Beverly A. Wright- b-wright@nwu.edu
Audiology and Hearing Sciences Program
Northwestern University
2299 North Campus Drive
Evanston, Illinois 60208-3550
Hotel during conference: Westin 900-228-3000 (possibly listed
under the name Laurie Heller)
Popular version of paper 2pPP6
Presented Tuesday afternoon, June 23, 1998
ICA/ASA '98, Seattle, WA
One child out of every twelve who is otherwise unimpaired has a learning problem related to speech and language processing. These children, numbering over three and one-half million in the United States, have extreme difficulties either producing and understanding spoken language, or reading, or both. Such language- based learning disorders have a profound negative impact on the academic performance and social interactions of affected children and consequently on their adult lives.
A number of researchers have reported that children with language problems also often have trouble correctly perceiving sounds other than speech, when those sounds are brief and follow one another rapidly. This deficit is interesting because the individual sounds of speech are themselves brief and occur in rapid succession. Thus at least part of the language difficulties experienced by these children may come from their inability to correctly hear the sounds of speech.
Recently, researchers at the University of California San Francisco and the University of Florida reported details of the auditory perceptual problems of children with language difficulties. They tested the ability of children with and without language problems to hear a brief tone that was presented either before, during, or after a somewhat longer noise. The children with language problems clearly had the greatest trouble hearing the tone when it was presented before the noise--the easiest test for children with normal language skills. However, the impaired children had less difficulty hearing the tone when the following noise did not contain the same frequency as the tone. These results suggest that the problems impaired children have with the perception of rapidly presented sounds, such as speech, occur, surprisingly, because one sound is essentially wiped out by another sound of similar frequency that comes after it.
That one sound can seemingly work backward in time to disrupt the perception of what came before it has been known for many years. The new news is that this process may be dramatically exaggerated in many children with language difficulties. Researchers at Northwestern University and the University of California San Francisco are now investigating how practice influences the ability of adult listeners with normal language skills to detect a tone immediately followed by a noise. Their preliminary data indicate that, with training, adults can greatly reduce or even eliminate the interference caused by the noise. It also appears that such training at one sound frequency leads to improvements at other, untrained, sound frequencies. These results suggest that such training may benefit children with language disorders.