Dangers of Not Assessing & Treating Auditory Disorders Prior to Diagnosing Alzheimer's in Older Adults

By Max Stanley Chartrand, Ph.D. (Behavioral Medicine)

Vignette: The children of 87 year-old Mrs. Anna Smith are concerned about her mental health. She lives alone, and although no major mishaps have occurred, they are concerned that she is becoming reclusive and depressed. At family gatherings, she sits off to the side of the group and no longer participates in conversation. At times, family members attempt to include her, but responses are so inappropriate and off-subject that they are embarrassed to keep trying. Upon taking her to see their family physician, she is immediately placed on antidepressant medication. The medication causes her to be anxious and to stay up all hours, so antianxiety medication is added. She is then referred to a local psychiatrist, who administers the auditory-based Mini-mental State Examination (MMSE) battery and CES-D test. On the MMSE she is scored with 10 errors, indicating moderate Alzheimer's disease (AD). Her CES score is 18, indicating elevated risk for clinical depression. The children are distraught over the diagnoses, but conclude that their own observations coincide with the doctors'. Plans are made to take Power of Attorney over her real and personal assets, and to admit her for residency in a nearby nursing home.

Alzheimer's Disease: At Best, a Difficult-to-Diagnose Condition

According to recent research, the symptoms of Alzheimer's disease (AD), a degenerative form of mental illness, can be caused by a host of causal or co-occurring factors, including disease-causing genetic mutations, subdural hematoma, chronic hypothermia, vitamin B-12 deficiency, chronic dehydration, adverse drug interactions, mercury or manganese poison, Huntington's disease, dementia with lewy bodies, alcoholism, and even Mad Cow disease (Rait et al, 2005; Adviware, 2005; Blackwell et al, 2004; Lawrence et al, 2003). Another condition—the symptoms of which could be mistaken for mild and moderate AD when overlaid with normal aging factors in older adults---should also be on the list, but rarely is: untreated hearing impairment.

Consequently, AD is an enormously difficult condition to diagnose for even the best trained professionals. In fact, researchers at Columbia-Presbyterian Hospital in 1996, in a post-mortem investigation of patients previously diagnosed with AD, found a 45% misdiagnosis rate (Alzheimer's Foundation, 2005). In addition, normal age-related cognitive changes have been implicated in cases of misdiagnosis and overdiagnosis of AD, signaling the need for better and more accessible, cost-effective diagnostic methodologies ((National Institute on Aging, 2002). 

But, just as the lack of an evaluation for auditory function was lacking in the vignette above, it is usually found missing in most cases of diagnosis of AD in elderly individuals who may or may not suffer from unmitigated hearing impairment (Chartrand, 2001b; Ullman et al, 1989; Peters, Potter, and Scholar, 1988). Other cognitive conditions, such as depression, anxiety, and anti-social behaviors caused by uncorrected hearing loss have also been thoroughly documented in the literature (Chartrand, 2001a). Yet, in the above vignette, hearing status was apparently disregarded by family and health professionals, each of whom have made decisions critical to the well-being of the patient in question.

Moreover, the most commonly used screening examination, the Mini Mental State Examination (MMSE), as well as the Sternberg Memory Scan and California Verbal Learning Test are all administered verbally to older adults (Dumont and Hagberg, 1994). These tests assume normal hearing acuity as well as normal central auditory processing ability—two separate and distinct areas of concern—in a demographic age-group fraught with auditory lesions to varying degrees. It is the thesis of this paper that any clinical assessments for cognitive function in older adults must begin with a complete and thorough audiological assessment. Furthermore, if an auditory deficit is found, auditory rehabilitation should be provided before a valid assessment of cognitive function can be rendered (see Figure 1).

Figure 1- Symptomatic comparison between moderate Alzheimer's disease and untreated hearing loss. The differences are so subtle that even the best trained professionals have difficulty differentiating.

Symptomatic comparison: AD & HL

Pervasive Lack of Awareness about AD-Auditory Connection

A pervasive lack of public and professional awareness of the importance to first ascertain auditory status before assessing cognitive status in older adults is further reinforced by publications, such as The Caregiver Handbook (Area Agency on Aging, 2004). In its otherwise excellent 224 pages is found good advice about caring for those suffering with dementia. However, no where in its pages are found anything about audiology, audiologists, hearing aids, hearing specialists, hearing impairment, or the cognitive effects of uncorrected hearing loss and need to ascertain such. The section titled "Communicating with someone who has dementia" reads like instructions in dealing with someone with severe hearing impairment, yet the possibility of an existing or undetected hearing impairment is not mentioned.

Likewise, graduate-level textbooks dealing with memory, cognition, geriatrics and eldercare fail to relate the link between cognitive function in older adults and hearing impairment (Schultz & Salthouse, 1999; Matlin, 2002). From public to professional, from diagnosis to treatment, and from government regulatory agencies to research institutions, the issue of such relationships appears non-existent. Indeed, as this author has asserted time and again: Hearing impairment is an invisible handicap, yet its effects upon one's personal health, happiness, and personal well-being are very real.

Prevalence & Complexity of Auditory Deficits in Older Adults

The types of auditory disorders that form the paradigm of presbycusis, or auditory deficits that appear in old age are numerous and most complex (Stary, 2002; Surr, 1977; Pearlman, 1982; Willot, 1981; Halpern, Keith, and Darley, 1976). Just a few of the auditory age-related conditions that can co-occur are:

• Epithelial, cartilaginous and bony distortions of the external meatus
• Tympanosclerosis and otosclerosis of the middle ear
• Otosclerosis of the cochlea and vestibular labyrinth
• Circulatory constrictions in the stria vascularis
• Diplacusis, hyperacusis, abnormal loudness growth, and other cochlear distortions due to loss of hair cells and tip-links
• Loss of synaptic and neuronal activity in the spiral ganglia
• Auditory neuropathy (especially in diabetes mellitus II)
• Palsies and auditory neuroma affecting Cranial VII & VIII
• Central auditory processing disorders (i.e., superior olivary complex)
• Cortical atrophy (re sensory deprivation) and other processing deficits

These and other overlay conditions can present challenges, such as abnormal loudness growth, perceptual distortions, cognitive dysfunction, inappropriate social behaviors, and many physiological and neurological aberrations within the human hearing system that can be difficult to assess and to correct (Stach, Spretnjak, and Jerger, 1990; Schuknecht, 1974). Moreover, it is widely understood in the field of hearing sciences that long-standing unmitigated hearing losses in the elderly can produce a temporary central auditory deficit condition known as phonemic regression.

Phonemic regression is evidenced by amplified speech recognition scores (i.e., corrected to optimal threshold levels) that result significantly below what would be expected for a given hearing loss. Utilizing the template of the Articulation Index (AI) in assessing what a given correction can be expected in terms of improved audition, we find many older first time hearing instrument users having difficulty meeting those expectations in the early stages of rehabilitation. Most require an auditory rehabilitative period of up to 90-120 days to reach expected levels of performance as measured on the Articulation Index (AI)

Figure 2 Distribution of Alzheimers by Age Figure 3. Distribution of Hearing Loss by Age.

(Chartrand, 1999; Tyberghein, 1996; Gatehouse and Killion, 1993). (As a side-note: This is one of the major reasons this author frequently expresses concern re state laws requiring 30-day trials of hearing aids, as such laws utterly disregard auditory rehabilitative principles, and spawn a growing population of "failed" hearing aid users and add considerably to negative images of hearing aids, in general).

Furthermore, the possibility of phonemic regression in an older adult with long-standing and untreated hearing impairment particular salient to our discussion here, for a verbal exam for memory and/cognition could be highly inaccurate. This fact becomes of particular concern when one considers that the market penetration for those who have been diagnosed with various dementias is several times less than the non-demented population (Chartrand, 2001b).

From Figure 2 (above), one may compare the prevalence of hearing impairment in the different age-groups. It is noteworthy that hearing impairment becomes quite concentrated in the older population, from 36% in those 65-84 years of age to 66% or higher in those 85 years and up (Aural Rehab Concepts, 2000). Furthermore, the aging of America continues unabated, with those 85 years and older making up the fastest growing demographic age group (U.S. Census Bureau, 2005). Hence, the rapid increase in the older adult population tracks closely with rapid increases in hearing impairment prevalence in the general population.

In addition, there has been a steady decline in the percentage of those utilizing hearing aids, cochlear implants, and assistive devices relative to the increased numbers of those who could benefit from them (Chartrand and Chartrand, 2004). Of course, many of these unmitigated cases are going to be evaluated for a host of other health conditions requiring normal auditory skills to render valid assessments. However, the prevalence of hearing loss in the general population track similarly in age-group distribution (see Figure 3 above).

Referral-Treatment Pathways for Late Onset AD

As evidenced above, it becomes an ethical and moral imperative for mental health professionals to ascertain the auditory status of the older adult before concluding diagnosis or proceeding with treatment of cognitive/memory disorders. To do this, however, requires community-based teamwork among allied health professionals. Following is an flow-chart explanation of how a patient with suspected AD might be referred and treated (see Figure 4 below):

• Entry into the system usually begins with a concerned family member. They, in turn, usually start the process with an examination by the primary care physician (PCP). 
• The PCP, after addressing general medical/health aspects, such as medication side-effects, underlying physical disease, and/or identifiable stressors, should then refer for otological and audiological examination from otolaryngology/audiology practitioners. 
• If, after the appropriate battery of tests, said patient does exhibit otologic or audiologic conditions, these should ideally be addressed before commencing with cognitive assessments (exceptions to this would in cases where an urgent situation requires immediate attention).
• Referral to a neurologist and a psychiatrist may ascertain/treat other overlay issues, such as stroke, TIA, and/or neurological issues.
• Other rehabilitative specialists that may enter at this point is the audiologist (auditory rehabilitation), speech pathologist (speech/language therapy), and/or occupational therapist.
• Institutions that may become involved at various points in our flow-chart might be the hospital (acute care), nursing facility (intermediate care), and home health care (stabilized, general care).

Figure 4- Though AD patients come through varying referral "doors", the ultimate pathways for assessment and treatment should vary little.

Of course, caregivers, especially family members, play an important and ongoing role throughout all the above. Their role in vitally important in assuring that the patient receives hearing help and access to auditory rehabilitative resources, and to help assure the proper order of the above flow-chart.

For instance, caregivers should be particularly interested in assuring that conclusive diagnosis resulting from verbal tests is not taken seriously until the patient's hearing health has been addressed. They, in a very real sense, become quality assurance (QA) for advocacy, care and treatment of the patient. To do less, risks over-medicating, under-treating, and/or making an otherwise temporary problem become an irreversible permanent one.

About the author…

Dr. Chartrand serves as Associate Professor in Behavioral Medicine at Northcentral University and Director of Research for DigiCare Hearing Solutions, INc. in Colorado City, CO. He is profoundly deaf and utilizes a cochlear implant. As a widely published author and educator in the hearing field he brings unique insights into the assessment and treatment of the hearing impaired. Contact:



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