Remember those tiny hair cells in the cochlea? There are actually two sets. The inner hair cells respond to sound, sending nerve impulses to the brain. The outer hair cells move in response to sounds and actually make a sound of their own. With a special microphone and computer we can accurately measure these sounds, or emissions, coming from your baby's ears as soon as a few hours after birth. Many hospitals are now screening all babies for hearing loss using OAE's.  If your baby doesn't have measurable OAE's it may mean several things.

It may mean there is too much noise in the nursery to test effectively. Another possibility is there may be some fluid in the ear canals left over from the birth process. The third possibility is that the cochlea is not responding well, indicating a hearing loss. While OAE's are a reliable way to screen for a working cochlea, they have some important limitations. OAE's can only be found if the hearing loss is less than 30 to 40 dB. They are also susceptible to human error. Because of these issues, children who do not pass their first OAE screening are usually re-screened in a more controlled environment. If the OAE's are absent or reduced a second time, the child should be referred for an Auditory Brainstem Response test, or ABR.

  The images below show two types of OAE test results.  On the left are Distortion Product Otoacoustic Emissions (DPOAE) and on the right are Transient Evoked Otoacoustic Emissions (TEOAE).  In both cases, the upper image is a normal or "pass" result and the lower images are abnormal or "refer" results.

Normal DPOAE Results

Normal TEOAE Results

Abnormal DPOAE Results Abnormal TEOAE Results