Researchers here note correlations between hearing loss and specific microstructural changes in the brain indicative of loss of function. Evidence from studies involving patients with and without hearing aids suggests that hearing loss accelerates age-related neurodegeneration. Depriving the brain of sensory processing activity may produce maladaptive compensatory changes, or may simply be a case of "use it or lose it", as is the case for muscle tissue. The mechanisms involved are not yet fully understood, and the situation is complicated by underlying processes of aging that contribute separately to dysfunction in both the brain and the auditory system.
Hearing loss affects more than 60 percent of adults aged 70 and older in the United States and is known to be related to an increased risk of dementia. Researchers employed hearing tests and magnetic resonance imaging (MRI) to determine whether hearing impairment is associated with differences in specific brain regions. Individuals enrolled in this observational study who had hearing impairment exhibited microstructural differences in the auditory areas of the temporal lobe and in areas of the frontal cortex involved with speech and language processing, as well as areas involved with executive function.
"These results suggest that hearing impairment may lead to changes in brain areas related to processing of sounds, as well as in areas of the brain that are related to attention. The extra effort involved with trying to understand sounds may produce changes in the brain that lead to increased risk of dementia. If so, interventions that help reduce the cognitive effort required to understand speech - such as the use of subtitles on television and movies, live captioning or speech-to-text apps, hearing aids, and visiting with people in quiet environments instead of noisy spaces - could be important for protecting the brain and reduce the risk of dementia."