Hearing screens in infants
My wife and I recently adopted a 1 month old baby boy. He has been with us for 5 weeks now, and we recently noticed that he doesn't seem to respond or startle with loud noises. We have extensive medical background on both the birthmother and father.
Although no prenatal care was given, the baby seemed very healthy and bright eyed. The recent notice of a hearing problem is very disconcerting. We brought the concern up a couple days ago during a routine checkup for our 4 yr old. The babies ears were checked, and there was some pinkness in one ear. Antibiotics were prescribed for the babies ear infection. The doctor was "concerned" about the apparent lack of hearing when he clapped his hands behind the babies head (with no awakening). A follow-up visit is scheduled to see what the antibiotics do for the ears. We've also scheduled with an audiologist to follow.
We are very scared, of course thinking the worst. Are we over reacting! Are there a lot of things that account for the apparent lack of reaction to audible stimuli? Following the audiologist what would be the next step?Question:
About 1 every 1000 babies born in the United States has severe hearing loss in both ears. An additional 5 per 1000 are born with moderate hearing loss. Most of the time, these children are not diagnosed as having this hearing loss until they are almost 3 years old. And even mild early childhood hearing loss effects speech and language development as well as social development. Because of these facts, there are many that believe that all children should be screened at birth for possible hearing loss. In fact, in 1993, the National Institutes of Health came out with the recommendation that all babies have a hearing screen before the age of 3 months. Then in 1994, a joint committee made up of members from the American Speech-Language Association, American Academy of Otolaryngology, American Academy of Audiology, American Academy of Pediatrics, and the Directors of Speech and Hearing Programs in State Health and Welfare Agencies also endorsed universal screening of newborns for hearing loss.
So, why aren't all babies being tested for hearing loss? Essentially everyone agrees that screening all infants is a good idea. The trick is to establish an accurate, easy-to-do, inexpensive, non-invasive, and widely available test. Many argue there currently is no such test. Shortly after these recommendations were put forth, a number of prominent experts in the field of hearing pointed out particular flaws with these recommendations:
- The easiest test for screening the large number of newborns has a high false positive rate. It was felt that as many as 20% of infants may have a screen suggestive of hearing loss when there is none.
- To read any test accurately, you have to know what test values are normal and abnormal. Currently, the normal values are based largely on adults. Babies may have different cutoffs as to what is normal.
- What about availability of audiologists trained to read all these hearing screens? In towns with no audiologist, how can babies be assured an accurate hearing screen?
So, what is done now instead of testing all infants? Most physicians go by a set of guidelines which try to identify babies that are at risk for hearing loss, and then test only those babies. Babies at risk include those:
- With a family history of hereditary childhood hearing loss.
- Who have abnormalities of the head.
- Born with certain infections that were contracted while in the womb.
- Who have had meningitis.
- Born weighing under about 3 1/3 pounds (1.5 kilograms).
- Who have had to be on a ventilator after birth for five days or more.
- Who have had jaundice severe enough to require a transfusion.
- Who have had certain medications which are known to have hearing loss as a possible side effect.
- Whose parents or caregivers have concerns about hearing loss, or any type of development delay including speech and language.
Pat, first of all, congratulations on your relatively new addition to the family. Adopting a baby can be quite stressful enough without worrying about possible hearing problems, so I can can certainly understand your concern. Even though babies go to the physician pretty often for routine visits and examinations, the fact is, it is usually the parents who pick up on the hearing loss first. So, you are certainly not over-reacting. I completely agree with your pediatrician about being concerned. However, it is your concern as parents that I find more significant than what is seen in the doctor's office. Babies will often seem to ignore startling noises if they happen to be engaged in a particular activity they find more interesting. However, this generally occurs on a case-by-case basis with the infant having periods of being startled by noises when in a different setting. You are painting a picture of this ignoring noises being the pattern rather than the exception, so referral to the audiologist is definitely a good call.
There are two tests usually used for screening, the Evoked Otoacoustic Emissions (EOAE) test and the Automated Auditory Brain Response (Automated ABR) test. However, these are generally used for screening rather than definitive diagnosis. Therefore, Pat, I suspect your baby's audiologist will use the most sensitive test called the Auditory Brain Stem Audiometry test. This is a non-invasive test in which electrodes (which look like circular bandages with wires coming out) are attached to the head. Then, sound pulses are given in each ear. This causes brain waves which are detected by the electrodes and recorded on paper which is subsequently analyzed. It takes about an hour to do and your baby will probably need to be sedated for the test. The next step will depend entirely on the results of the test and the suggestions of your pediatrician.
I realize waiting for these results will be an anxious time for you and your wife. Take care of one another and keep the communication lines open between the two of you because this stress may sometimes be overwhelming.
Good luck to you.Answer: