Contralateral suppression of transient evoked otoacoustic emissions in adolescents with and without tinnitus

Abstract

The severity of tinnitus has a high variability; it can potentially cause serious anxiety disorders and in some cases it can even lead to depression. Currently, one of the hypotheses of the genesis of tinnitus involves a deterioration in the functioning of medial olivocochlear system (MOCS). The functioning of the MOCS is evaluated through the contralateral suppression (CS) of transient evoked otoacoustic emissions (TEOAEs) by comparing the amplitudes without and with contralateral acoustic stimulation (CAS). The aim of the present study was to analyze the functioning of the MOCS in adolescents with and without tinnitus through the CS of the TEOAEs. A cross-sectional correlational descriptive study was carried out, involving 77 adolescents (n = 154 ears) with normal hearing with and without tinnitus, who underwent TEOAEs testing without and with CAS using white noise at 50 dB. The results evidenced that the adolescents without tinnitus showed higher global amplitude and higher amplitude in the frequencies 1000, 1500, 2000, and 3000 Hz, in both conditions without and with CAS, in comparison to the adolescents with tinnitus. This difference was statistically significant (p<0.05) in the 1000 Hz frequency and in the global amplitude, without and with CAS. In addition, the adolescents with tinnitus showed less difference between the global amplitudes in the conditions without and with CAS (suppression effect). These results suggest a possible relation between the functioning of the MOCS and the presence or absence of tinnitus, which could contribute to confirm the hypothesis of the involvement of the MOCS in the generation of tinnitus.