難聴の指標としてのブライエル反射に関する実験的研究

抄録

The purpose of this investigation is to evaluate the Preyer's reflex or the acoustic-auricular reflex as hearing index. The Preyer's reflex responds to the sound stimulation from 300cps to 16000cps.
The measurable range is so restricted that the threshold curve of the reflex ranges from 75 to 110 phon and is between pseudothreshold curve and maximum threshold curve of the cochlear microphonics (CM). From electromyographic study, it has been demonstrated that the latency of the reflex is longer in lower frequencies and becomes shorter in response to the increased sound pressure. The various factors which may affect the latency of the reflex have also been investigated. The thresholds of the reflex were compared with those of the CM at various periods after Kanamycin (KM) injection in animals. These two thresholds show a similar pattern during the course of the experiments.
From these results, it is possible to conclude that the Preyer's reflex is useful not only to detect the high tone hearing loss in early stage but to detect when the CM is to be measured and also to obtain frequency pattern of hearing impairment in long periods of experimentations.
In KM-injected animals there appears frequently the abnormal adaptation of the pinna movement in which the amplitude of both the pinna movement and neuromuscular units in EMG gradually decreased in response to the sound stimulation below 8000cps. However, there is no similar findings demonstrated in the action potential and in the CM recorded from the round window.
The possibility of detecting the hearing impairement of the central origin by using this reflex is discussed.