What is Known of the Mechanisms of Age-Related Hearing Loss

Hearing loss is prevalent in older individuals, either involving the destruction of sensory hair cells in the inner ear, or the axonal connections between those hair cells and the brain, or both. Hair cells do not normally regenerate to any great degree in adults, which has led to efforts to grow patient matched replacement cells, or reprogram native cells to convince them to produce new hair cells. Despite promising advances, it is not as yet a solved problem.

Age-related hearing loss, or presbycusis, is a common cause of hearing loss in elderly people worldwide. It typically presents as progressive, irreversible, and usually affects the high frequencies of hearing, with a tremendous impact on the quality of life. Presbycusis is a complex multidimensional disorder, in addition to aging, multiple factors including exposure to noise, or ototoxic agents, genetic susceptibility, metabolic diseases, and lifestyle can influence the onset and severity of presbycusis.

With the aging of the body, its ability to clean up deleterious substances produced in the metabolic process is weakened, and the self-protection and repair function of the body is reduced, which in turn leads to irreversible damage to the cochlear tissue, resulting in the occurrence of presbycusis. Presently, oxidative stress (OS), mitochondrial DNA damage, low-grade inflammation, decreased immune function, and stem cell depletion have been demonstrated to play a critical role in developing presbycusis. The purpose of this review is to illuminate the various mechanisms underlying this age-related hearing loss, with the goal of advancing our understanding, prevention, and treatment of presbycusis.

Link: https://doi.org/10.3389/fnins.2023.1253574