Auditory Nerve Function Worsens With Age
The impact of noise is less clear, based on available studies.
By James W. Dias, Ph.D., and Carolyn McClaskey, Ph.D.
We recently conducted a study to address a debate among scientists about how age and a history of exposure to excessively loud sound, like rock concerts or power tools, may affect the auditory nerve.
Pure-tone audiometric thresholds for the right ear: younger (left) and older (right) participants. Red lines: females. Blue lines: males. Bold lines: group averages. Error bars: 95% confidence intervals. Credit: Dias et al./Hearing Research
The auditory nerve is the only structure that connects our ears to our brains. Damage to the auditory nerve can make it hard to understand people when they speak.
Scientists have found previously that aging and exposure to loud noise can damage the auditory nerve, but it is unclear how these two factors may work together to impact auditory nerve function. To examine this, we looked in a group of younger and older adults to see if a history of noise exposure compounded age-related damage to the auditory nerve.
Our findings were interesting. In our systematic review, study, and meta-analysis published in Hearing Research in June 2024, we found that older adults had poorer auditory nerve function, but functional deficits were not made worse by a history of noise exposure.
We then combined our findings with those from other scientists to further examine how age and noise exposure can affect auditory nerve function.
We found consistent evidence that auditory nerve function worsens with age, but the impact of noise exposure was less clear and seemed to depend on the specifics of each study.
Based on our results, we recommend that scientists studying noise exposure history and auditory nerve function carefully consider the design of their studies and exercise caution when interpreting their results.
James W. Dias, Ph.D., is a 2022–23 Emerging Research Grants scientist funded by the Meringoff Family Foundation, and Carolyn McClaskey, Ph.D., is a 2023–24 ERG scientist funded by Royal Arch Research Assistance. They are assistant professors in the department of otolaryngology–head and neck surgery at the Medical University of South Carolina, where coauthor Judy Dubno, Ph.D., a 1986–88 ERG scientist, is a distinguished university professor and director of research.