New research finds that age-related hearing difficulties are, in some cases, the result of structural changes in the brain, not just normal hearing loss.

The ability to recognize words is governed by a small portion of the brain’s auditory cortex, according to researchers at the Medical University of South Carolina. One group of young adults, aged 19 to 39, and one group of older adults, aged 61 to 79, participated in hearing tests while undergoing an MRI brain scan to gauge the brain’s role in audio understanding. Subjects were tested on their ability to identify words, some of which were filtered to reduce intelligibility.

After adjusting for other age-related hearing difficulties, older subjects with comparatively smaller portions of the auditory cortex were less able to identify challenging words than either younger participants or older participants with a normal-sized auditory cortex. Understanding that hearing loss can also be the result of comparatively diminished brain function could help lead to new therapies, according to researchers. Preliminary findings of the study are to be presented at the 2009 Midwinter Meeting of the Association for Research in Otolaryngology in Baltimore.