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|Thu, 08-17-2006 - 9:04am|
Management of Children with Auditory Dys-synchrony
Barbara Cone-Wesson, Ph.D.
What would be the educational/management advantage of diagnosing a child with auditory dys-synchrony? How would the diagnosis change management/educational strategies, especially in mild cases? In cases of present OAEs and abnormal MEMRs, what additional information would an ABR provide to the educational management program? Is it necessary (or cost effective) to make a referral for an ABR in such cases?
What would be the educational/management advantage of diagnosing a child with auditory dys-synchrony?
If a child has auditory neuropathy/dys-synchrony type hearing loss (AN/D-HL), they may have significant difficulties perceiving speech in noise. Thus, they will be disadvantaged in most classroom situations unless there is a management/treatment plan to address this hearing disability. Audiological management may include provision of amplification or an FM system, as well as counseling the student, teacher and parents about the nature of the hearing disabilities experienced by those with AN/D-HL. The child should also be eligible for whatever accommodations/services are provided for children with other types of hearing losses, whether they be sensory, neural, conductive or mixed. The parents should be counseled about the availability of services for children with hearing loss. Documenting the type and degree of hearing loss is necessary to qualify children for services through the school system. In the child with AN/D-HL it will likely be necessary to determine the degree of hearing loss based upon speech perception tests given in quiet and in noise. This is because the pure tone thresholds in those with auditory neuropathy/dys-synchrony cannot be used to predict the speech perception disability. Some children with only mild or moderate sensitivity losses have speech perception abilities more like those of a child with a profound hearing loss.
How would the diagnosis change management/educational strategies, especially in mild cases?
I am not sure what is meant by "mild". Again, the speech perception abilities cannot be predicted on the basis of the pure tone sensitivity, so it would be necessary to document the child's speech perception abilities in quiet and in noise. If the child demonstrated no difficulties hearing and understanding speech in noise, and school performance did not seem to be impacted by this hearing condition, then, there is no need for intervention. Because some people with auditory neuropathy/dys-synchrony experience progressive hearing loss, annual hearing tests are recommended.
In cases of present OAEs and abnormal MEMRs, what additional information would an ABR provide to the educational management program? Is it necessary (or cost effective) to make a referral for an ABR in such cases?
Just as we would not assume a conductive loss on the basis of abnormal AC thresholds and a flat tympanogram, I think we should be cautious about assuming that there is auditory neuropathy/dsynchrony on the basis of OAEs and abnormal MEMRs. The classic diagnostic signature of AN/D-HL is the presence of evoked OAEs or a cochlear microphonic, and the absence or gross abnormality of short-latency neural responses (compound 8th nerve action potential and auditory brainstem responses). An ABR test is necessary to state definitively that the audiological findings fit the accepted diagnostic criteria for AN/D-HL.
Armed with the definitive diagnostic data, and a thorough assessment of the child's speech perception abilities (in quiet, in noise and, perhaps, in naturalistic settings), the audiologist is in a position to advocate for and obtain the best services for this child's hearing needs.
Dr. Barbara Cone-Wesson has been an audiologist for 30 years. She is associate professor of Speech, Language and Hearing Sciences at the University of Arizona. Her research is in the area of auditory system development and the use of electrophysiologic methods to document normal and abnormal hearing function in infants and young children.