Hearing Loss and the Aging Brain

Hearing loss can affect brain function in the elderly

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Some degree of hearing loss is expected in the later years of life. But does fuzzy sound mean more than just not hearing the doorbell ring?

A new study suggests that hearing loss in older adults may be associated with faster development of the type of cognitive declines, or thinking problems, that are also associated with advancing age.

Researchers studied over 3,000 older adults and followed them over six years. They found that those with hearing loss developed problems with mental abilities sooner than those with normal hearing.

"Consult your physician if you start having trouble hearing."

Frank R. Lin, MD, PhD, of The Johns Hopkins Center on Aging and Health in Baltimore, and colleagues led the study to find out if there was a relationship between hearing loss and how well the brain functions among the elderly.

In order to carry out the research, the authors used data from an already existing study called the Health, Aging, and Body Composition Study. In that study, 3,075 Medicare beneficiaries between the ages of 70 and 79 were recruited between 1997 and 1998.

Each of the participants was a well-functioning older adult that lived in a community in either the Pittsburg or Memphis area. All adults were either black or white, no other races or ethnicities were included.

To qualify for the study, the participants had to be reasonably physically fit. They had to report no difficulty with walking a quarter mile, climbing 10 steps without resting or performing basic activities of daily living.

In the fifth year of the study, 2,206 participants’ hearing was tested. After that, their hearing was tracked for six years.

The researchers also measured the participants’ cognitive, or thinking, abilities at various points in the study period. At years five, eight, ten and eleven a standardized test was administered that evaluated the adults’ orientation, concentration, language and memory.

Another test was administered at the same times that measured nonverbal abilities like putting numbers together with symbols quickly in a timed test.

The results of these two tests indicated whether participants had thinking or acting problems, also called cognitive impairment.

Of the 1,984 older adults whose hearing was tested, those with hearing loss were more likely to be male, older, of white race/ethnicity and have a history of smoking than those with normal hearing. Mild and moderate hearing loss was much more common than severe hearing loss.

Based on their analysis, the researchers found that hearing loss is associated with faster cognitive decline and new cognitive impairment among older adults living in communities.

Older adults with hearing loss had a 30 to 40 percent higher rate of increasing already-existing cognitive problems during a six-year period compared to participants with normal hearing. Those with hearing loss that didn’t start out the study with cognitive problems had a 24 percent increased risk for developing cognitive problems compared to those with normal hearing.

According to these results, older adults with hearing loss on average would take only 7.7 years to decrease their cognitive test scores in a significant way, while individuals with normal hearing would take 10.9 years for a similar decline.

“In conclusion, our results suggest that hearing loss is associated with accelerated cognitive decline and incident cognitive impairment in older adults,” the authors wrote.

They also noted that further research is needed to understand why hearing loss is associated with brain function decline and if there might be treatment options to influence this association.

The study was published January 21 in the JAMA Internal Medicine.

Dr. Lin reported that he works as a consultant to Pfizer, a pharmaceutical company, and as an unpaid speaker for Cochlear Europe, a cochlear implant manufacturer.

The study was funded by the National Institute on Aging and The Johns Hopkins Older Americans Independence Center. Financial support was also provided by the National Institute of Nursing Research, the National Institute on Deafness and Other Communication Disorders and by a Triological Society/American College of Surgeons Clinician Scientist Award.

Reviewed by: 
Review Date: 
January 23, 2013
Last Updated:
January 26, 2013