No evidence for hidden hearing loss due to noise exposure in young adults with a normal audiogram

Abstract

Cochlear synaptopathy, or “hidden hearing loss,” refers to a loss of synapses between inner hair cells and auditory nerve fibers, and affects primarily low-spontaneous-rate fibers that encode moderate-to-high intensity sounds. In rodent models, cochlear synaptopathy has been shown to occur as a result of noise exposure even when threshold sensitivity is unaffected. We tested 126 young humans with normal audiograms and a wide range of lifetime noise exposures quantified using a questionnaire. Our electrophysiological and behavioral measures were designed to be sensitive to the contribution of low-spontaneous-rate fibers. We predicted that our test battery would reveal that noise exposure is associated with attenuated electrophysiological responses, and elevated behavioural thresholds, especially at higher levels and frequencies. However, there was no relation between noise exposure history and auditory brainstem response wave I amplitude, nor performance on psychophysical tasks including modulation detecti...