Can brain shrinkage be associated with hearing loss? A new study finds brain shrinkage is the latest in a list of health problems associated with hearing loss. Studies have shown the brain becomes smaller with age, but the shrinkage seems to be accelerated in older adults with hearing loss. These findings add to a growing list of health issues associated with hearing loss, including increased risk of falls, hospitalizations, dementia, and diminished overall physical and mental health.
The ongoing study (established in 1958) from the Baltimore Longitudinal Study of Aging compared brain changes over time between adults with normal hearing and adults with hearing loss. Previous studies linked hearing loss with marked differences in brain structure compared to those with normal hearing. Specifically, the structures that process information from sound tended to be smaller in size in people with impaired hearing.
As part of the study, participants underwent yearly MRIs to track brain changes for up to 10 years. At the start of the study, 75 had normal hearing and 51 had, at minimum, a 25 decibel hearing loss.
After analyzing the MRIs over the years, those participants whose hearing was impaired at the start of the study had accelerated rates of brain atrophy compared to those with normal hearing. Those with hearing loss had lost more than 1 cubic centimeter of brain tissue each year compared to those with normal hearing. The hearing impaired also had significantly more shrinkage in the regions which are responsible for processing sound and speech. Shrinkage in those areas might simply be a consequence of an “impoverished” auditory cortex, which could become atrophied from lack of stimulation. Some of these atrophied regions also play a role in memory and sensory integration and have been shown to be involved in the early stages of mild cognitive impairment and Alzheimer’s disease.
This latest study adds urgency to treating hearing loss rather than ignoring it.