Early diagnosis of vhith—nerve tumours by acoustic reflex tests

Abstract

Acoustic reflex tests were performed in 12 cases of tumour of the acoustic nerve and five tumours of the posterior fossa so located as to affect the nerve. The acoustic reflex threshold was pathologically elevated in all 17 cases, and in seven cases so much that the reflex could not be acoustically elicited. In the 10 cases in which the reflex threshold could be attained, the response showed an abnormally rapid fatigue on prolonged stimulation, a phenomenon here termed “reflex decay”. The observations indicate that the reflex—decay phenomenon is the earliest audiological sign of an incipient lesion to the acoustic nerve, and hence it is of great value in the early diagnosis of acoustic tumours.