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Biomedical subjects

K Rymar

Publications and source records attributed to K Rymar.

6 recordsLinked to original sources
PubMed1984

Correlations of event-related potentials with schizophrenic deficits in information processing and hemispheric dysfunction.

In order to obtain further insight into hemispheric dysfunction in schizophrenics, two experiments were conducted employing event-related potential (ERP) recording during dichotic detection tasks as well as syllable discrimination tasks. Results concerning ERPs derived from the T3 and T4 regions are reported. Based on results in the two experiments, it is concluded that schizophrenics display a dysfunction of the left hemisphere, as well as a dysfunction in the ingration mechanism of both hemispheres. It is also speculated that the left-hemisphere dysfunction in schizophrenics is particularly correlated with positive psychotic symptoms.

Adult↗
PubMed1984

Verbal memory disturbances in left temporal lobe epileptics.

The relationship between laterality of paroxysmal discharges and characteristics of disturbances in memory functioning was investigated in temporal lobe epileptics. Subjects consisted of 22 temporal lobe epileptic patients, in whom the foci of the paroxysmal discharges were localized to one side of the temporal regions. The left focus group consisted of 10 patients; the right focus group, 12. Subjects were required to recognize verbal material presented to one hemisphere by means of a tachistoscope. The left focus group alone failed to demonstrate a right visual field superiority in these tasks. It was concluded that the left focus group specifically demonstrate disturbances in verbal memory functioning, particularly when stimuli were presented to the left hemisphere. Paroxysmal discharges seemed to interfere with normal memory functioning in the region where the foci of these discharges were found.

Adult↗
PubMed1984

Hand and eye preference patterns in elementary and junior high school students.

There has been some controversy concerning the relationship between eye preference and hand preference. Another controversy involves age differences in eye preference patterns. These two issues were investigated in 725 elementary and junior high school students employing various tests. It was found that a sex difference exists in hand preference patterns. Males seem to display less right hand preference as compared to females; on the contrary, these was no sex difference in eye preference patterns. Hand preference was found to be negligibly correlated with eye preference. The distribution patterns of eye preference were reversed between right handers and left handers. Age difference were not observed in eye preference patterns.

Adolescent↗
PubMed1984

Assessment of P300 latencies for individual EEG responses employing an adaptive correlating filter.

Correlations between latencies of P300 components in evoked potentials and reaction times were investigated in two normal subjects. The subjects were required to perform choice reaction tasks, responding to particular tones among three tones with different frequencies. EEGs were recorded at the Pz region monopolarly. Latencies of P300 for individual EEG responses were measured employing an adaptive correlating filter. Cross-correlation coefficients between the second templates employed to identify P300s and individual responses for the subjects ranged from 0.623 to 0.997, with the mean value being 0.931. The correlation coefficient between latencies of P300 and reaction times for the subjects was 0.659. Thus, the adaptive correlating filter was proved to be useful in psychophysiological studies.

Adult↗
PubMed1984

Abnormalities in late positive components of event-related potentials may reflect a genetic predisposition to schizophrenia.

Event-related potentials (ERPs) were recorded at the Cz region during syllable discrimination tasks in siblings of schizophrenic probands. ERPs in these siblings were compared to those of normal controls and schizophrenics. Siblings, similar to normal controls, displayed an increase in amplitudes of N100 according to the allocation of their attention between two different channels (ears), Siblings different from normal controls, however, failed to demonstrate an augmentation of late positive components upon detection of target stimuli in the attended channel. Mean amplitudes of late positive components elicited by target stimuli in the attended channel for siblings were nearly equal to those of unmedicated schizophrenics, with these values in siblings being significantly smaller as compared to those of normal controls. Based on these results, it was concluded that abnormalities of late positive components in siblings may reflect a genetic predisposition to schizophrenia.

Adolescent↗