Normal i̇şi̇tme eşi̇ği̇ne sahi̇p ti̇nni̇tus hastalarin koklear i̇şi̇tsel fonksi̇yonlarinin odyoloji̇k değerlendi̇rmesi̇

Tinnitus is defined as the perception of sound that results completely from activity within the nervous system without any corresponding mechanical, vibratory activity within the cochlea, and not related to external stimulation of any kind. It is still difficult to explain pathophysiology mechanisms of tinnitus in patients with normal hearing ability. In this study we aimed to investigate mechanisms of tinnitus in patients with normal hearing ability based on inner and outer hair cells incompatible damage theories.The study group consisted of 30 tinnitus patients with normal hearing ability(49 tinnitus ears) and control group consisted of 25 people with normal hearing ability (49 normal ears). Both groups underwent basic audiological tests which include pure tone audiometry and tympanometry. The tests were then followed by TEOAE and DPOAEs measurements and the Thereshold Equalizing Noise(TEN )test. The study group was underwent tinnitus pitch and loudness matching test,and the patients were asked to fill the information form and take the Tinnitus Handicap Test. The present study found 19.04 % of tinnitus ears with abnormal TEOAEs and found 27.12 % of tinnitus ears with abnormal DPOAEs. The controls were observed to have only 5.26 % of the ears with abnormal TEOAEs and 20.12% of the ears with abnormal DPOAEs. The difference of TEOAE mean amplitüd between the two groups is significant at all frequencies except for frequency 4000Hz.The difference of DPOAE mean amplitüd between the two groups is only significant at frequency of 1400Hz. No one in the two group demonstrated an abnormal TEN test result.As aresult,inner hair cells and outer hair cell incompatible damage theory (discordant dysfunction) is confirmed. However, more researches need to be carried out in this area in order to support the current finding.