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Aging, Alzheimer's Disease, and Hearing Impairment: Highlighting Relevant Issues and Calling for Additional Research
American Journal of Audiology
Oftentimes an article in a popular magazine (whether print or online) can bring an important topic to the forefront and provide entrée into the social and economic impact it may have on a regional or global basis. Such was the case in a timely article on Alzheimer's disease (AD; see Dementia Care Costs Worldwide, 2007). While focused on economic issues, this piece was provocative, informative, and noteworthy, particularly for the lay public. The article provided up-to-date cost estimates of caring for individuals with AD and other forms of dementia: $76 billion in the United States and $315 billion worldwide. No doubt, these figures are conservative and probably represent just the tip of the iceberg. Other disturbing considerations indicate that the incidence of dementia is expected to more than double during the next 20 years, and therefore current research initiatives and clinical trials take on the utmost significance, since without an effective treatment or cure, this disease alone has potential to bankrupt the nation.
In the majority of cases, except in instances when a positive family history is clearly established, the cause of AD is unknown. However, the greatest risk factor is advancing age. An estimated 5.1 million Americans have the disease, and the majority are 65 years and older. According to the Census Bureau, the estimated 78 million baby boomers, born between 1946 and 1964, are now turning 60 at a rate of 330 every hour, and soon this group will reach the age where risk for developing AD is greatest.
The baby boomer population includes individuals who will be evaluated for communication difficulties associated with age-related hearing loss, and some may also exhibit signs of dementia; therefore, providing amplification is just one of many strategic issues that will challenge the practice of audiology in the near future. Being at the entry point in the hearing health care delivery system, the audiologist is in a unique position to identify "at risk" individuals, facilitate referral to the appropriate medical specialist (e.g., neurologist), and also provide comprehensive care. Medical referral is particularly important because dementia can be caused by many different conditions, some of which can be reversed. A cogent general review for audiologists on this topic is available (Dancer & Watkins, 2006).
The most prominent early sign of dementia of the AD type is memory loss, and more specifically, difficulty encoding and retaining new information (so-called episodic memory). Changes in memory are normal as we age, and some terms that have been used to describe this loss of function include "benign senescent forgetfulness" or more recently "minimal cognitive impairment." Most people with mild forgetfulness do not have AD. Nevertheless, while the terms benign and minimal may reflect normal components of the aging process, in other individuals these terms take on a different meaning. Indeed, they can be much more ominous and reflect a prodromal state whereby a significant proportion of individuals will convert to AD. Unfortunately, there is no simple way to predict who will and who will not convert.
In an attempt to be proactive, the Alzheimer's Association (www.alz.org) and other agencies have identified warning signs that can be helpful guides to permit early identification. These warning signs include the following:
- memory loss
- difficulty performing familiar tasks that were previously done with ease and regularity, such as cooking, making simple repairs, playing cards, paying bills, or balancing the checkbook
- problems with language, such as word-finding difficulties
- disorientation to time and place, inability to navigate to known locations, getting lost in familiar surroundings, inability to follow simple directions, wandering
- poor or decreased judgment
- problems with abstract thinking
- misplacing things
- changes in mood or behavior
- changes in personality
- loss of initiative
With respect to providing hearing care in the form of amplification to noninstitutionalized individuals with AD, there is not a large literature or information base from which to draw upon to provide guidance, although it is reasonable to assume that benefit will vary depending on stage of the disease. As the disease progresses, managing individuals becomes more difficult, particularly for their caregivers, who in many instances are members of the immediate family. Caring for individuals with AD can be quite demanding and can cause emotional, psychological, and physical problems. Therefore, inclusion of caregivers in educational counseling about amplification is just as important as providing relevant information to the patient. Thus, reducing caregiver burden by enhancing communication abilities is a valuable asset and important goal of the rehabilitation process. The limited but important research on this topic supports these observations. Available data suggest that use of amplification can be an effective tool not only in reducing the perceived handicap of the individual but also in reducing caregiver-identified problem behaviors (e.g., Palmer, Adams, Bourgeois, Durrant, & Rossi, 1999; Palmer, Adams, Durrant, Bourgeois, & Rossi, 1998). Others have extended this information as a means to model treatment efficacy (Durrant, Palmer, & Lunner, 2005). The methods of direct observation and multiple-baseline designs used in these hearing-related investigations have been shown to be valid and reliable metrics in other forms of dementia research (Wilmo & Nordberg, 2007). While the work of Palmer, Durrant, and colleagues is an initial starting point, more research in this area is obviously needed.
Conducting research and clinical trials in AD is difficult and demanding for all involved. Combined with other treatment modalities, improving communication abilities through the use of amplification is an effective way to enhance quality of life for both the AD patient and caregiver alike. In addition, audiologists should consider developing alliances with educational programs, support groups, primary care physicians, and neurology clinics as a way to be part of a comprehensive network of individuals needed to enhance clinical evaluations and treat this ravaging disease. I encourage audiologists to become actively engaged in this area; you bring unique skills to the table, and your services can be a great help to affected individuals and their families.
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- Dancer, J., & Watkins, P. (2006, January 9). Remember me? A guide to Alzheimer's disease and hearing loss. Retrieved April 20, 2007, from www.audiologyonline.com
- Dementia care costs worldwide reach $315 billion, 2007, April 16, Retrieved April 20, 2007, from www.forbes.com
- Durrant, J. D., Palmer, C.V., & Lunner, T. (2005). Analysis of counted behaviors in a single-subject design: Modeling of hearing aid intervention in hearing-impaired patients with Alzheimer's disease. International Journal of Audiology, 44, 31–38.[Web of Science][Medline]
- Palmer, C. V., Adams, A., Bourgeois, M., Durrant, J., & Rossi, M. (1999). Reduction of caregiver identified problem behaviors in patients with Alzheimer's disease post hearing-aid fitting. Journal of Speech, Language, and Hearing Research, 42, 312–328.
[Abstract/Free Full Text] - Palmer, C. V., Adams, S. W., Durrant, J. D., Bourgeois, M., & Rossi, M. (1998). Managing hearing loss in a patient with Alzheimer disease. Journal of the American Academy of Audiology, 9, 275–284.[Medline]
- Wilmo, A., & Nordberg, G. (2007). Validity and reliability of assessments of time comparisons of direct observations and estimates of time by the use of resource utilization in dementia (RUD)-instrument. Archives of Gerontology and Geriatrics, 44, 71–81.[CrossRef][Web of Science][Medline]
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