Decreased Hearing in Older Adults May Cause Decrease in the Amount of Gray Matter in Auditory Centers of the Brain
Hearing loss is one of the most prevalent health complaints in adults over the age of 60 and a major factor in speech comprehension difficulties. The goal for researchers at the Departments of Neurology and Neuroscience at the University of Pennsylvania in Philadelphia and the Volen National Center for Complex Systems at Brandeis University in Waltham, Massachusetts was to examine the effects of hearing ability on the brain processes supporting spoken language processing in adult humans.
The study, published in The Journal of Neuroscience, utilized functional magnetic resonance imaging (MRI) to monitor activity in the brain while older adult subjects with normal-level hearing for their age listened to sentences that varied in the amount of linguistic comprehension needed to understand them. Researchers found that differences between subjects in hearing ability predicted the amount of language-focused brain activity recruited to understand the spoken sentences in bilateral superior temporal gyri (including primary auditory cortex,) thalamus, and brainstem.
In a second experiment, researchers looked at the relationships between hearing ability and cortical structural integrity with voxel-based morpometry. They found a significant relationship between hearing ability and the amount brain matter volume in the hearing centers of the brain.
As age-related hearing loss sets in, the corresponding auditory sections of the brain shrink, as well. This reduction of the auditory centers in the brain leads to a reduction in total brain volume. The results were found after examining brain activity in the hearing-impaired elderly and measuring the size of the auditory cortex in the brain.
The study’s authors recommend hearing aids as a proactive method to preserve precious auditory centers in the brain and assist an aging person with hearing-impairment. The study also indicated that the findings have major implications for younger people with damaged hearing as a result of exposure to excessive noise.
For more on the effects of hearing-impairment on the auditory centers of the brain, read the original Journal of Neuroscience study here: http://bit.ly/p8on5o.