Management & Diagnosis
Recommendations for management of AN/AD
One of the leading authorities on AN/AD is Charles Berlin Ph.D., who is Professor of Hearing Science and Clinical Professor of Otolaryngology Head and Neck Surgery, LSU Health Services Center and also retired Director of the Kresge Hearing Research Laboratory, New Orleans. He has managed over 300 cases of the disorder.
His data has shown that Auditory Verbal Therapy (AVT) prior to a cochlear implant has been the LEAST successful way to manage AN/AD, while AVT AFTER the implant is an excellent choice.
Since we saw our first patient 20 years ago (and did not know what we were seeing) and because we have tried hearing aids on many of them (all unsuccessfully as a tool for learning language) we no longer recommend aids or try to correct the audiogram.
Professor Berlin makes the following recommendations for the early months:
If a child is newborn and has a history of prematurity or hyperbilrubinemia (neonatal jaundice) we recommend watchful waiting and regular assessment of normal auditory orienting, babbling and language comprehension. During this watchful waiting period we urge parents to learn to use Cued Speech (CS) as a way to supplement lip reading and teaching the phonology of the home language.
How the diagnosis is made
Typically children, and now, with early diagnosis, babies, are tested with the following:
- Otoacoustic Emissions (OAEs) tests whether the outer hair cells of the ears function normally. The OAE test uses small earphones to present clicks or a series of paired tones to the ear. A microphone then measures an echo response from the inner ear and this estimates how the outer hair cells respond to sound.
- Auditory Brainstem Response (ABR) uses electrodes placed on the head. Like the OAE test, sounds are presented to the ear through small earphones, but in this test the electrodes pick up responses which indicate how the hearing nerve and parts of the brain are responding to sound.
With auditory neuropathy ABR responses are absent or abnormal but the OAEs are (or once were) normal. Early diagnosis is important because over time, or after hearing aid use, the OAEs often disappear and the patients become indistinguishable from those patients with less complicated forms of deafness.
Note: There are other indicators (for example Middle Ear Muscle reflexes which are absent or seriously elevated) which are outside the scope of this research.
Dr Berlin writes:
Children and adults with AN/AD can be very confusing. Because their audiograms either fluctuate markedly or range from total deafness to almost normal sensitivity, audiologists and otolaryngologists may mismanage them for long periods of time. This mismanagement may take the form of constant reliance on hearing aids and strict Auditory Verbal Therapy with no visual cues or diagnosing them as "normal" because they have normal otoacoustic emissions or mis-diagnosing them as having "Central Auditory Processing Disorders". Their hearing abilities lie along a continuum from virtually normal in clinical hearing performance in a sound booth (except when noise is added, in which case hearing is universally very poor) to total deafness, but they always have absent or grossly abnormal Brainstem Responses and elevated or absent middle ear muscle reflexes.