A Threshold Tone Decay Test

Abstract

A new test has been used as a clinical aid in the topical diagnosis of impaired hearing.

A pure tone (2000 cps) was presented at threshold for 90 seconds unless it faded away before that time. In the latter case the intensity was increased by 5 db. The procedure was repeated until the tone was heard at one level for 90 seconds.

In normal individuals, the maximum tone decay was 10 db. In pure conductive hearing loss, the values were as in normal individuals. In cochlear deafness a more pronounced tone decay was measured in some cases; in others the test was normal. Excessive “relapse” was found only in retrocochlear deafness.

Pronounced threshold tone decay is considered to be indicative of functional impairment of the central auditory pathways or the acoustic nerve.