Initial Auditory Adaptation I. In Normal Individuals

Abstract

The purpose of the present investigation was to elaborate an adaptation test for use in clinical routine and to establish normal values, so that the test could subsequently be applied in various forms of deafness. Seventy-four normal subjects of all ages were tested. The initial adaptation was measured by the threshold rise of a short tone (30 msec) applied 50 msec after the cessation of a pure-tone stimulus (1000 msec). The frequencies of the stimulus tones were 250, 1000 and 4000 cps. The frequency of the test tone was at all frequencies ½ octave above that of the stimulus tone. With this frequency interval the (threshold) shift was observed at stimulus intensities of 50–55 db above the hearing threshold at all frequencies, with increasing age at lower intensities. The threshold rise at intensities 20 db above incipient adaptation amounted to 12–14 db at all ages.