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Biomedical subjects

J Busk

Publications and source records attributed to J Busk.

5 recordsLinked to original sources
PubMed1979

Hemispheric dysfunction in schizophrenia: assessment by visual perception tasks.

Before and after a double-blind trial of haloperidol vs. mesoridazine, 24 hospitalized schizophrenics performed visual perception tasks designed to assess function of the cerebral hemispheres. Tasks involved identifying as "same" or "different" two images (either letters, digits, or unfamiliar shapes) projected tachistoscopically to the right or left visual field or to both together. Multivariate analysis of variance related response latency and accuracy to task type, hemisphere stimulated, and pre- vs. posttreatment testing. Both before and after treatment, subjects responded most slowly and least accurately to letter-matching. Bilateral presentation of stimuli resulted in faster and more accurate responses, except on shape-matching. Neuroleptic treatment improved speed and accuracy overall, though not under certain task conditions. Results accorded more with an impairment in verbal processing and interhemispheric coordination than with a specific left-hemispheric deficit in schizophrenia.

Acute Disease↗
PubMed1976

Therapists' physiological activation and patient difficulty.

The differential effects of an easy and difficult-to-interview patient on therapist self-reported behavioral arousal and physiological activation were observed. Eighteen experienced white male psychiatrists each interviewed two patient simulators believing they were real patients. Each actress was programed to act the part of a difficult-to-interview patient and an easy-to-interview patient. Each randomly played either part as assigned and the order of patient and role was counterbalanced. Differences in patient roles were validated by the participating therapists and independent raters. Fifteen-minute rest periods with soft music preceded each therapy session such that a complete experimental session consisted of rest 1, therapy 1, rest 2, and therapy 2. Self-reported arousal was assessed during each of the four periods by Thayer's factors from the Nowlis Mood Adjective List. Physiological activation was measured by electromyogram, heart rate, blood pressure (systolic and diastolic), and skin conductance. Therapist self-reported behavioral arousal and measured physiological activation during therapy were significantly greater than during rest. The difficulty of the patient did not appear to affect either behavioral or physiological activation level of the therapists. Several explanations for this are explored.

Arousal↗
PubMed1975

EEG correlates of visual-motor practice in man.

Special analysis of EEG signals was performed for 15 subjects engaged in three motor tasks of differing difficulty. A measure of average weighted coherence (C) was computed between the six possible combinations of four scalp areas: Oz, C3, C4 and Fz. In all subjects, regardless of task, scalp recordings over cortical areas known to have relatively dense fiber connections had significantly greater C values. However, the effects of task difficulty and practice were superimposed upon this basic pattern. Thus, the most difficult task (pursuit-rotor tracking) resulted in the highest coherence levels, while the least difficult task (visual tracking only of the pursuit-rotor disk) resulted in the lowest coherence levels. Practice, on the other hand, was associated with a significant decrease in overall level of coherence. This decrease is consistent with an interpretation of reduced task difficulty due to visual-motor learning. The results of the present study suggest that patterns of scalp EEG coherence may reflect some aspects of the underlying pattern of anatomical pathways, as well as the more dynamic properties of task difficulty and visual--motor practice.

Adolescent↗
PubMed1975

Effect of preconditioning visual stimulus duration on visual-evoked responses to a subsequent test flash in Down's syndrome and nonretarded individuals.

Visual-evoked responses to a visual test flash preceded by three different durations of a visual conditioning flash having the same intensity and form were recorded from 8 Down's syndrome subjects and 9 nonretarded CA-matched control subjects. Both groups showed a significant decrease in visual-evoked response perimeters to the test flash as the duration of the visual conditioning flash increased from 1 to 100 msec. For the 1000-msec condition, perimeters of Down's syndrome subjects showed a significant increase, and this was significantly greater than the nonretarded group. These results suggest that Down's syndrome individuals have deficits in their neural processing of sensory information.?23Author

Adolescent↗