The Use of Otoacoustic Emissions

What is Universal Newborn Hearing Screening?

Detecting hearing problems in infants has been determined to be very important for a child to achieve his or her proper learning development. The ability to hear is integral to the development of speech and language. A hearing loss in a young child can affect the child's academic performance, behavior, self-image and ability to interact with others. Three (3) out of every one thousand (1000) babies are born with some type of hearing loss making it the most occurring birth defect. If the hearing problem is discovered at an early age, then appropriate action can be taken to improve the child's hearing condition. Research has shown that the longer a child's hearing loss has gone undetected over the age of six (6) months, the child can never completely regain what he or she has lost from not having the stimulus of hearing the different speech frequencies. For amplification to have its maximum effect, intervention must begin during the preverbal period.

The Impact of Hearing on Learning and Communicating

Our abilities to learn and communicate are based on a complex series of events. This sequence begins with our ears processing information and transmitting it to our brain. The brain then interprets, processes, and finally translates this data into a universe of words, meanings, and understandings. Any interruption in this series of events affects the entire pathway. Thus, a young child's ability to hear is essential for learning and communicating. Any hearing loss in young children affects their speech perception, language acquisition, and academic capabilities along with their self-image, social and emotional development.

New technology incorporated in otoacoustic-emissions testing equipment (or OAE, for short) has recently enabled audiologists to screen infants for possible hearing problems in a way that was not possible just a few short years ago. In our offices we have the requisite equipment to record and analyze both transient OAEs and distortion-product OAEs. Evoked OAE technology stimulates and detects sounds created by a biomechanical process that originates from the outer hair cells within the cochlea as it processes these sounds. If the middle-ear function is normal, these cochlear sounds are measurable by a microphone placed in the external ear canal. While this test cannot say whether the sound made it all the way to the brain via the auditory nerve, it does verify near-normal cochlear function. The presence of OAEs indicates hearing as good as or better than 25 to 30 dB (Hurley & Musiek 1994). Normal hearing is a range from 0 to 20 dB. Failure of an ear to register an OAE indicates that further audiological investigation is needed. If a child does not pass the screen, the child will be closely followed until a definitive answer is found.

Nearly one-half of the states have required that all newborns be screened for potential hearing losses. Presently, there is a bill in the Pennsylvania Legislature to require screening within our state.

OAE testing is also diagnostic in determining the impact of ototoxic drugs, detecting early signs of noise exposure and the site of lesion testing. OAE testing is used to evaluate young children, foreign-speaking persons, confused older adults, physically and mentally challenged patients, or people who may have a functional hearing loss.