Comparison of the Transient Evoked Otoacoustic Emissions (TEOAEs) and Distortion Products Otoacoustic Emissions (DPOAEs) in Normal Hearing Subjects With and Without Tinnitus.

The aim of this study was to investigate the possible role of cochlear outer hair cell function with TEOAE and DPOAE tests in patients with normal hearing and tinnitus. 25 tinnitus patients with normal hearing sensitivity selected as study group. Control group consist of 50 normal hearing subjects without tinnitus. All subjects had thresholds below 25 dBHL at frequencies 250-8,000 Hz, tympanogram type A and normal acoustic reflex thresholds. TEOAE were recorded with click stimulus at 80 dB SPL at 1,000, 2,000, 3,000 and 4000 Hz. DPOAE were measured at frequencies 1,000-8,000 Hz and intensity of L1 55 dB SPL and L2 65 dB SPL. Amplitude of DPOAE and TEOAE were decreased in all frequencies in study group. There was significant difference regarding prevalence abnormal TEOAE and DPOAE between study group and control group. There was relationship between dysfunction of outer hair cells and tinnitus in subjects with normal hearing.