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Biomedical subjects

R Klorman

Publications and source records attributed to R Klorman.

53 records · Page 3Linked to original sources
PubMed1980

Relationships between stimulus intensity and amplitude of visual and auditory event related potentials.

Event related potentials were recorded from subjects presented with separate trains of lights and tones of three intensity levels (75, 240 and 750 fl and 60, 77 and 95 dB respectively). The auditory P1-N1 and N1-P2 components increased linearly with loudness, whereas in visual evoked responses, these components were maximal at an intermediate brightness. There was no correlation between responses to the two modalities. The results are examined in relation to current theories of cortical stimulus processing.

Adult↗
PubMed1980

The late positive component of the evoked response in acute schizophrenics during a test of sustained attention.

To investigate the relationship between behavioral and cortical measures of impaired attention in schizophrenia, 17 hospitalized acute schizophrenics and 16 hospitalized nonpsychotic patients were studied. Event-related potentials (ERP) were obtained while subjects performed the Continuous Performance Test (CPT) under three conditions: First base line, Auditory-Visual Distraction, and Second base line. Schizophrenics made more errors of omission and commission and had longer reaction times. Analysis of the Late Positive Component (LPC) of the ERP revealed that both groups had an attenuated LPC during distraction and a larger LPC to the critical compared to the noncritical stimulus throughout all conditions. Schizophrenics had a smaller LPC and a smaller amplitude difference between the critical and noncritical stimulus than the nonpsychotics throughout all conditions.

Adolescent↗
PubMed1979

A further assessment of predictors of the child's behavior in dental treatment.

The child's disruptiveness during dental treatment was related modestly to his age as well as his state, trait, and dental anxiety. In three samples comprising 132 experienced and 49 inexperienced pedodontic patients, the child's behavior during treatment could not be predicted from any aspect of maternal anxiety -- trait, state, or dental. Previous conceptions of maternal influence on the child's dental anxiety should be re-evaluated.

Anxiety↗
PubMed1978

The effect of distraction on acute schizophrenics' visual tracking.

To examine the nature of impaired smooth pursuit eye movement (SPEM) in schizophrenia, 16 hospitalized schizophrenics in the acute phase and 16 hospitalized nonpsychotic patients were studied. The experiment consisted of five 30-sec visual tracking phases: (i) base line (no distraction); (ii) auditory-visual distraction; (iii) middle base line; (iv) dichotic listening; and (v) final base line. Schizophrenics were characterized by significantly more velocity arrests throughout all phases of the experiment. Auditory-visual distraction did not impair either group's SPEM relative to base line performance. In contrast, dichotic listening significantly increased both groups' velocity arrests. This form of distraction also tended to produce greater impairment among schizophrenics. The failure of apparently intense auditory-visual distraction to significantly disrupt schizophrenics' SPEM suggests that inattentiveness alone does not account for schizophrenics' tracking impairment. This notion is supported by the finding that only the more intense distraction by dichotic listening produced a (trend toward) greater impairment in schizophrenics.

Acoustic Stimulation↗
PubMed1975

Effects of warning-signal duration on the early and late components of the contingent negative variation.

Slow EEG potentials were recorded from three sites on the scalp (Fz, Cz and Pz) during a simple reaction time task in which the duration of the warning signal was either 0.5 or 2 sec. The duration of the foreperiod was held constant, and order of conditions was varied according to a latin square design. As predicted, the longer warning signal evoked increased amplitude of the early component of the contingent negative variation (CNV). These results confirm the interpretation of that wave as an orienting response. In contrast, the duration of the warning signal did not affect the second CNV component or reaction time latency. Additional dissociation between the two CNV components was evident in their distribution on the scalp. The early component was smallest at Pz, whereas the late component attained its lowest amplitude at Fz. Concurrently recorded palmar skin potentials exhibited different polarity and latency from the CNV.

Acoustic Stimulation↗