Inner Hair Loss Mechanisms and Reduced Hearing

Inner hair loss can be attributed to hearing loss caused by metabolism noise exposure and cochlear synaptic loss. These cases of hair loss are the result of chronic noise exposure in mechanisms that degrade the neural cells of the auditory systems (Branham et al.,2019; Salvi et al.,2017). Furthermore, significant loss of high threshold fibers can cause hearing problems in noisy environments, implying a role for cochlear inner hair cells in ABR and auditory perception. Recent research in both mice and guinea pigs has shown that excessive exposure can result in irreversible degeneration of AN fibers, resulting in reversible exposure thresholds (Lin et al., 2011). Although the loss of AN’s peripheral terminals and hair cell synapses occurs quickly (within a few hours of exposure), loss of AN occurs slowly (within a few days), it was surprising to learn that cochlear neural degeneration could be a primary cause of hair loss rather than a secondary effect (Branham et al.,2019). According to the hypothesis that roughened AN fiber have a selective loss for the low-SR and heavy-three safety groups (Melcher et al., 1996; Mehraei et al., 2016), Kujawa and Liberman (2009) highlight the idea that approximately 40% of AN cochlear fiber can be permanently destroyed without a permanent threshold increase in a brain response that reflects the summed activity of the AN fiber in a brain response that reflects the summed activity of the AN fiber in their initial waves could be expanded.