Hearing Loss and Aging: Implications for Audiologists
Pamela Souza, PhD,
Our population is getting older. Much older. In the 2010 census,
nearly 1 in 5 adults in the United States was over 60 years of age. Over the
next 30 years (the likely career span of an audiologist), the percentage of the
population over 65 is expected to double, and the population over 85 is
expected to triple. Older adults are not only living longer, but working
longer and staying socially active later in life. In other words, their
communication needs are greater than ever. The rate at which these adults seek
help is likely to increase, driven by their communication needs and by improved
access to health care. Older adults' comfort level with technology is also
increasing (Wandke, Sengpiel, & Sönksen, 2012). Most clinical audiologists
have long served the aging population, but are now poised for a transition in
what aging means to audiology practice.
Age-related hearing loss is not
inevitable, but it is a common consequence of aging. Presbycusis (age-related
hearing loss) may be coupled with noise exposure, illness, or use of ototoxic
medications that have occurred over many years of life. Recent studies recognize
an association between hearing loss and diabetes (Horikawa et al., 2013) and
between hearing loss and vascular disease (Lee, 2013), each of which occurs at
much higher rates in older adults. Even using relatively narrow definitions, we
can estimate that hearing loss affects up to 40% of adults over 65 years, 60% of
adults over 75, and 80% of adults over 85 years (Cruickshanks, Tweed, Wiley,
Klein, Chappell, et al., 2003; Gates, Cooper, Kannel, & Miller, 1990;
Reuben, Walsh, Moore, Damesyn, & Greendale, 1998). Simply put, the majority
of older adults have some hearing difficulty, and the consequences of that
difficulty can be substantial. Hearing loss is associated with depression
(Gopinath et al. 2012; Savikko, Routasalo, Tilvis, Strangberg, & Pitkala,
2005), reduced employment prospects (Kyle & Wood, 1985), and family stress
(Scarinci, Worrall, & Hickson, 2008). Due to their appointment constraints
and training, primary care physicians may play a minimal role in hearing loss
identification and treatment. Audiologists connect the patient to support,
information, and appropriate rehabilitative options. Because good communication
requires cooperation from both talker and listener, audiologists also provide
community education, especially in regard to hearing and accommodations in
public spaces. To provide full-service treatment, audiologists must understand
the context of age-related hearing loss.
Healthy Aging and Cognitive
Age, as they say, brings wisdom, and many cognitive abilities
are honed throughout our lives. Wisdom and creativity continue to the end of
life. Daily occupational and social functioning is not impaired by normal aging.
Most aspects of language ability remain strong, and some (such as the ability to
draw information from context) offer compensatory choices that can offset other
declines (Pichora-Fuller, 2008). However, even healthy aging is often
accompanied by cognitive changes. Long-term memory may decline. The rate at
which new information is learned can be slower, and older adults often have a
greater need for repetition of new information. Examples of specific cognitive
abilities important to auditory communication include processing speed, working
memory, and executive function. Each of these abilities is necessary to
Processing speed allows the listener to take in,
evaluate, and assign meaning to a rapidly changing acoustic signal. Because the
typical speech rate is approximately four syllables per second, listeners are
taking in more than 240 chunks of phonemic information per minute. While
processing lags, the conversation has moved on, and older listeners with hearing
loss sometimes report feeling fatigued with attempts to keep up.
memory allows simultaneous processing and storage during a listening (or
reading) task and is essential to assigning meaning to what is heard. Working
memory is likely to be required to a greater extent when the acoustic signal is
degraded (Rönnberg, Lunner, Zekveld, Sörqvist, Danielsson, et al., 2013), as
occurs with background noise or reverberation, or when the listener has hearing
impairment. In that situation, the acoustic (and/or visual) input may be
ambiguous, requiring the listener to compare the input to choices within the
mental lexicon where meaning is assigned. A similar problem has been shown for
patients with low working memory who receive complex hearing aid processing that
significantly alters signal acoustics, probably because the resulting signal is
less familiar (and therefore less unconsciously processed; Arehart, Souza, Baca,
& Kates, 2013; Lunner, 2003). Taken as a whole, results of working memory
studies suggest that listeners with low working memory may perform best with
low-alteration processing that employs a slow wide-dynamic range compressor and
minimal amounts of frequency compression, provided there is good signal
Finally, executive function allows the listener to direct
attention and to ignore extraneous information, an important skill for listening
to a target talker in a background of other talkers or for switching attention
among talkers. In population studies, all three abilities decline somewhat with
age. Importantly, there is also variability among individuals.
tests are available to evaluate specific cognitive abilities, such testing is
not yet a common feature of an audiometric evaluation. In general, one might
expect an 80-year-old patient to process information more slowly, have somewhat
lower working memory, and perhaps have less ability to ignore distracting
auditory information than a 40-year-old. In caring for older patients, one
should consider how cognitive ability affects communication and learning. This
is not to suggest that older patients should be patronized, but rather that the
appointment structure and supporting materials should be designed to accommodate
the entire range of abilities in older patients.
Aging and Dementia
An unfortunate consequence of aging is an increased risk of dementia. New
guidelines from the Alzheimer's Association (Sperling, Aisen, Beckett, Bennett,
Craft, et al., 2011) present three stages of pathological cognitive change.
- It is theorized that the initial stage is a pre-clinical stage, in which
physiological changes have occurred, but significant behavioral symptoms are not
- Mild cognitive impairment (MCI) presents with memory loss or
changes to thought processes that are greater than those that occur with typical
aging, but throughout which the patient maintains independence. It is not a
foregone conclusion that MCI will progress to dementia, although that is a
possibility (Bensadon & Odenheimer, 2013).
- In Alzheimer's
dementia, memory loss, changes in behavior, impaired judgment, and difficulty
processing visual/spatial information are significant and will impair
independence. Later symptoms of the disease (albeit less likely to be seen by
clinical audiologists) include difficulty speaking, swallowing, and walking.
Less common causes of dementia (still affecting large numbers of
individuals) include dementias caused by vascular incidents, dementia with Lewy
bodies, and Parkinson's disease dementia. The prevalence of dementia is
estimated at nearly 15% of adults over 70 years of age, with higher incidence in
older age groups [PDF]. Considering the large numbers of adults affected,
audiologists are very likely to see patients at least with MCI and, often, with
dementia as well.
While patients in late-stage dementia and their
families are under a significant burden and hearing care may not be a priority,
improved communication is an important goal throughout the stages of the
disease. Inability to hear may result in new or exaggerated symptoms that are
mistakenly attributed to cognitive decline, including failure to respond or
responding inappropriately to questions. Amplification (via a hearing aid with
automatic function, if appropriate, or other assistive device) can improve
communication (Petitot, Perrot, Collet, & Bonnefoy, 2007; Durrant, Palmer,
& Lunner, 2005) and may reduce cognitive load. Physicians, speech-language
pathologists, and occupational therapists who work with patients with cognitive
disorders should be alert to a possible need for amplification and refer
Does Hearing Loss Increase Dementia Risk?
the past few years, some compelling epidemiology data have shown that hearing
loss is associated with increased risk of cognitive decline (Lin, Yaffee, Xiz,
Zue, Harris, et al., 2013) and/or dementia (Lin, Metter, O'Brien, Resnick,
Zonderman et al., 2011; Gurgel, Ward, Schwartz, Norton, Foster, et al., 2014).
The association persists even after controlling for hearing-related systemic
conditions, such as vascular or cardiac disease. The more hearing loss the
patient has, the stronger the association.
The puzzle is the source (or
sources) of the association. First, there might be some underlying physiological
or neurological change resulting in both cognitive change and hearing loss.
Although major diagnoses were considered (and adjusted for) as confounding
factors in those studies, that did not preclude more subtle systemic effects,
such as microvascular dysfunction. Second, we know that social isolation is
associated with increased risk of dementia (Holwerda, Deeg, Beekman, van
Tilburg, Stek, et al., 2012). If hearing loss leads to withdrawal from social
and family activities, the isolation itself might be the precipitating factor.
Third, hearing loss and loss of signal redundancy require that the patient
compensate through effortful listening. Such effort might deplete cognitive
resources, leading to a decline. We also have evidence that brain volume changes
as a result of hearing loss (Lin, Ferrucci, An, Goh, Doshi, et al., 2014). For
any given patient, the increased risk is relatively small. But in a population,
the issue presents a possible public health opportunity: Can early correction of
hearing loss improve the incidence of dementia? Continued research may help
untangle these factors.
The Audiologist's Role in Screening for
A minority of clinics provide formal screening for
cognitive function as part of their test battery. Simple cognitive screening
metrics are readily available, and patients of concern can be referred to their
physician for follow-up. However, in some facilities, clinic time may not permit
formal screening, or the audiologist may not feel comfortable with the
discussion of specific test results and the concerns regarding memory that might
be raised by those tests. An alternative way to consider cognition in audiology
practice is simply to be an alert provider. A recent article by Remensnyder
(2012) offers a wealth of strategies to consider. Audiologists can be alert to
aberrant communication, such as inappropriate affective reactions, or difficulty
with memory or word finding. Audiologic history should include questions about
memory (while being aware that many normally aging adults will admit to memory
concerns), depression, and history of head injury (associated with cognitive
change and increased dementia risk). Although many patients will not rise to the
level requiring medical follow-up, awareness of memory concerns (and possible
MCI) will dictate the extent of supportive audiology care.
Cognition in Hearing Aid Fitting and Training
We can support older
patients who are cognitively impaired with a variety of strategies. Family
members and communication partners should be encouraged to participate in
appointments, both for the patient's benefit and for their own information. Some
hearing aid features can ease the burden on the patient. Those features include
automatic directivity, automatic program change and telecoil activation, or
verbal prompts ("change battery" rather than a signal beep). It can be helpful
to disengage all audible alerts, except those considered essential (e.g.,
battery change) to minimize the need to discriminate and interpret signals.
Because listening in high levels of background noise is most detrimental to
listeners with poor working memory, a thoughtful approach to noise reduction is
warranted. This should include use of directional microphones and/or assistive
devices that improve signal-to-noise ratio and perhaps also use of
low-distortion digital noise reduction (Ng, Rudner, Lunner, Pedersen, &
Rönnberg, 2013). Care should be taken that assistive technology is not so
complex that it prevents ready use.
Clear, brief, written materials
(such as a quick reference card outlining the procedure for using the hearing
aid for telephone listening or a label on the hearing aid case to prompt daily
cleaning) can serve as reminders. More frequent appointments offer a chance to
check in with the patient and reinforce new skills. Optional or bundled aural
rehabilitation sessions are an excellent option to empower the patient and train
him or her on hearing aid use and good communication. Even simple
strategies—such as modifying the listening environment—may not be obvious to the
patient or family. Review and practice are essential. Remember that much of the
information provided at a health-care appointment is forgotten, and at least
half of the recalled information is incorrect (Kessels, 2003; McGuire,
To consider all practicalities, consider how changes in vision
and dexterity can impact rehabilitation. Arthritis affects as many as half of
adults over 65 years and can make it difficult to feel or manipulate small
items, such as hearing aid batteries and controls. Weakening vision reduces
reading speed and causes problems seeing in dim light, reading small print, and
locating objects. Specific vision impairments, such as cataracts and macular
degeneration, may make it impossible to read instruction manuals. Patients may
not volunteer this information, either because they aren't prompted to discuss
it or because coping with reduced sensation has become a normal (and
unremarkable) part of life.
The focused view of the audiology clinic as
a place to treat hearing is and will continue to change. Figure 1 shows the
complex interrelationship of factors associated with aging that touch clinical
care in some way. Older adults comprise ever-larger numbers of an audiologist's
patients, and those older adults have unique needs with regard to hearing,
cognition, and overall health. Priorities for those adults include health,
independence, and coping with adversity (Phelan, Anderson, LaCroix, &
Larson, 2004). Age-related cognitive change presents a special challenge.
Cognitive changes may affect communication directly—by impairing abilities that
are drawn on in difficult listening—or indirectly—by changing the ability to
adapt and to engage in social activities. The social milieu may also be
different for older adults. Sixty-four percent of older Americans ages 65–74 are
married and live with a spouse. After age 85, only 24% live with a spouse, and
half live alone. Changes to social support —such as widowhood—can adversely
affect health outcomes (Bisconti & Bergeman, 1999). The audiologist can be
most effective by considering the patient's lifestyle, needs, interests, and
challenges; by listening attentively; and by using that information to provide
customized and responsive treatments.
The author's work is supported by the National Institute on Deafness and
Other Communication Disorders (R01 DC60014 and R01 DC12289). The author thanks
Kathryn Arehart, Thomas Lunner, Linda Remensnyder and Jing Shen for helpful
conversations regarding aging, cognition, and patient care.
Pamela Souza is a professor at Northwestern University.
Throughout her career, she has combined academic teaching and research with work
as a clinical audiologist. She has worked with patients ranging from pediatric
to geriatric populations. She directs a longstanding research program in effects
of hearing aids, particularly for older listeners and those with severe hearing
loss. Her interests include use of signal-processing amplification, which
affects acoustic speech cues, how those changes interact with listener age and
cognitive status, and how research findings in this area can direct clinical
practice. Dr. Souza is a Fellow of the American Speech-Language-Hearing
Association. Contact him at email@example.com.
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