Auris Repletus by Dr. Tom Goyne

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:

What's an Audiologist?

Ever since my early college days, I've had to explain to people in social situations what an audiologist is.  "You're an ah, ah, audiologist -- did you say?  What's that?"  In the end, it's not that surprising how few people understand what an audiologist is because compared to other professions such as lawyers, physicians, dentists, accountants, etc., audiology is in its infancy.

After World War II, a great deal of veterans were left with hearing loss as a result of their service.  This didn't make WWII unique as there were certainly veterans with hearing loss ever since gunpowder was introduced to the battlefield, however, by the mid-1940's, healthcare had advanced to the point that not just life-threatening conditions or injuries were a concern, but so was quality of life.

The educational requirements to become and audiologist have changed over the years and to this day, the requirements are different from state to state as well as from country to country.  Every state today requires at least a master's degree to be licensed as an audiologist and most require a doctoral degree (Ed.D., Ph.D., D.Sc., and most commonly, an Au.D.).

The training and coursework that goes into obtaining a degree in audiology has also changed over the years and is now quite comprehensive.  Topics range from fundamentals such as the diagnostics of hearing and balance, anatomy, physiology, and acoustics, to the detailed, such as psychoacoustics, intraoperative monitoring, neuropsychology, genetics, forensics, pharmacology, digital processing, and computer instrumentation.

There are few professions like it.  In what other field are you required to wrap your head around a digital processing algorithm one minute and then somewhat forcefully tug on the ear of a very nice grandmotherly person the next?