Disposition

Destroy this report when no longer needed. Do not return:t to the originator. USAMRL Report Ho. DA Project No. 3A01 OBJECTIVE To determine the relationship between the frequency of temporary threshold shift (TTS), the pitch of Induced tinnitus (IT), and the fre-quency of the inducing stimulus. METHOD Observers were exposed monaurally to four pure tones, to white noise, and to three octave bands of noise at levels sufficient to Induce tinnitus. They were asked to match the frequency of the tinnitus by manipulating the frequency of a tone in the opposite ear, and their TTS was then measured on a Bekesy audiometer. SUMMARY Both frequency of maximum TTS and pitch of induced tinnitus increased with frequency of the inducing stimulus; however « they did not coincide. CONCLUSION One should be hesitant in assuming that when an individual has a tinnitus of a certain frequency that his maximum hearing loss is at that frequency. ACKNQHLEÜGMENT