Volume 8 Issue 3 (pdf) - Andrew John Publishing Inc

| seMinars on audition
When the Brain Gets Hard of Hearing:
Paying Attention to Cognition in
Hearing Rehabilitation
By Marilyn Reed, MSc
mreed@baycrest.org
About the Author
Marilyn Reed, MSc, is the practice advisor for audiology at Baycrest, a geriatric care and
research center in Toronto, where she has worked since 1997. Marilyn graduated with a
master’s degree in audiology from the University of Southampton in England in 1976, and has
since worked in clinical audiology in a variety of settings, always with a geriatric interest.
Alzheimer’s disease, the most
common form of dementia, has
become the primary public health
concern in Canada. It is the leading cause
of disability among Canadians over the
age of 65, already costs billions of dollars
each year, and prevalence is predicted to
double worldwide within 20 years. 1
Dementia cannot be prevented or cured,
and there is an urgent need to find ways
to delay the onset and progression of the
disease and reduce the associated social
and economic costs.
Since hearing loss and cognitive
impairment are both highly prevalent in
older adults, dual impairments are
common. However, hearing loss is more
prevalent in those with dementia than in
matched control. 2 The link between agerelated
hearing loss and cognitive
impairment has been well-established
through over 30 years of research, but
recent epidemiological findings show
that older adults with hearing loss are
more likely to develop dementia, and the
more severe the hearing loss, the greater
the risk. 3 Longitudinal studies have also
shown a close correlation between
central auditory processing (CAP)
problems and cognitive impairment,
with scores on dichotic speech tests being
predictive of the likelihood of cognitive
decline. 4,5
The specific mechanisms underlying the
association between audition and
cognition are unknown; theories include
the possibility of a common cause, due
to age-related pathological changes in the
brain, or a causal relationship, with
hearing loss being a modifiable risk factor
for cognitive decline. Possible causal
pathways might involve the additional
burden that hearing loss places on
declining cognitive resources needed for
information processing, or the lack of
cognitively stimulating interaction and
social isolation resulting from sensory
deprivation.
Whatever the mechanism, the evidence
strongly suggests that hearing loss may
contribute to or accelerate the
progression of symptoms of cognitive
decline in older adults. If management of
hearing loss could reduce or delay the
progression of dementia, the implications
for the cognitive health of older adults
and the costs of dementia to public
health and society as a whole are huge.
Audiologists need to be aware of the
role that cognition plays in the
communication problems of our clients
so that we can begin to apply recent
research findings to improve both
assessment and management. While it
may be obvious which clients have more
advanced dementia, milder cognitive
impairment is difficult to recognize in
only one or two visits, and yet can have a
significant impact on the success of our
interventions. A “snapshot” of the
cognitive status of randomly selected
Baycrest audiology patients over the age
42 CANADIAN HEARING REPORT | REVUE CANADIENNE D’AUDITION