Structured Abstract
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
These recommendations were finalized by the Task Force in March 1994
Contents
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".
Recommendations were graded as:
|
A
|
Good evidence to support the recommendation that the condition
be specifically considered in a PHE. |
|
B
|
Fair evidence to support the recommendation that the condition
be specifically considered in a PHE. |
|
C
|
Poor evidence regarding inclusion or exclusion of the condition
in a PHE, but recommendations may be made on other grounds. |
|
D
|
Fair evidence to support the recommendation that the condition
be specifically excluded from consideration in a PHE. |
|
E
|
Good evidence to support the recommendation that the condition
be specifically excluded from consideration in a PHE. |
Quality of evidence was rated according to 5 levels:
|
I
|
Evidence from at least 1 properly randomized controlled
trial (RCT). |
|
II-1
|
Evidence from well-designed controlled trials without randomization. |
|
II-2
|
Evidence from well-designed cohort or case-control analytic
studies, preferably from more than 1 centre or research group. |
|
II-3
|
Evidence from comparisons between times or places with
or without the intervention. Dramatic results in uncontrolled experiments
could also be included here. |
|
III
|
Opinions of respected authorities, based on clinical experience,
descriptive studies or reports of expert committees. |
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
(patient repeats 6 words whispered to him/her at a
set distance away & out of field of vision) |
80% - 100% |
82% - 89% |
Tuning fork test
(failure to hear vibrating 512 Hz fork 1 foot away) |
80% |
65% - 82% |
Finger rub test
(rub thumb and forefinger together, slowly withdraw
until patient no longer can hear) |
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
Other
-
Canadian Task Force on the Periodic Health Examination. The periodic health
examination. 2. 1984 update. Can Med Assoc J. 1984;130:1279-80.
Link to Full Text of this
review
Link to Summary Table of Recommendations of this review
Link to Selected References list of this review
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