Hearing Conservation for the Primary Care Provider
Briefing Outline
- Role of Audiologist in Health Care
- How Common is Hearing Loss?
- Fundamental Concepts of Hearing Conservation
- Prevention of Noise-Induced Hearing Loss
- Audiogram Interpretation
Professional Supervisor
- Audiologist in Health Care
- Mission of Base Audiologist
- Role of Professional Supervisor in Occupational Hearing Conservation
Demographics of Hearing Loss
- Hearing Loss is the third chronic health condition in the older
population
- 28 million people or 10 percent of population
- 10 million - noise-induced hearing loss
- Rate of hearing loss is increasing in all age groups
National Health Interview Survey, US
Age Group
Male and Female |
Percent hearing loss |
Increase in Hearing Trouble
(from 1971-1991) |
| 3-17 |
5% |
12.3% |
| 18-44 |
4.6% |
17.1% |
| 45-64 |
14% |
26.0% |
| 65+ |
54% |
6.0% |
Culture of Noise
- 356 subjects, 18-25 years old
- 18.8% social activites
- 3.5% occupational
- 2.9% gunfire
- 1364 subjects, 14-25 years old
- Significant hearing loss for personal stereo use 7+ hours/week or 2
concerts/month
- 50 subjects, 18-30 years old
- users of personal stereo use at low risk for noise-induced hearing
loss
Fitness Clubs
- Measured at 90 clubs across US
- Levels reached 120 dB
- 80% reached 105 dB for 1-hour classes
- Hess center, Aerobic Class in Bubble
- Levels reached 97 dBA for participants
- Walkers exposed to 87 dBA
Movies
- Armageddon 117-118 dB Shuttle Lift-Off
- Godzilla 112-115 dB Godzilla shriek
Concerts
- Standard level at rock concerts is 126 dB
- Professor of Music History at Princeton
- Suing the Smashing Pumpkins
- 4% hearing loss at one concert despite using hearing protection
Non-occupational noise levels
| Source |
dB SPL |
| normal conversation |
65 |
| normal traffic |
70-95 |
| lawn mowers |
85-90 |
| power tools |
90 |
| personal stereo |
95-115
|
| leaf blower |
105 |
| rattles/squeaky toys |
110 |
| chain saw |
118 |
| toy cap gun |
163 |
Goal of a Hearing Conservation Program
To reduce the risk of developing a permanent noise-induced hearing loss
Reach Goal with Damage Risk Criterion
The purpose of a damage risk criteria is to define maximum permissible
levels of noise for stated duration whic, if not exceeded, would result in an
acceptably small effect on hearing levels over a working lifetime of
exposure.
The Damage Risk Criterion Used
- Air Force
- 85 dBA Time Weighted over 8 hours (TWA)
- 3 dB exchange rate
- OSHA
- 90 dBA Time Weighted over 8 hours (TWA)
- 5 dB exchange rate
Risk of Sustaining Hearing Handicap
OSHA - 90 dB TWA, 15% expected impairment, three million
workers with hearing handicap after 40 years.
USAF - 85 dB TWA, 5% expected impairment, one million
workers with hearing handicap after 40 years.
Elements of a Hearing Conservation Program
- Noise Measurement and Engineering Controls
- Audiometric Testing
- Employee Training and Education
- Record Keeping
- Program Evaluation
Teach Your Patients
- Each person must take positive action to prevent noise-induced hearing
loss
- Prevention is accomplished by reducing both the time and
intensity of noise exposure
- Teach the three-foot rule
The Cochlea
Photomicrographs of 4000 Hz region of
the cochlea in a control (non-noise exposed, left) and a noise-exposed animal,
(right).
Understanding the Audiogram
Please see information provided by the American Academy of
Audiology (AAA) website.
Noise-Induced Hearing Loss
- progresses slowly
- loss is first measured between 3000-6000 Hz
- presents a characteristic known as noise notch
- over time the notch becomes deeper and broader
- as more frequencies become involved, more communication difficulty
develops
- "I can hear people speaking but can't understand what they're saying."
Audiogram of Familiar Sounds
Please see the AAA website for further information about this chart.
Hearing Protection Devices
- earplugs
- earmuffs
- custom molded devices
Tympanograms
- Type A - normal middle ear status
- Type B - can be due to effusion
- Type C - can be due to eustachian tube dysfuntion
Credits
Maj Linda Ruckriegel, USAF
75 AMDS/SGPMA
Hill AFB, UT
