Causes

Occupational hearing loss is a form of acoustic trauma caused by exposure to vibration or sound. Sound is heard as the ear converts vibration from sound waves into impulses in the nerves of the ear.

Watch this video about:Hearing and the cochlea

Sounds above 90 decibels (dB, a measurement of the loudness or strength of sound vibration) may cause vibration intense enough to damage the inner ear, especially if the sound continues for a long time.

• 90 dB -- a large truck 5 yards away (motorcycles, snowmobiles, and similar engines range from 85 - 90 dB)
• 100 dB -- some rock concerts
• 120 dB -- a jackhammer about 3 feet away
• 130 dB -- a jet engine from 100 feet away

A general rule of thumb is that if you need to shout to be heard, the sound is in the range that can damage hearing.

Some jobs carry a high risk for hearing loss, such as:

• Airline ground maintenance
• Construction
• Farming
• Jobs involving loud music or machinery

In the U.S., the maximum job noise exposure is regulated by law. Both the length of exposure and decibel level are considered. If the sound is at or greater than the maximum levels recommended, protective measures are required.

Symptoms

The main symptom is partial or complete hearing loss. The hearing loss may get worse over time with continued exposure.

Sometimes hearing loss is accompanied by noise in the ear (tinnitus).

Exams and Tests

A physical examination will not usually show any specific changes. Tests that may be performed include:

• Audiology/audiometry
• CT scan of the head
• Head x-ray

Treatment

The hearing loss is usually permanent. The goal of treatment is to prevent further hearing loss, improve communication with any remaining hearing, and develop coping skills (such as lip reading).

Using a hearing aid may improve communication. Always protect the ear from further damage. For example, wear ear plugs in noisy areas.

Outlook (Prognosis)

Hearing loss is often permanent in the affected ear. The loss may get worse if you don't take measures to prevent further damage.

Possible Complications

Hearing loss may progress to total deafness.

When to Contact a Medical Professional

Call for an appointment with your health care provider if:

• You have hearing loss
• The hearing loss gets worse
• You develop other new symptoms

Prevention

• Protect your ears when you are exposed to loud noises. Wear protective ear plugs or earmuffs to protect against damage from loud equipment.
• Be aware of risks connected with recreation such as shooting a gun, driving snowmobiles, or other similar activities.
• Do not listen to loud music for long periods of time, including using headphones.

Alternative Names

Hearing loss - occupational

References

Lonsbury-Martin BL, Martin GK. Noise-induced hearing loss. In: Cummings CW, Flint PW, Haughey BH, et al, eds. Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, Pa: Mosby Elsevier;2010:chap 151.

Updated: 4/3/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, Unviersity of Washington School of Medicine; and Seth Scwartz, MD, MPH, Otolaryngologist, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.