According to a study conducted by researchers at Johns Hopkins University School of Medicine and the National Institute on Aging, older adults with hearing loss lose brain tissue faster and to a greater degree than adults with normal hearing.
According to a study conducted by researchers at Johns Hopkins University School of Medicine and the National Institute on Aging, older adults with hearing loss lose brain tissue faster and to a greater degree than adults with normal hearing. The findings join a growing list of health issues associated with hearing loss, including increased risk of dementia, falls, hospitalizations, and diminished physical and mental health overall.
The study by Frank Lin, M.D., Ph.D. and his colleagues used data collected as part of the ongoing and well-respected Baltimore Longitudinal Study of Aging to compare brain changes over time in 126 participants. Each one underwent yearly magnetic resonance imaging (MRI) to track brain changes for up to 10 years. Participants also underwent complete physicals at the time of their first MRI in 1994, including hearing tests. At the beginning of the study, 75 had normal hearing, and 51 had impaired hearing. After analyzing the participants’ MRIs over subsequent years, researchers discovered that those whose hearing was already impaired at the start of the study had accelerated rates of brain atrophy compared to those with normal hearing, losing more than an additional cubic centimeter of brain tissue. There was also significantly more shrinkage in the brain structures responsible for processing sound and speech.
According to the researchers, shrinkage in those areas might simply be caused by an "impoverished" auditory cortex, which atrophies from lack of stimulation. Some of these structures also play roles in memory and sensory integration, however, and have been shown to be involved in the early stages of mild cognitive impairment and Alzheimer's disease.
The study underscores the urgency to treat hearing loss rather than ignore it. "If you want to address hearing loss well," Dr. 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."
The research was supported by the intramural research program of the National Institute on Aging, the National Institutes of Health's National Institute on Deafness and other Communication Disorders (K23DC011279), a Triological Society/American College of Surgeons Clinical Scientist Development Award and the Eleanor Schwartz Charitable Foundation.