Hearing Loss May Speed up Brain Shrinkage in Elderly

Hearing loss may be associated with faster brain shrinkage if not treated early

(RxWiki News) The human brain shrinks as part of the normal aging process, but one new study found that hearing problems may be linked to a faster shrinkage process.

This new study showed that the brains of people with hearing loss shrank more than those with normal hearing.

The researchers believe treating hearing problems early may reduce the risk of cognitive health issues later in life.

"Discuss treatment options for hearing loss with your doctor."

This study was led by Frank R. Lin, MD, PhD, of the Department of Geriatric Medicine at Johns Hopkins University in Baltimore, MD.

The researchers used data from the Baltimore Longitudinal Study of Aging, a study that began in 1958 to track various health factors in thousands of men and women.

This study by Dr. Lin and colleagues looked at 126 patients between the ages of 56 and 86 who, as part of the Baltimore Longitudinal Study of Aging underwent yearly magnetic resonance imaging (MRI) to track brain changes for up to 10 years. Each of these participants received a full physical, including a hearing test prior to the first MRI, which began in 1994.

When this research began, 75 of the participants had normal hearing and 51 had impaired hearing (a loss of at least 25 decibels).

The researchers found that the brains of participants who had hearing loss at the beginning of the study saw an increase in brain shrinkage of more than a cubic centimeter compared to participants with normal hearing.

The MRI images showed Dr. Lin and his team that the greatest shrinkage occurred in the superior, middle and inferior temporal gyri — an area of the brain associated with processing sound and speech. The researchers pointed out that these areas also play roles in memory and have been shown to be associated with mild cognitive impairment and Alzheimer’s disease.

“Our results suggest that hearing loss could be another ‘hit’ on the brain in many ways,” Dr. Lin said.

The research team was not surprised by the shrinkage in the temporal gyri area of the brain. They believe it was likely caused by the lack of auditory stimulation caused by the participants' impaired hearing.

This study also suggested that it may be important to treat hearing loss early rather than ignoring it. “If you want to address hearing loss well,” Dr. Lin said, “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 researchers pointed out that more research is needed specifically to verify if treating hearing loss early can reduce the risk of cognitive health-related problems later in life.

This study had several limitations, including the small number of participants and a lack of continuing hearing exams after the first MRI.

This study was published January 22 in NeuroImage.

The research was supported by the intramural research program of the National Institute on Aging and the National Institutes of Health’s National Institute on Deafness and other Communication Disorders.

Dr. Lin reported being a consultant to Cochlear Limited, being on the scientific advisory board of Pfizer and Autifony and being a speaker for Med El and Amplifon.

Review Date: 
January 23, 2014