Alzheimer's Disease: Issues and Answers

Editor's Note: Alzheimer's disease (AD) can/does clinically ''overlap'' with hearing loss. AD is very important to us as hearing healthcare professionals. Dr Chartrand detailed his thoughts on AD in an excellent article, previously published on Audiology Online (The Absence of Hearing Healthcare in a so-called ''Tidal Wave of Alzheimer's Cases'').

In response to his article, we received many inquiries and letters of appreciation. We are proud to publish the following letter written to, and answered by, Dr Chartrand. I believe this is an important correspondence and I am appreciative of the permissions received (from the authors) to share this (edited) information with the Audiology Online community.

----Douglas L. Beck Au.D, Editor-In-Chief.


Dear Dr. Chartrand:

Thank you very much for your exhausting and exciting information. I'm working in the field of geriatrics for 5 years. Until last year, we had a quite precise evaluation of the problem of hearing impairment in all our patients: all of them had (as part of the comprehensive assessment) audiometry and the MMS (partly administered through the earphones of the audiometer!) and many of them also had thorough neuropsychologic assessments.

I always felt I was not able to understand all the possible aspects of the interaction of hearing impairment and cognitive decline. There are many aspects to this dilemma; First, a methodologic problem because both the assessment of cognitive decline by conventional means and of hearing impairment, are importantly reciprocally influenced. Second, the pathophysiological pathways of the two syndromes likely share important aspects, so that each might have common causes leading to both kinds of impairment. Third, the consequence of both pathologies on a phenomenological level may coexist in a vicious circle of a reciprocal worsening, which we could describe as ''functional'' (e.g. a person with significant hearing loss might be classified as ''functionally cognitively impaired'' due to a communication problem).

Your article gave me important clarification (and confirmation) of these aspects, although it raises more questions than it gives answers! Nonetheless, this is the beginning of a new awareness of the problem, and a new way of thinking about it, and it might offer some very important new opportunities and fields of research!

I must admit, I didn't perform a serious literature search on this topic, but I think the aspects you cited should be made more public in order to increase the awareness of the geriatric world, don't you think so?

I'm sending copies of this important article to my colleagues. Certainly they are very interested in this item and might know better than me the literature.

Thank you again for your excellent article. Kind regards, Guido Ongaro

*********************************************************************************************************
Dear Dr. Ogaro,

This is in reply to your excellent question relative to alternative approaches in helping Alzheimer's patients who also suffer from significant unmitigated hearing loss. Your concern was that more is needed than simply applying the Mini Mental State Exam (MMSE), a verbally applied screening device, and recommending hearing instruments. While space and time will not allow me a more definitive or exhaustive treatment of the question at hand, I did want to highlight some important points that may help spark more discussion on this vital topic. I am copying this email to a few acquaintances and colleagues who may have something to add too!

1. The main concern arises out of the fact that AD increases in the over 65 population by a factor of two for every 5 years forward, and even faster above age 80, and is approaching epidemic proportions among the very elderly.

2. Current psychologic approaches call for verbal screening, and afterward an even more exhaustive ''verbal'' assessment to help differentiate pathologies, along with drug therapy. The fact that these tests are routinely applied orally is a serious problem, because of the exponential rise in advancing hearing impairment in the older adult population. During the 1960s and 1970s we went through the same thing with the universal application of verbal IQ tests for schoolchildren---whole theses were published asserting, among other things, that hearing impaired (and deaf) children typically landed in the lower percentiles of intelligence...Shame on us for such a short-sighted conclusion. The same thing is happening now with the older population, ignoring the disability that defies truly objective measurement by oral/aural means.

3. You asked about a written MMSE, but I'm not sure the psychometrics have been worked out scientifically enough to render it a fair screening method. Somewhere in the constellation of ways to measure cognition there needs to be a Manhattan Project-size effort to find that magic pill of the older (presumably hearing impaired adult). In the meantime, I personally prefer the Middlesex Elderly Assessment of Neural Status (MEAMS) screening test as more reliable than the MMSE. MEAMS is more neurophysiologically oriented, and at least has two versions to allow a more objective retest (keeping it more open-set).

4. But the deeper issue is where does the audiometric battery fall into the mental health regimen? In my experience and in a review of current practice I do not find hearing health in any of the preliminary instructions for any AD test to-date. Because of the prevalence of unmitigated hearing loss in the AD population (running as high as 92%!) I feel that audiometric assessment should be one of the FIRST orders of business, and certainly BEFORE a cognitive testing begins. The results of the audiometric test can help determine the next course of action. If the results show a serious hearing loss, auditory rehabilitation should be the next step, of course. And this is where the harbinger to the established order of things comes into play:

Auditory rehab for a patient suspected of early stage AD requires at least 3-4 months to complete. Auditory deprivation, cortical reassignment and remediation (see Jastreboff and Hazell's approach for more information on this point), and long-term progress should render the patient to a state where cognitive testing actually has meaning. In other words, until the hearing/language components have been addressed, cognitive testing and treatment are suspect.

5. This brings me to another subject of great concern. At last report the two major pharmaceutical trials now under way in the United States for AD drugs about to come out on the market report no mandatory provision for auditory assessment and remediation of study subjects. Possibly doing so would slow down their trials and might even render the majority of subjects no longer candidates for the rest of the trial---kind of muddy state of affairs to the clinician who likes things simpler and more straightforward. But I still say that if the new drugs are to be used in the manner I understand they are going to be used, and on a population who by and large suffer as much from unmitigated hearing loss as they do cognitive decline, that a serious breach of ethics will ensue. The only remedy to this likelihood is for the investigators and those that design their study to back up and put hearing health in the forefront where it belongs. Then, their results will mean something.

6. You also raised the question as to which comes first (in the vein of ''the chicken or the egg''): the hearing loss or the cognitive decline? Since there are so many causal factors contributing to both, it is hard to know in any specific case. But, something we've observed in years of auditory research is that the pathophysicological pathways for both presbycusis and dementia often share commonalities. To any informed observers there appear to be a close correlation between functional and organic pathologies. The problem is that we tend to recognize organic causes only by events (multi-infarct/ISA/stroke) while ignoring similar outcomes wrought by ''degenerative processes'' (microvascular degeneration, hyperlipidemia, and their medical mismanagement, including medicine toxicity). The shades of gray conditions, to me, are far more causal over the broader population than the easier-to-detect events are. As you well know, it is too convenient to classify a dementia based upon an event, when much of the population presents with pre-event pathologies. The second part of this are the effects of hearing loss in the deprivation domain. If the Jastreboff/Hazell model for hyperacusis is actually correct (and I believe it is), then the current drug-oriented methodology for AD treatment needs to be changed to a cortical retraining one. As an interesting review of recent findings in neuroplasticity and brain-remapping rehabilitation approaches I suggest The Mind and the Brain: Neuroplasticity and the Power of Mental Force by Jeffrey M. Schwartz, M.D. (Regan Books/Harper Collins). I feel the points made above in light of recent advancements in understanding how the brain repairs itself is the key to improving mainstream AD treatment protocol.

7. But lest the lowly hearing aid be shuffled aside in the discussion, I need to say that since most of the heavy auditory/cognitive lifting is borne by the patient, in spite of what professionals do or don't do, the least we can do is make sure every hearing impaired patient who is suspected of dementia enjoys the best amplification strategy available to them. Translated, we need to consider the lack of audiologic referral of these patients an ethical breach as serious as, say, failing to give a thorough physical examination on a patient about to undergo invasive surgery.

8. Finally, I must commend you for your interest in the question at hand---in experience, there is a vast shortage of such interest, and I think only because of general lack of awareness about the prevalence and seriousness of hearing loss in the elderly population. I recall a few years back when a certain audiologist who had attended one of my courses on Audition, Cognition and the Human Brain enthusiastically took all the material from that course and triumphantly was about to visit a local Alzheimer's clinic that had just opened near her office. Before she went she called me for some pointers---to which I warned her not to be too disheartened when they show her the door, as the philosophy of what I taught is in direct conflict with the financial model upon which the AD treatment apparatus is built. It is not good business to make people well, and certainly not for the relatively low cost of auditory rehab----why, what would happen to the plethora of psychotropic drugs and legions of therapists who make their judgments based on verbal skills of older patients??? Anyway, it turns out that she was shown the door, treated as a heretic, and in all likelihood she, like many before her, went back to banging her head against the proverbial wall.

Again, thanks for writing, and it is hoped the above stimulates some ideas and discussion that can lead us toward actually performing a better service to this growing population. And thank you for your kind comments on the Audiologyonline article.

Best Regards,

Max S. Chartrand, Ph.D.
Health & Human Services/Research in Communicative Disorders DigiCare
Hearing Research & Rehabilitation P.O. Box 706
Rye, Colorado 81069
(719)676-3277 (V/TDD)
(719)676-6882 (Fax)
chartrandmax@aol.com
www.digicare.org


Author Bios:

Dr. Ongaro was born in Giubiasco, Southern Switzerland, in 1965. After college in Bellinzona, he attended the medicine formation at Zurich University where he graduated in 1990. From 1991 to 2001 he accomplished his training in internal medicine and geriatrics, including one year in pathology and one year in psychiatry in Zurich. In 2001 he attended a research fellowship at Istituto Auxologico Italiano in Milan and he is now working as chief resident in Bellinzona and Orselina, Ticino, Switzerland. 1999-2000 he participated to a postgraduate course of the European Academy for Medicine of Ageing (EAMA) and became a member of the Academy.

Dr. Chartrand serves as director of research for DigiCare® Hearing Research & Rehabilitation, and is a faculty member of the American Conference of Audioprosthology and an approved instructor for the International Institute for Hearing Instruments Studies. Fax correspondence: 719-676-6882 or email to chartrandmax@aol.com.