Although the brain becomes smaller with age, the shrinkage seems to be fast-tracked in older adults with hearing loss, according to the results of a study by researchers from Johns Hopkins and the National Institute on Aging. The findings add to a growing list of health consequences associated with hearing loss, including increased risk of dementia, falls, hospitalization, and diminished physical and mental health overall.
For the study, Frank Lin, M.D., Ph.D., and his colleagues used information from the ongoing Baltimore Longitudinal Study of Aging to compare brain changes over time between adults with normal hearing and adults with impaired hearing. After analyzing their MRIs over the following years, Lin and his colleagues, reporting in an upcoming issue of Neuroimage, say those participants whose hearing was already impaired at the start of the sub-study had accelerated rates of brain atrophy compared to those with normal hearing. Overall, the scientists report, those with impaired hearing lost more than an additional cubic centimeter of brain tissue each year compared with those with normal hearing.
Those with impaired hearing also had significantly more shrinkage in particular regions, including the superior, middle and inferior temporal gyri, brain structures responsible for processing sound and speech. “Our results suggest that hearing loss could be another ‘hit’ on the brain in many ways,” Lin explains. The study also gives some urgency to treating hearing loss rather than ignoring it. “If you want to address hearing loss well,” Lin says, “you want to do it sooner rather than later. If hearing loss is potentially contributing to these differences we’re seeing on MRI, you want to treat it before these brain structural changes take place.”