment of schizoaffective psychosis.

The authors describe the interactions between and the differential effects of carbamazepine and individual psychotherapy in the treatment of a schizoaffective patient. Carbamazepine's impact on the patient's affective life facilitated the establishment of a working alliance in psychotherapy. As the patient began to understand and differentiate aspects of his affective, cognitive, bodily, and interpersonal experiences, his life situation stabilized and his carbamazepine dose requirements diminished.

Adult↗