PubMed Health⌕ Search

Biomedical subjects

A L Orbeck

Publications and source records attributed to A L Orbeck.

6 recordsLinked to original sources
PubMed1997

Stability in cognitive dysfunctions in schizophrenic patients.

The purpose of the present study was to classify cognitive dysfunctions in schizophrenic subjects according to a trait/state model. A sample of 15 patients was examined on 10 different cognitive measures in two distinctly different phases: an acute psychotic state and partial remission. To determine the degree of dysfunction at the two stages of illness, the schizophrenic patients were also compared to 14 non-psychiatric controls. Six of the 10 measures examined can be classified as cognitive deficits in schizophrenics. Four measures are possibly trait-dependent components: two backward masking scores and two long-term memory measures. A short-term memory measure is the only one that can be classified as an episode-linked factor. The other cognitive deficits found can be characterized as mediating vulnerability factors, i.e. they are more prominent in the acute psychotic state, but do not completely disappear during remission states.

Adolescent↗
PubMed1994

Mueller-Lyer illusion and size estimation performance in schizophrenics compared to normal controls.

A size estimation (SE) paradigm and the Mueller-Lyer (ML) illusion were used to examine perceptual disturbances in schizophrenics. 35 reliably diagnosed (DSM III-R) schizophrenics were compared to 20 subjects with no history of psychiatric illness. Perceptual distortions found in previous studies of schizophrenics were only to a certain extent confirmed in the present results. More overestimators were found among the schizophrenics than among the normals on the SE task. The schizophrenics, first of all the chronic patients, also proved to be more prone to the Mueller-Lyer illusion. A reason why the very clear differences between schizophrenics and normals found in previous examinations were not confirmed in the present study, might be that a reliable diagnostic instrument was for the first time used in this kind of study.

Adult↗
PubMed1993

Memory functioning in chronic and non-chronic schizophrenics, affectively disturbed patients and normal controls.

Memory impairment has been reported among schizophrenics in several studies. There are a number of uncertainties in interpreting such deficits. The present study examined short- and long-term verbal memory in schizophrenic patients (n = 30), affectively distributed patients (n = 18) and normal controls (n = 18). Schizophrenics showed a significant decrease in memory test performance, compared with both normal controls and other psychiatric patients. Chronic schizophrenics seem to be characterized by qualitatively different memory functioning compared with non-chronic subjects. In a free recall task chronic subjects showed significantly decreased performance for the initial (primacy) and final (recency) items. Memory functioning was not correlated with performance on the Wisconsin Card Sorting Test. This could indicate a selective cognitive dysfunction of an amnesic nature in chronic schizophrenics.

Adult↗
PubMed1993

Stability in backward masking performance in schizophrenics, affectively disturbed patients, and normal subjects.

The purpose of the present longitudinal study was to investigate the stability of backward masking performance in schizophrenics and nonschizophrenic psychotic patients. Twenty-two schizophrenics, eight nonschizophrenics, and 14 normal controls were tested three times, with an interval of 1 year between each test session. A standard stimulus duration procedure was used. The relative onset intervals between the target and the mask was 16.5 msec or 33 msec. A no mask condition was presented before the two masking conditions. Results showed that masking performance is a stable phenomenon, for both psychiatric groups and for normal controls. Significant differences were found between schizophrenics and the normal controls, but not between the two psychiatric groups. Vulnerability to masking stimuli as a specific characteristic for schizophrenics is, thus, not supported in the present study. The results suggest that backward masking deficit is an enduring feature of psychotic disturbances.

Adult↗
PubMed1992

Vigilance deficits in schizophrenics and affectively disturbed patients.

Vigilance is a concept associated with the early levels of information processing. Vigilance deficits have repeatedly been found in schizophrenic patients. It has not been clear, however, whether such cognitive dysfunctions are specific to schizophrenics or not. In this study, 28 schizophrenics were compared with 19 affectively disturbed patients and 17 normals on a vigilance test that is a hybridization of a Continuous Performance Test (CPT) and a Span of Apprehension Test (SAT). The results showed that schizophrenics performed significantly below the normals only on target hits on the CPT. There were no differences between the two patient groups, either on number of correct hits or on commission errors. On the SAT measures, normals performed better than the two psychiatric groups on all measures. Schizophrenics had more commission errors than the affectives, but there were no differences between the two groups with respect to target hits. Neither CPT nor SAT deficit, thus, seem to be specific schizophrenic characteristics.

Adult↗