Hearing Loss and Alzheimer’s Disease

 

Dear Readers,

Alzheimer’s Disease is a topic that hits close to home for many of us.  In our practice, we see a number of patients with dementias that co-exist with hearing loss. An important part of our job as Audiologists is to determine the extent to which hearing loss and hearing processing are contributing, or being affected by, the dementia.  Only then are we in a position to make recommendations about hearing treatments that may help these patients.  

Naturally, we’re very interesting in any information we can get on Alzheimer’s and hearing.  Please read on for some of that information.  As you’ll see, we definitely need MORE INFORMATION on this topic!

Alzheimer’s Disease and Hearing

Alzheimer’s is a mysterious and frustrating disease, diagnosed by a process of exclusion, hard to pinpoint when it starts, terrible to witness in its end stage (click http://www.nytimes.com/interactive/2010/06/02/health/te_alzheimers.html?ref=health for video on this topic). Few of us tend to think of hearing problems in the overall context of this overwhelming disease. But, that may be a mistake.

As far back as 1996, researchers found that the vast majority of patients with symptoms of Alzheimer’s also had hearing loss (Gold et al, 1996). That study concluded that:

“The extraordinarily high prevalence of hearing loss in this selected population suggests that a hearing evaluation should be part of any assessment of cognitive function.”

Alzheimer’s disease attacks the processing centers of the brain.  Auditory processing centers are very complex.  What do we mean by that?  Well, auditory processing of speech involves perceiving sounds, integrating them into meaningful units (words), connecting those units into conceptual units (phrases and sentences), and interpreting the conceptual units in terms of context (for example,  ”He’s over there” only makes sense if you have some idea of what “there” means).  Wow.  It’s complicated!

Given the complexity of auditory processing, it seems likely that it could be a victim of Alzheimer’s disease, along with other more obvious memory problems that we usually associate with Alzheimer’s.   In fact, central auditory processing is significantly lower in patients with dementia AND/OR mild hearing loss than it is in the average 80 year old without those problems (JAMA, 2008).

But what about treatment?  Can hearing aids help people with Alzheimer’s or do they just serve to introduce more confusion?  Max Chartrand, a PhD audiologist,  published a strong call to action in this regard way back in 2001.  His article includes a number of interesting statistics and makes the following statement: 

For the [Alzheimer's disease, AD] population there is persuasive evidence that hearing instrument use, combined with proper aural rehabilitation (in a multidisciplinary setting), can be a cost-effective approach to alleviating many AD-identified symptoms in patients who have AD and hearing loss. In this case, such a program has been found to lessen many debilitating symptoms, including depression, passivity, negativism, disorientation, anxiety, social isolation, feelings of helplessness, loss of independence and general cognitive decline.

We’re interested in hearing from our readers on this topic.  In the meantime, we will continue to research it and get back to you as we find more information linking hearing, auditory processing, and the ravages of Alzheimer’s disease.

References

1.  Gold, M. Lightfoot, L.A., Hnath-Chisolm, T. (1996). Hearing loss in a memory disorders clinic. A specially vulnerable population. Archives of Neurology, 53(9): 922-8.

2.  JAMA and Archives Journals (2008, July 23). Memory impairment associated with sound processing disorder. ScienceDaily, as reported in Dancer, J., Advance for Audiologists, May/June 2009: p 58.

3.  Chartrand, M.S. (2001).  Hearing Health and Alzheimer’s Disease.  http://www.hearingreview.com/issues/articles/2001-11_02.asp called out June 22, 2010. 

4.  http://www.portfolio.mvm.ed.ac.uk/studentwebs/session3/7/ADHP.htm called out June 22, 2010.

5.  http://www.nytimes.com/interactive/2010/06/02/health/te_alzheimers.html?ref=health

 

 

Submitted for your consideration and commentary,

Holly Hosford-Dunn PhD and Sharon K. Hopkins MS

Your Audiologists!