My four-year-old daughter recently was given a hearing screening at the local health department. She was taken by her preschool and I wasn't present at the time. I just recently got the test results. She was given what looks like four different tests: pure-tone audiometry, otoscopic, impedance and a frequencies test. She failed all of them, and they recommend a followup. Could you please explain what these tests are and give me a recommendation about where to go from here?

L.H.

Pure-tone audiometry measures your daughter's ability to hear "pure tones" (think of these as musical notes). The tester plays a tone at a particular pitch and volume, and your daughter tells the tester whether she can hear it or not. The volume is decreased until, eventually, your daughter can no longer hear the tone. The volume at which she can hear the tone about half of the time is called the "threshold." The test is typically repeated at different pitches, and if the tester used headphones or earphones, he or she would have tested each ear individually. The test thus provides information regarding each ear's ability to hear different pitches of sound.

Otoscopic examination means that the tester looked into your daughter's ears with an instrument called an otoscope. You have probably seen your daughter's pediatrician do this many times. The otoscope illuminates and magnifies the eardrum. The tester is inspecting the eardrum to see if it looks normal. An experienced examiner can detect fluid behind the eardrum, scarring of the eardrum, a hole in the eardrum and so forth.

Impedance measures the eardrum's ability to absorb sound energy. One common way to "fail" this test is if the child has a hole in the eardrum. An even more common way to "fail" it is if she has fluid behind her eardrum (the space behind the eardrum is normally full of air, not fluid). Scarring of the eardrum and/or damage to the middle-ear bones (usually due to trauma or infection) are other problems that we see on occasion.

I am not sure what is meant by a "frequencies" test. Frequency is essentially the same as pitch, so to me a frequencies test would be the same as pure-tone audiometry.

One thing is definitely true: The facilities available for testing hearing at the local health department are usually inferior to the facilities maintained by an audiologist. An audiologist is a professional who specializes in the testing of hearing. Audiologists also function as hearing-aid providers, but not all hearing-aid providers are audiologists. Most audiologists are very skilled in testing children. There are techniques available for testing hearing even in infancy.

Your daughter will almost certainly need to be evaluated by an audiologist and an ear, nose and throat specialist (ENT). My recommendation would be for you to bring the test results to your daughter's pediatrician, and ask him or her who to see for your daughter's further care. Many ENTs work closely with a particular audiologist, often within the same office. Thus, it may be possible for you to have your daughter re-tested by an audiologist and be seen by an ENT during the same office visit. These specialists can provide you with information regarding the magnitude of your daughter's hearing problem and the treatment options that are available to her.