The hearing test

Hearing testing must be performed in a sound-isolated booth. Any noise can interfere with the child’s ability to detect very soft sounds so the testing cannot be done in a classroom, therapy room, or physician’s office.

A specialized piece of equipment called an audiometer is used to test hearing. The audiometer presents controlled and calibrated stimuli to the child to determine the softest level or “threshold” at which the child can hear sound. The tones are presented by the audiologist from low pitch to high pitch to each ear, one at a time. The audiologist makes the tones softer and softer until the child is just barely able to hear it to the threshold.

As the audiologist performs the tests, the results of the child responses are recorded on a chart called a audiogram. The audiogram is a graph that show frequency or pitch across the top and intensity or loudness down the left side of the graph.

Once the audiogram is completed the audiologist can tell:

1. Whether both ears have same thresholds or is one ear better than the other ear.
2. The degree of the hearing loss, e.g., moderate, profound.
3. The configuration of the hearing loss, that is, whether the thresholds are similar in all frequencies or better in the low frequencies than in the high frequencies.
4. Whether there is an “air-bone gap” meaning there is a difference in air conduction and bone conduction thresholds. This could mean that middle ear disease exists.

All of these professional decisions and judgments can be made by a licensed audiologist and the test results explained in detail to parents.

Adapted from Infant Hearing Resource, Hearing & Speech Institute, Portland, Oregon.