The variability in potential biomarkers for cochlear synaptopathy after recreational noise exposure

Objectives: Speech-in-noise tests and suprathreshold auditory evoked potentials are promising biomarkers to diagnose cochlear synaptopathy (CS) in humans. This study investigated whether these biomarkers changed after recreational noise exposure. Design: The baseline auditory status of 19 normal hearing young adults was analyzed using questionnaires, pure-tone audiometry, speech audiometry and auditory evoked potentials. Nineteen subjects attended a music festival and completed the same tests again at day 1, day 3 and day 5 after the music festival. Results: No significant relations were found between lifetime noise-exposure history and the hearing tests. Changes in biomarkers from the first session to the follow-up sessions were non-significant, except for speech audiometry, that showed a significant training effect (performance improvement). Conclusions: Despite the individual variability in pre-festival biomarkers, we did not observe changes related to the noise-exposure dose caused by the attended event. This can indicate the absence of noise-exposure-driven cochlear synaptopathy in the study cohort, or reflect that biomarkers were not sensitive enough to detect mild CS. Future research should include a more diverse study cohort, dosimetry and results from test-retest reliability studies to provide more insight into the relationship between recreational noise exposure and cochlear synaptopathy.