Department of Oto-Rhino-Laryngology, Faculty of Medicine Schinshu University, Matsumoto

Abstract

Part I: Cochleopupillary response in awake stateThe author studied on the possibility of objective measurement of hearing by means of cochleopu-pillary response and obtained following results.To measure accurately. the threshold of this response, it was necessary to give the sufficient duration between each stimulus. In about 67% of normal hearing, the differences of threshold between pupillary response and subjective audiometry were 0 to 20db, while in the remaining 33%, threshold of the former was 30 to 80db above the latter. In advanced deafness, most of the pupillacy response arose near the subjective threshold. Technically it was difficult to observe the response to infants under 3 years old.These results indicate that the cochleopupillary response is not practically sufficient to apply as an objective audiometry, but is avaiable as a supplemental means of other methods.Part II: Cochleopupillary response in asleep stateThe author found that the cochleopupillary response also arose in asleep state, and confirmed that the measurement of hearing by means of this method was respectably avaiable as an objective audiometry. Though the preparative procedure may be slightly troublesome because of keeping in suitable sleep. the special apparatus is unnecessary and the observation of response is easy.On measurement, there was no age limit at least above 4 months old. In most of normal hearing, both infants and adults, the threshold of this response was 50 to 80db above subjective hearing level, but it was difficult to respond in deep sleep or general anesthesia.