What is an audiogram?
An audiogram is a chart which displays information about a person's hearing abilities. A person's hearing is tested by an audiologist and then plotted onto a chart which has the loudness of the sound, measured in decibels (dB), shown vertically on the left side and the frequency or pitch of the sound across the top, measured in Hertz (Hz). The dB are listed from top to bottom starting with 0 and usually stops at 120 dB. The frequency starts on the left side with 125 cycles per second (Hz) and goes up to 8000 cycles per second (Hz).
How to interpret an audiogram:
A person can be tested two different ways and both ways can be plotted on the audiogram. One testing method is Pure Tone Testing and the other is Bone Conduction. Pure tone testing, also called the air conduction test, uses headphones in which tones are sounded off in each of the ears. The child or person is then instructed to raise either a right or left hand depending on which ear the sound was in. The audiologist then plots the information for each ear onto a graph. The left ear is marked by an "X" and the right ear is marked by an "O."
Bone conduction testing occurs by directly stimulating the inner ear and bypassing the outer and middle ear altogether. A little microphone is placed behind the ear and the sound enters the skull through the mastoid bone. The test is conducted with the raising of the hands when a sound is heard. This test is plotted on the graph using triangular brackets. This bracket '<' is for the right ear, and this one '>' is for the left ear.
When both tests have been completed and plotted onto the chart, the person's hearing or loss of hearing can be identified. The chart shows the different decibel losses for each ear and at which frequencies. The person's loss is usually stated in terms of the one type of loss to another. For example: a mild to moderate loss or a moderate to profound loss.
Examples of Audiograms:
Example 1:
The following is an example of an audiogram of a child who has a mild to moderate hearing loss in both ears:
Source: Exceptional Children: An Introduction to Special Education (fifth edition) William L. Heward, Prentice-Hall, Inc. 1996
41 to 55 db (mild loss)
Effects On Understanding Language and Speech:
· Understands conversational speech at a distance of 3 to 5 feet (face to face) · May miss as much as 50% of class discussions if voices are faint or not in line of vision · May have limited vocabulary and speech irregularities
Probable Educational Needs and Programs:
· Should be referred for special education evaluation and educational follow- up · May benefit from individual hearing aid and training in its use · Favorable seating and possible special education supports, especially for primary-age children · Attention to vocabulary and reading · May need speechreading instruction · Speech conversation and correction, if indicated.
Example 2:
The following example is of a child who has a moderate to severe hearing loss:
Source: Exceptional Children: An Introduction to Special Education (fifth edition) William L. Heward, Prentice-Hall, Inc. 1996
71 to 90 db (severe loss)
Effects On Understanding Language and Speech:
· May hear loud voices about 1 foot from the ear · May be able to identify environmental sounds · May be able to discriminate vowels but not all consonants · Speech and language likely to be impaired or to deteriorate · Speech and language unlikely to develop spontaneously if loss is present before 1 year of age
Probable Educational Needs and Programs:
· Likely to need a special education program for hearing-impaired children, with emphasis on all language skills, concept development, speechreading, and speech · Needs specialized program supervision and comprehensive supporting services · Can benefit from individual hearing evaluation · Auditory training on individual hearing evaluation · Part-time regular class placement as profitable for students
