Hearing Testing and Hearing Impairments

Hearing testing is an important tool for identifying hearing loss. A hearing test is either completed as a preventative measure, or in response to a suspected hearing problem. Hearing screening and testing are particularly important in children, as hearing loss can lead to speech impairments. A person's daily routine can be affected significantly by hearing impairments. Testing can help to identify a hearing problem early so measures can be taken to manage hearing loss.

Hearing Testing

Hearing testing can take on several different methods:

• Hearing screen: A brief test of a few frequencies to determine whether hearing thresholds (lowest levels at which sounds can be perceived) appear to be within normal limits. If a person does not pass the screen, more in-depth testing is often recommended.
• Pure-tone hearing test: A test to determine thresholds of hearing for single-frequency tones, usually between 250 and 8000 Hz. Results are displayed on a chart called an "audiogram."
• Speech testing: Testing of hearing thresholds for word recognition to determine whether an individual has difficulty hearing speech, and to determine the best level of presentation or amplification if there is a hearing loss.

Hearing screens may be conducted in schools, or in senior citizen centers. For full hearing testing, you will need to be referred to an audiologist, a health professional specializing in hearing and hearing loss.

Types of Hearing Impairment

Hearing loss refers to loss of hearing acuity, or ability to transmit sound at some level of the hearing mechanism. Sound is transmitted in two ways:

• Air conduction: Sound waves can be taken in from the air and be transmitted through the hearing structures in the ear.
• Bone conduction: Bones in the head, including the skull across the forehead and the mastoid bone (the bone behind the ear) can transmit vibrations, which are processed as sound.

Either of these methods of hearing may be damaged in people with hearing loss. Testing may reveal one of three types of hearing loss:

• Conductive hearing loss: Air conduction is impaired and bone conduction remains within the normal range.
• Sensorineural hearing loss: Air conduction and bone conduction are affected, as the affected part of the hearing mechanism is in the cochlea or auditory nerve.
• Mixed hearing loss: A combination of conductive and sensorineural hearing loss.

Hearing testing will help to determine the type of hearing loss, the degree of loss (how far thresholds fall below the normal range), and the specific effects on particular frequencies, known as the "configuration" of the hearing loss. Results are shown on the audiogram, which has specific symbols to denote right and left ears, as well as air and bone conduction thresholds. Your audiologist can explain the meaning of the information on the audiogram.

Causes of Hearing Loss

Hearing loss can be attributed to a variety of causes, including:

• Disease or infection (such as measles or meningitis)
• Excessive noise exposure at dangerous levels
• Injury (such as puncture of the tympanic membrane)
• Presbycusis (age-related hearing loss).

If you think you or a loved one may be experiencing hearing loss, test options are available. Contact your doctor for a preliminary hearing screen, or a referral to an audiologist for specialized testing.

Resources

Allen, D. (n.d.). Understanding your hearing test. Retrieved January 31, 2010, from Hearing Center Online Web site: http://www.hearingcenteronline.com/test.shtml.

American Speech-Language-Hearing Association (n.d.). Hearing assessment. Retrieved January 31, 2010, from American Speech-Language-Hearing Association Web site: http://www.asha.org/public/hearing/testing/assess.htm.