Monaural loudness adaption at low sensation levels in normal and impaired ears.

Abstract

Monaural loudness adaptation was measured in subjects with normal hearing and in subjects with noise-induced sensori-neural hearing loss using a dichotic delayed balance procedure. Adapting stimuli were presented at two sensation levels (15 and 25 dB SL), two frequencies (500 and 4000 Hz), three durations (1, 30, and 60 sec) and two inter-stimulus intervals (10 and 400 msec) and the loudness of the terminal portion of the adapting stimuli was measured with a method of constant stimuli. No loudness adaptation occurred under any conditions for the normal subjects. Hearing-impaired subjects demonstrated small amounts of loudness adaptation, but the occurrence of adaptation did not always coincide with the frequency region of the hearing loss. There was no effect of interstimulus interval for either subject group. Subject Classification: [43]65.50, [43]65.64, [43]65.66.