Not crazy at all -- in fact a great observation! This is true in hearing. The association between hearing loss and cognitive decline has been known for some time, but Dr. Frank Lin out of Hopkins has really pioneered this area recently. I remember his 2013
article getting some air time on the nightly news.
The thing to remember here is that association is not causation, so we can't make the leap that hearing loss
causes dementia. Dr. Lin describes the four working theories on the link between hearing loss and dementia in this
article and succinctly goes through them
here. They are 1) cognitive load, where the brain is working overtime to figure out the poor auditory signal, so it strains other brain systems, 2) changes in brain structure / function, where if you don't use it, you lose it, 3) social isolation, where people who have hearing loss stop engaging socially which adversely affects cognition and 4), a common cause for both dementia and hearing loss like small vessel disease from hypertension, diabetes, etc. Of course, it might be a combination of them all.
Can hearing aids and/or cochlear implants stop or reverse this? This is an area of current study, but the preliminary answers are assuring (e.g.
hearing aid article,
cochlear implant article). What I see in these articles is consistent with what I see with my patients as a whole.
That is just one more reason to protect long term hearing. Thanks for bringing that up!
