Studies show relationship between untreated hearing loss and dementia

Studies at Johns Hopkins University have linked untreated hearing loss to decreases in cognitive functioning.

“For individuals older than 60 years, more than one-third of the risk of dementia was associated with hearing loss,” the studies reported. More recently, researchers at Johns Hopkins and the National Institute on Aging have reported that the brain atrophy that normally occurs with age appears to be fast-tracked in older adults with hearing loss.

“Hearing loss means a loss of cellular function in the inner ear, leading to less stimulation of the auditory nerve,” said Dr. Shawn Key of Better Hearing and Balance Connection. “With a decrease of neural stimulation over time, the nerve fibers become weaker and neural atrophy may occur.”

Dr. Frank Lin, an otologist with Johns Hopkins, and his colleagues reviewed the magnetic resonance imaging (MRI) studies over the course of 10 years for patients with normal hearing and patients with hearing loss. They found that “participants whose hearing was impacted at the start of the study had accelerated rates of brain atrophy compared to those with normal hearing.”

Research studies have also suggested that people with untreated hearing loss are likely to become frustrated and socially isolated, and this isolation has been linked to depression. With less social stimulation, there is less activation of the parts of the brain that process speech and language.

Lin’s research found significant atrophy in the superior, middle and inferior temporal gyri — brain structures responsible for processing sound and speech. However, the auditory cortex does not only process sound and language. The middle and inferior temporal gyri also plays a role in memory and sensory integra- tion and have been shown to be involved in the early stages of mild cognitive impairment and Alzheimer’s disease.

“Obviously, the sooner we can amplify to correct a hearing loss, the less likely neural atrophy will occur and the greater success at maintaining neural integrity of the auditory nerves and auditory cortex,” Key said.

Key went on to say that if the hearing aids are not worn consistently (as many waking hours per day as possible), atrophy is still likely. He encourages those with hearing loss to utilize hearing aids in order to improve understanding, avoid social isolation, and improve quality of life.

Dr. Gretchen Magee and Key are audiologists with Better Hearing and Balance Connection, located at 407 Town Center East in Bella Vista and at 906 NW 8th Street in Bentonville. A free hearing screening and hearing aid consultation can be scheduled by calling (479) 657-6464.