Deafness linked to Dementia?

A recent article suggests that those with moderate to severe hearing loss may be at greater risk of dementia. The association was found in the Baltimore Longitudinal Study of Aging, in a prospective study, a group of 795 participants had both hearing and cognitive testing over a five year period from 1990 to 1994, and were free of confirmed or suspected dementia at baseline. The authors suggest a relationship between loss of ability to hear verbal communication and dementia.

The idea that the social isolation due to hearing loss might be harmful is not a new one. However to find such a direct link of hearing loss to something as serious as dementia is interesting. What kinds of things would be important to know about the study? Well, things like: When was the baseline evaluation identifying individuals as free of confirmed or suspected dementia? Was it in 1958 or was it in the 90’s when this evaluation occurred? AND Why was the hearing test done? Was it part of the longitudinal study protocol or was it individuals who also had a test that was then obtained by the study?
So what could this mean? Does it mean that social isolation is harmful? (do other socially isolated people get dementia at higher rates?) Does it mean that some similar mechanism is involved with both hearing loss and dementia? Is it a physiologic process? If so, what might be involved?

Do others with moderate to severe hearing loss have the same association with dementia? (what about those with hearing loss from birth or early in life? What about hearing loss due to accidental injury?) Do those with dementia have a higher rate of moderate to severe hearing loss?

An interesting finding – but one that certainly raises many more questions. I would think several of these questions could be answered in existing cohorts of those with dementia or those with hearing loss.

Here is a link to a report of this study which was originally published in the Archives of Neurology (Lin, 2011, Hearing Loss and incident dementia., Archives of Neurology, 68(2), 214-220).
http://www.medpagetoday.com/Neurology/Dementia/24867?utm_content=GroupCL&utm_medium=email&impressionId=1297757253079&utm_campaign=DailyHeadlines&utm_source=mSpoke&userid=230719