Comparison of otoacoustic emissions by frequency matching in tinnitus patients

Purpose: Tinnitus, is a common presenting symptom in otorhinolaryngology clinics. 65% of adults with hearing impairment report tinnitus as a concomitant symptom and 50% of them are severely affected from this condition. These data show us that tinnitus is a common symptom in general population and it is considered as important. In literature DPOAE amplitudes of tinnitus patients reported to be lower than control group. Furthermore it is documented to be a positive relationship between the frequency with the greatest amplitude decrease and tinnitus frequency subjectively determined by patients. Purpose of this study is to compare DPOAE amplitudes by frequency matching in tinnitus patients. Material and Method: 60 patients aged between 18 and 70 with normal hearing (pure tone mean ≤40 dB) and tinnitus who applied to Ege University Otorhinolaryngology clinic were included in this study. Pure tone audiometry test were performed in these individuals to determine their hearing thresholds. Patients with pure tone mean of pure tone mean ≤40 dB were considered to have normal hearing. In tinnitus patients with normal hearing thresholds frequency (Pitch Matching) and intensity (Pitch Loudness) of tinnitus were measured. DPOAE responses of the participants were recorded and statistically analyzed afterwards. Findings: A total of 60 individuals, 32 women and 28 men participated in this study. Mean age of participants was 44,22 ± 12,37 years ranging from age of 18 to 70. In cases with tinnitus frequency of 500 Hz there was a negative, moderate and statistically significant correlation between tinnitus severity and 500 Hz DPOAE amplitudes. In cases with tinnitus frequency of 4000 Hz there was a negative, weak and statistically significant correlation between tinnitus severity and 2000 Hz DPOAE amplitudes. No statistically significant correlation was found between the severity of the tinnitus and other variables. Results: In cases with tinnitus frequency of 500 Hz, DPOAE amplitude of 500 Hz were found to be lower. This suggests that there may be a relationship between external hair cell activity and tinnitus in individuals with normal hearing. On the other hand, the difference between DPOAE amplitudes recorded at other frequencies and tinnitus effect was not statistically significant. This indicates that tinnitus is not statistically significant. This indicates that tinnitus is not caused by external hair cells exclusively. Keywords: Tinnitus, external hair cells, otoacoustic emission, signal noise ratio