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www.audiologyonline.com
Dangers of
Not Assessing & Treating
Auditory
Disorders Prior to Diagnosing Alzheimer’s in Older Adults
By Max Stanley
Chartrand, Ph.D. (Behavioral Medicine)
DigiCare Hearing
Research & Rehabilitation
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 host of causal or
co-occurring factors, including disease-causing genetic mutations,
subdural hematoma, chronic hypothermia, vitamin B-12 deficiency, 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 AD,
or as an overlay factor could certainly cause overdiagnosis of AD—that
should also be on the list, but rarely is, is unmitigated hearing
impairment in older Americans.
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
alone 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 can be 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 given
before a true and 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.
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 AI (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
(below), 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.
Figure 2.
Prevalence of hearing impairment in the various age-group populations.
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 and AD in the general population track similarly in
age-group distribution (see Figure 3 below).
Figure 3-
Prevalence of AD in the various age-groups.
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 managing
director for DigiCare Hearing Research & Rehabilitation. 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:
(719)676-3277 or by email at
www.digicare.org.
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