Prevention of Hearing Impairment and Disability in the
Elderly
Prepared by Christopher Patterson, MD, FRCPC,
Professor and Head, Division of Geriatric Medicine, McMaster University,
Hamilton, Ontario
Objective
To make recommendations about screening for hearing impairment in elderly
persons in Canada. Hearing impairment is defined as functional limitations
measured by raised hearing threshold (decibels of hearing loss relative
to the hearing of a normal population, at frequencies of 250, 500, 1000,
2000 and 4000 Hz). Hearing disability refers to limitations associated
with performance of everyday tasks (e.g., understanding speech in presence
of background noise). This updates a 1984 report.
Burden of Suffering
Hearing impairment refers to limitation of function as measured by
raised hearing threshold, measured as decibels of hearing loss (dB HL)
relative to the hearing of a normal population, at specific frequencies.
Hearing disability refers to the limitation in performing everyday tasks
such as understanding speech in the presence of background noise. Age-related
hearing loss (presbycusis) is a common phenomenon, due to a variety of
causes including sensorineural hearing loss, infectious diseases of the
middle and inner ear, noise exposure, and damage to the auditory nerve.
Presbycusis causes difficulties in sensing speech of higher frequencies
(above 1000 Hz), resulting in family and caregivers attributing misunderstanding
to confusion, forgetfulness, or inattention. By preventing effective communication,
hearing loss can affect physical, emotional, cognitive, behavioural, and
social functioning.
At least 25% of individuals over the age of 65 report hearing problems,
while audiologically detectable hearing loss (HL) is present in more than
one-third of all people over that age. The prevalence of hearing loss is
even greater in institutions. Hearing impairment is associated with diminished
function in the elderly. For example, in a case series of older individuals
screened in primary care practice, a 10 dB increase in hearing loss was
associated with a 2.8 point increase in physical Sickness Impact Profile
scores. Hearing impairment is associated with more rapid decline in cognitive
function in people with Alzheimer's diseases. Even mild hearing loss is
associated with memory failure.
Options
Screening options were single questions; a 10-item version of the hearing
handicap inventory for the elderly (HHIE-s), physical tests (whispered-voice
test, tuning fork test, finger-rub test), and pure tone audiometry. Preventive
and treatment measures included noise control programs and hearing protection,
referral to a specialist, hearing aids and digital signal processing.
Outcomes
Test sensitivity and specificity. Health outcomes included social and
emotional functioning, depression, communicative and cognitive abilities,
and intelligibility.
Evidence
MEDLINE was searched from 1988 to March 1993 using the keywords "presbycusis",
"aged" and "middle age".
Values
The 13-member Task Force of experts in family medicine, geriatric medicine,
pediatrics, psychiatry and epidemiology used an evidence-based method for
evaluating the effectiveness of preventive health care interventions. Recommendations
were not based on cost-effectiveness of options. Patient preferences were
not discussed.
Background papers providing critical appraisal of the evidence and tentative
recommendations prepared by the chapter author were pre-circulated to the
members. Evidence for this topic was presented and deliberated upon in
1- to 2-day meetings, 2 to 3 times per year from January 1993 to June 1993.
Consensus was reached on final recommendations.
Benefits, Harms, and Costs
Properties of screening tests reported in case series are summarized
below.
|
Test
|
Sensitivity
|
Specificity
|
| Single question ""Would you say
that you have any difficulty hearing?" |
90% for detecting a 40db HL
at 1000 and 2000 kHz
83% for detecting 40 db HL at 1000 and 4000 Hz in
better ear |
71%
75% |
| HHIE-S |
65% - 75% |
75% - 82% |
| Whispered-voice test |
80% - 100% |
82% - 89% |
| Tuning fork test |
80% |
65% - 82% |
| Finger rub test |
80% (failure to hear at 6-8
inches)
80% (failure to hear at 3 inches) |
49%
85% |
| Audioscope |
87% - 96% |
70% - 90% |
In an RCT of 194 elderly male veterans, patients randomly allocated to
hearing aids had significant improvements in social and emotional functioning,
depression scores, communicative and cognitive abilities at 6 weeks and
4 months compared with those allocated to waiting list. Studies of digital
signal processing report a 10% to 12% improvement in intelligibility among
patients with moderate sensorineural hearing loss, but no improvement for
those with severe hearing loss. Only about 50% of patients accept amplification.
Cohort analytic studies have found an unequivocal relationship between
noise exposure and hearing loss.
Recommendations
Recommendation grade [A, B, C, D, E] and level of evidence
[I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations
in support of individual recommendations are identified in the guideline
text.
-
There is fair evidence to screen for hearing impairment in the PHE of elderly
persons [B, I, III].
-
There is good evidence to support noise control and hearing protection
programs [A, II-2].
Validation
This report was externally peer reviewed. The 1989 US Preventive Services
Task Force recommended evaluation of hearing, counselling regarding hearing
aid use, and referral for abnormalities.
Sponsors
The Canadian Task Force on Preventive Health
Care developed this guideline with funding from Health Canada.
Selected References
Source Document
Patterson C. Prevention of hearing impairment and disability in the
elderly. In: Canadian Task Force on the Periodic Health Examination. Canadian
Guide to Clinical Preventive Health Care. Ottawa: Health Canada,
1994; 954-63.
Other
Canadian Task Force on the Periodic Health Examination. The periodic
health examination. 2. 1984 update. Can Med Assoc J. 1984;130:1279-80.