Newborn Hearing Screenings

Several times a week, a mother will bring her toddler into my office for a hearing test.  Typically, the mother, nor I, are expecting to find a hearing loss.  By the same token, extraneous circumstances such as a slight delay in speech development dictate that we make sure.

While gathering a case history, the parents will invariably mention to me that, "He/She passed her hearing screening at birth, but we always wondered, how can they tell?  It's not as if he/she was able to respond at just a few days old!"

It's true, other than a startle reflex to very loud sounds, newborns can't respond to sound in a way that we can detect.  But through the application of signal averaging, we can use objective, non-invasive physiologic measures such as otoacoustic emissions (OAE) and auditory evoked potentials (AEP) to determine with relative certainty whether a newborn -- or any other patient incapable of voluntarily responding to stimuli -- has normal hearing or not.

In the case of OAE's sounds are presented to the newborn's ear and if the cochlea is normal sounds will resonate back out.  We record these resonances and if they are a pitch and intensity (right around 0 dB) we expect, we assume normal hearing is present.

AEP's are used more often for newborn screenings because OAE's require the testing to be performed in a quiet setting, and if you have ever been in a hospital's newborn nursery, you know it is not a quiet place.  AEP's on the other hand can be recorded with a fair amount of ambient noise present.  Headphones and sensors are placed on the newborn and electrical signals are painlessly recorded through the newborn's skin [see below].

While these tests are not meant to be a substitute for a comprehensive audiologic examination, performed in a sound-proof booth with a responsive patient, they are reliable and are very good at identifying patients with greater than a mild hearing loss.

Below is a list of states that require newborn hearing screenings, according to the Centers for Disease Control:

Arkansas   California   Colorado   Connecticut   Florida   Georgia   Hawaii   Illinois   Indiana   Iowa   Kansas   Kentucky   Louisiana	Maine   Maryland*   Massachusetts   Mississippi   Missouri   Montana   Nebraska   Nevada   New Hampshire   New Jersey   New York   North Carolina   Ohio	Oklahoma   Oregon   Pennsylvania   Rhode Island   South Carolina   Texas   Utah   Virginia   West Virginia   Wisconsin   Wyoming                                   District of Columbia