Clinical Application of Continuous Threshold Recording

Abstract

Continuous threshold for a pure tone (2000 cps) was recorded in 93 normal individuals and in 355 patients with impaired hearing. In normal individuals, no threshold rise above 10 db was recorded. In pure conductive deafness the threshold also remained constant. Among patients with otosclerosis a few showed more pronounced tone decay; in the majority the threshold was constant. About half of the patients with cochlear deafness showed no tone decay; in the other half a moderate tone decay was observed. In retrococh-lear deafness, pronounced tone decay was recorded in 85 %. Twelve patients with tumour of the cerebello-pontine angle all showed pronounced tone decay. Pronounced tone decay is considered to be indicative of functional impairment, not only of the acoustic nerve, but also of the central auditory pathways. As the test is simple to perform, it is of value in the topical diagnosis.