The Johns Hopkins Center on Aging and Health in Baltimore, funded by the National Institute of Health (NIH), studied 1,984 older adults (average age of about 77 years) over a six year period of time. All participants had normal brain function and hearing when the study began. They were given two tests at the beginning of the study that measured cognitive function by assessing memory, ability to follow commands, answer questions, and ability and speed with which they could match numbers to symbols. These tests were repeated three more times throughout the 6 year period in order to document decline. According to Lin, the association between hearing loss and cognitive decline was “clinically significant, with individuals having hearing loss demonstrating a 30% to 40% accelerated rate of cognitive decline and a 24% increased risk for incident cognitive impairment….compared with individuals having normal hearing.” Researchers found that those participants who had hearing loss were dealing with “significant cognitive impairment” 3.2 years sooner than those with normal hearing.

 

But just how are hearing loss and cognitive impairment connected? More research is needed in order to establish a direct link. Dr. Lin suggested that social isolation, one of the risk factors for dementia, is one possible explanation for cognitive decline. As hearing loss gradually progresses the compensatory strategies used to improve communication, such as lipreading, become less effective. When these strategies become less effective it can lead to increased social withdrawal. People with hearing loss often avoid social gatherings and withdraw as a result of frustration and/or embarrassment that stems from the inability to follow conversations. Social withdrawal and limited interaction with peers and family members can lead to depression and can possibly speed up the progression of dementia. Another explanation may be that the brain may also reallocate resources to help with hearing, at the expense of cognition. Dr. Lin stated that “if you’re constantly having to expend more (mental) energy decoding what you hear, then it comes at a cost. Our findings show how important it is for physicians to discuss hearing with their patients and be proactive in addressing hearing declines.”