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Biomedical subjects

P B Vrtunski

Publications and source records attributed to P B Vrtunski.

9 recordsLinked to original sources
PubMed1991

Isometric force control in schizophrenic patients with tardive dyskinesia.

Force control (FC) function, considered to be a constituent component of motor output, was investigated in psychiatric patients with dyskinetic impairments. Twenty-one patients with mild-to-moderate tardive dyskinesia were compared to 25 nondyskinetic patients on an FC test for both hands and oromandibular region. Results indicate that FC impairment is readily observed in dyskinetic subjects. The FC steadiness (i.e., the ability to maintain a sustained force output) in dyskinetic and control subjects was found to be inversely proportional to the amount of force generated. This method provides an objective, simple, and precise quantification of motor impairment along a force-defined continuum. It may be useful in studying tardive dyskinesia and the effects of neuroleptic medication on motor output control.

Adult↗
PubMed1989

Voluntary movement dysfunction in schizophrenics.

Several aspects of fine motor control were compared in schizophrenics and two control populations. The motor behavior analyzed was a button-press response in a forced choice paradigm. Three areas of abnormality were seen in schizophrenics: first, the interval preceding the motor response was characterized by reduced motor steadiness prior to the button-press response; second, the motor response was made with excessive force (hyperdynamia); and third, the agonist-antagonist synchrony (motor reversal) was impaired. Schizophrenics on and off neuroleptics did not differ on any measure of motor control, but schizophrenics with clinically observed tardive dyskinesia were found to have significantly less steadiness prior to the motor response than other schizophrenics.

Adult↗
PubMed1986

Abnormalities of fine motor control in schizophrenia.

Response time and fine motor control during a classification task were examined in schizophrenics and nonschizophrenics. The task involved decisions about either the sensory characteristics of auditory and visual stimuli or the referential meanings of spoken words and viewed pictures. Nonschizophrenics responded more quickly and exhibited a smoother and faster motor response on all tasks. Response time and motor control were influenced by stimulus modality and the complexity of the classification task in both groups. In the analysis of motor control, the schizophrenics differed from the nonschizophrenics in exhibiting a pattern suggestive of a specific difficulty with decisions involving referential meaning. The observed motor control dysfunction in schizophrenics is a psychomotor deficit similar to previously reported abnormalities in smooth pursuit eye movement. Further, the interaction of group and task variables in the motor response suggests that decisions about the abstract referential meaning of words and pictures produce greater cognitive loads in schizophrenics than in nonschizophrenics.

Adult↗
PubMed1979

Evaluation of delayed auditory feedback (DAF) effect: comparison between subjective judgments and objective measures.

The effect of Delayed Auditory Feedback (DAF) on speech duration was evaluated subjectively and measured objectively in 30 subjects (10 normals, 10 nonfluent aphasics and 10 fluent aphasia). The average correlation coefficient between the subjective and objective data was .52 for 180 msec. delay and .46 for 360 msec. delay. Analysis of variance of data derived from the two methods showed the same highly significant differences among groups, delay and tasks. We conclude from these results that both objective and subjective procedures are equally useful in evaluating DAF effect on speech duration, and that both may also be valuable in assessing other types of behavior.

Aphasia↗
PubMed1978

Delayed auditory feedback and aphasia.

The effect of Delayed Auditory Feedback (DAF) was evaluated in three groups of subjects: 10 normal controls, 10 non-fluent aphasics, and 10 fluent aphasics. Speec production tasks consisted of (1) repeating sound and words; (2) naming objects; (3) producing sentences from given stimulus words; (4) answering questions; (5) reciting nursery rhymes; and (6) reading. Two delays were used, 180 and 360 msec. Two independent judges rated patients' responses for changes in intensity, duration, and quality of speech. Inter-judge reliability was considered satisfactory. Contrary to some previous reports, all subjects, including all the fluent aphasics, showed some DAF effect. Fluent aphasics, however, showed a significantly smaller DAF effect than non-fluent aphasics. Patient with conduction aphasia appeared to be the least impaired. Overall DAF effect was greater with 180 msec. than with 360 msec. The largest DAF effect occurred during answering question, followed by repeating, reading, nursery rhymes, sentence production, and naming, in that order. Repetition of a complex word produced a greater DAF effect than repetition of a simple sound. Finally, we found a differential effect of DAF on the three measures used in the study. We hypothesize that DAF effects result from changes in two separate monitoring systems. One systems is related to changes in the intensity of speech and does not appear to be affected by aphasia. The other is responsible for duration and qualitative changes in speech and is differentially affected in relation to pathology producing aphasia.

Adult↗
PubMed1977

Neuropsychological correlates of hypertension.

Twenty newly diagnosed, untreated hypertensive men (diastolic blood pressure greater than 105 mm Hg) and 20 normotensive controls were given a neuropsychological battery, including tests of generalized, more global functions (eg, reaction time and full-scale IQ) and of specific functions (eg, language and visual-spatial abilities) sensitive to focal damage. Tests of specific abilities yielded no differences between the two groups. In contrast, tests of general neuropsychological functioning revealed a deficit among hypertensives, who were significantly slower on the reaction time test and had a shorter span for digits in forward order. Results suggest that arterial hypertension is associated with impairment of vigilance and attention span. Future research will determine whether this impairment is associated with the diffuse pathological changes seen in the brain of hypertensive subjects, or with a more "functional" change (eg, reduced cerebral blood flow).

Attention↗
PubMed1976

Response to delayed auditory feedback in patients with hemispheric lesions.

The effect of delayed auditory feedback (DAF) on the performance of verbal and nonverbal tasks at two levels of difficulty by patients with left or right hemispheric lesions and non brain-damaged controls was compared. All subjects showed DAF effects, as measured by increases in response duration and intensity. While controls showed an increase in DAF effects as a function of increased task difficulty, the brain-damaged patients failed to show such an increase on tasks on which they were presumably impaired (verbal tasks for lefts, nonverbal for rights). Findings suggest a clear dissociation between DAF effects in unilateraly lesioned patients due to the nature of the stimulus material and its difficulty level.

Aphasia↗
PubMedDate not supplied

Information overload disrupts digit recall performance in schizophrenics.

The effect of auditory information overload on schizophrenics was examined by using a modified forward digit recall task. When memory capacity was exceeded, schizophrenics, but not controls, showed severe disruptions in performance on individual trials. Theories to account for the disruptions are discussed. A combination of factors, rather than simply limited information handling capacity, appears best able to account for the phenomenon. It is emphasized that further understanding of active cognitive process requires examination of trial by trial individual subject data.

Adult↗