Differences of Auditory Epoked Potentials (AEPs) evoked by contralateral or ipsilateral monaural and binaural click stimuli
Uemura, Keiji The University of Tokushima
Edagawa, Koji The University of Tokushima
Okura, Masao The University of Tokushima
Ikuta, Takumi The University of Tokushima
Yoshimatsu, Makoto The University of Tokushima
auditory evoked potentials
monaural vs binaural
contralateral vs ipsilateral
Differences among AEPs evoked by left or right monaural, and binaural acoustic stimuli were studied with 40 healthy male subjects (21-33 y.o.). AEPs were evoked by click stimuli and derived from the five derivations and recorded averaging 100 responses, with 1024 msec of analysis time. The following results were obtained.
1) In all of five derivations, the contours of the group mean AEPs were roughly similar in both ipsilateral left and contralateral right monaural stimuli. These findings demonstrated that response characteristics in the cortex which contains receptive field of the two ears were well coincided with each other.
2) The latency of the N1 component was significantly shorter and the peak to peak amplitudes were significantly larger in both contralateral right monaural and binaural AEPs than in ipsilateral left monaural AEPs. These findings reconfirmed reports on both the hemispheric dominance of the contralateral ear and the stronger response of binaural stimuli than monaural stimuli.
3) The latency of the P2 component in contralateral right monaural AEPs was significantly longer than that in ipsilateral left monocular AEPs, and N 1-P 2, P 2-N 2 amplitudes were significantly larger. These findings supported the report that the sourse of P2 is the primary auditory area, and confirmed the hemispheric dominance of the contralateral ear.
4) The latencies of the long latency components in contralateral right monaural and binaural AEPs were significantly longer than those in ipsilateral left monaural AEPs, and their amplitudes were significantly larger. These findings suggested the existence of the complicated auditory imformation processing in the association cortex and long-recovery cycle system in the cortex.
Shikoku Acta Medica
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