Hearing Loss, Cataracts, and Dementia

There seem to be a lot of articles in the media currently discussing the statistical relationship between hearing loss and dementia.  Of course, we need to remember the axiom that "correlation does not necessarily mean causation."  Still, recent studies and informed observations are intriguing.  For example one study underway is looking at whether treating hearing loss can reduce the risk of cognitive decline.  

Johns Hopkins is leading a large National Institute on Aging study to see if hearing aids can safeguard seniors’ mental processes. The study has multiple locations and has recruited nearly 1,000 people ages 70–84 with hearing loss. One group is provided hearing aids, while another group receives aging education. By early 2023, the study should provide definitive results on whether treating hearing loss will reduce the risk of cognitive decline. In essence, we’ll know whether the use of hearing aids can potentially reduce brain aging and the risk of dementia.

Some of this research is going beyond examining the potential for common causes for the two processes (such as poor diet and inadequate exercise, as well as uncontrolled blood pressure or weight).  Researchers are asking whether a failure to hear clearly can actually damage the brain's function.  NPR's Sunday Edition (8.21.2022) includes  a five minute interview with Dr. Frank Lin, at John Hopkins Bloomberg School of Public Health, who addresses three "major brain mechanisms" that may be affected by untreated hearing impairments: (1) the potential impact of the load on a brain from having to work harder; (2) the potential for hearing loss to actually affect the integrity of the brain's structure  because of atrophy of an essential function, and (3) the potential for loss of hearing to contribute to social isolation, further reducing engagement that keeps people (and their brains) interacting with the world around them. 

Dr. Lin is also pleased about the FDA finally opening access for Americans to purchase over-the-counter hearing aids, a change he's worked on and supported for some eight years.  He points out that currently only some 15 to 20% of Americans who could benefit from hearing assistance are getting the help they need, probably because of high costs and reluctance to see doctors. Dr. Lin says that any theoretical risks from over-the-counter sales (such as over- or under-amplification) is significantly outweighed by the benefits. 

Oh, and while I'm at this, the research suggesting that older people who have cataracts removed may be "nearly 30% less likely to develop dementia" is also interesting.