Evaluation Of The Olivocochlear Efferent System Activation After Exposure To Music In Young Individuals

Objective: In this study, a protective role of the olivocochlear efferent system activation on the hearing system in young individuals after music exposure (ME) was investigated.Methods: Twenty two young adults aged 19-22 years (mean age +/- standard deviation, 19.63 +/- 0.83) with normal hearing participated in the study. All participants listened to music at 85.4 dBA for 30 minutes. An audiological evaluation including pure tone audiometry, immittance measurements, Distortion Product Otoacoustic Emissions (DPOAEs), and Transient Evoked Otoacoustic Emissions (TEOAEs) with and without contralateral acoustic stimuli (CAS) was done before ME, immediately after ME, and after a rest period.Results: No significant differences in pure tone audiometry and the DPOAE signal-to-noise ratio (S/N-R) results were found among the three measurement sessions (before ME, immediately after ME, and after the rest period) in all measured frequencies (p>0.05). There was a significant increase in the contralateral stapes reflex threshold at 0.5 kHz, measured immediately after ME (p=0.02), while no significant difference was found in the measured frequency after resting (p>0.05). In the TEOAE S/N-R responses, a statistically significant decrease was found at 1 kHz (p=0.016) and 1.4 kHz (p=0.009) immediately after ME, whereas no significant difference was found between the TEOAE S/N-R responses measured before ME and after resting (p>0.05). Compared to the conditions before the exposure, there was a statistically significant decrease (p<0.001) in all center frequencies measured immediately after ME and after resting conditions in the TEOAE amplitudes obtained in the presence of CAS.Conclusion: The contralateral stapes reflex thresholds increase after ME, and a significant suppression effect of the TEOAE amplitudes in the presence of CAS suggests that the olivocochlear efferent system plays a role in protecting the auditory system from acoustic trauma.