Effects of stimulation intensity, gender and handedness upon auditory evoked potentials

Camposano, Susana; Lolas, Fernando

doi:10.1590/S0004-282X1992000100008

Abstracts

Left handers and women show less anatomical brain asymmetry, larger corpus callosum and more bilateral representation of specific functions. Sensory and cognitive components of cortical auditory evoked potentials (AEF) have been shown to be asymmetric in right handed males and to be influenced by stimulus intensity. In this study the influence of sex, handedness and stimulus intensity upon AEP components is investigated under basal conditions of passive attention. 14 right handed males, 14 right handed females, 14 left handed males, and 14 left handed females were studied while lying awake and paying passive attention to auditory stimulation (series of 100 binaural clicks, duration 1 msec, rate 1/sec, at four intensities). Cz, C3 and C4 referenced to linked mastoids and right EOG were recorded. Analysis time was 400 msec, average evoked potentials were based on 100 clicks. Stimulus intensity and gender affect early sensory components (P1N1 and N1P2) at central leads, asymmetry is influenced only by handedness, right handers showing larger P1N1 amplitudes over the right hemisphere.

auditory evoked potential; sex difference; handedness difference

Los sujetos zurdos y de sexo femenino tienden a exhibir menores grados de asimetria anatómica, mayores diámetros del cuerpo calloso y mayor representación bilateral de funciones específicas. Los componentes sensoriales y cognitivos del potencial evocado auditivo (PEA) cortical han demostrado sensibilidad a la intensidad de estimulación y asimetría en sujetos masculinos. En este estudio se investiga la influencia de sexo, ma-nualidad e intensidad de la estimulación sobre los componentes corticales del PEA. 56 sujetos voluntarios fueron sometidos a estimulación auditiva (series de 100 clicks binaurales, duración de 1 mseg, frecuencia de 1/seg, a cuatro diferentes intensidades) instruyéndoseles a prestar atención pasiva. Se registró derivaciones Cz, C3 y C4 referidas a mastoides bilateral y electrooculograma derecho, el tiempo de análisis fue de 400 mseg, los promedios fueron obtenidos sobre 100 clicks. La intensidad de la estimulación y el sexo afectan los componentes sesoriales corticales P1N1 y N1P2 en la derivación central. La asimetria sólo es influenciada por la manualidad; los Ss diestros exhiben mayores amplitudes P1N1 en el hemisferio derecho.

potencial evocado auditivo; diferencia sexual; diferencia de manualidad

Susana Camposano; Fernando Lolas

Psychophysiology Unit, Department of Physiology and Biophysics, Faculty of Medicine, University of Chile. This research is supported by FONDECYT Project 1126/90, and the University of Chile (D.T.I.)

SUMMARY

Left handers and women show less anatomical brain asymmetry, larger corpus callosum and more bilateral representation of specific functions. Sensory and cognitive components of cortical auditory evoked potentials (AEF) have been shown to be asymmetric in right handed males and to be influenced by stimulus intensity. In this study the influence of sex, handedness and stimulus intensity upon AEP components is investigated under basal conditions of passive attention. 14 right handed males, 14 right handed females, 14 left handed males, and 14 left handed females were studied while lying awake and paying passive attention to auditory stimulation (series of 100 binaural clicks, duration 1 msec, rate 1/sec, at four intensities). Cz, C3 and C4 referenced to linked mastoids and right EOG were recorded. Analysis time was 400 msec, average evoked potentials were based on 100 clicks. Stimulus intensity and gender affect early sensory components (P1N1 and N1P2) at central leads, asymmetry is influenced only by handedness, right handers showing larger P1N1 amplitudes over the right hemisphere.

Key words: auditory evoked potential, sex difference, handedness difference.

RESÚMEN

Los sujetos zurdos y de sexo femenino tienden a exhibir menores grados de asimetria anatómica, mayores diámetros del cuerpo calloso y mayor representación bilateral de funciones específicas. Los componentes sensoriales y cognitivos del potencial evocado auditivo (PEA) cortical han demostrado sensibilidad a la intensidad de estimulación y asimetría en sujetos masculinos. En este estudio se investiga la influencia de sexo, ma-nualidad e intensidad de la estimulación sobre los componentes corticales del PEA. 56 sujetos voluntarios fueron sometidos a estimulación auditiva (series de 100 clicks binaurales, duración de 1 mseg, frecuencia de 1/seg, a cuatro diferentes intensidades) instruyéndoseles a prestar atención pasiva. Se registró derivaciones Cz, C3 y C4 referidas a mastoides bilateral y electrooculograma derecho, el tiempo de análisis fue de 400 mseg, los promedios fueron obtenidos sobre 100 clicks. La intensidad de la estimulación y el sexo afectan los componentes sesoriales corticales P1N1 y N1P2 en la derivación central. La asimetria sólo es influenciada por la manualidad; los Ss diestros exhiben mayores amplitudes P1N1 en el hemisferio derecho.

Palavras llave: potencial evocado auditivo, diferencia sexual, diferencia de manualidad.

Palavras chave: potencial evocado auditivo, diferença sexual, diferença manualidade.

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

Dr. Fernando Lolas Department of Physiology and Biophysics, Faculty of Medicine, University of Chile - P.O. Box 70005 - Santiago 7 - Chile.

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