Written by Stephen M. Edelson, Ph.D.
Center for the Study of Autism, Salem, Oregon
Autistic individuals typically have problems processing auditory information. One auditory processing problem occurs when a person hears speech sounds but he/she does not perceive the meaning of the sounds. For example, if someone says the word ‘shoe,’ the person may hear the speech sound, but he/she does not understand the meaning of the sound. Sometimes the lack of speech comprehension is interpreted by others as an unwillingness to comply. However, the person may not be able to retrieve the meaning of the sound at that particular time.
Eric Courchesne of the University of California at San Diego has found significant impairments in auditory processing in autistic individuals using P300 brain wave technology (see Courchesne, 1987 for a review). The P300 brain wave occurs 300 milli-seconds after the presentation of a stimulus. (The ‘P’ refers to the positive polarity of the brain wave.) The P300 is associated with cognitive processing, and this brain wave is considered an indication of long-term memory retrieval (Donchin, Ritter, & McCallum, 1978). Edelson et al. (1999) examined auditory P300 activity prior to and three months following auditory integration training (AIT). Three autistic individuals participated in the experimental AIT group and two autistic individuals participated in a placebo group. Prior to AIT, all five individuals had abnormal auditory P300 activity, indicating an auditory processing problem. Three months following AIT, the results showed dramatic improvement in P300 activity for those who received AIT (i.e., a normalization of P300 activity) and found no change in those who received the placebo.
We do not know the underlying reason for auditory processing problems in autism; however, autopsy research by Drs. Bauman and Kemper have shown that an area in the limbic system, the hippocampus, is neurologically immature in autistic individuals (Bauman & Kemper, 1994). The hippocampus is responsible for sensory input as well as learning and memory. Basically, information is transferred from the senses to the hippocampus, where it is processed and then transferred to areas of the cerebral cortex for long-term storage. Since auditory information is processed in the hippocampus, the information may not be properly transferred to long-term memory in autistic individuals.
Auditory processing problems may also be linked to several autistic characteristics. Autism is sometimes described as a social-communication problem. Processing auditory information is a critical component of social-communication. Other characteristics that may be associated with auditory processing problems include: anxiety or confusion in social situations, inattentiveness, and poor speech comprehension.
Interestingly, those individuals who do not have auditory processing problems are often ‘auditory learners.’ These children do very well using the Applied Behavior Analysis (ABA) approach, whereas those who are visual learners do not do as well with this approach (McEachin, Smith and Lovaas, 1993). Given this, one might suspect that many visual learners have auditory processing problems and that visual learners will do quite well with a visual communication/instruction approach. It is also possible to provide visual support with ABA programs that have an auditory component. In this way, the visual learner can process the auditory information more easily.
The better autistic children understand auditory information, the better they can comprehend their environment, both socially and academically. The better we understand the autistic child, the better we can develop ways to intervene in an effective manner.
References
Bauman, M.L., & Kemper, T.L. (1994). Neuroanatomic observations of the brain in autism. In M.L. Bauman & T.L. Kemper (Eds.), The neurobiology of autism. Baltimore: Johns Hopkins UP.
Courchesne, E. (1987). A neurophysiological view of autism. In E. Schopler & G.B. Mesibov (Eds.), Neurological issues in autism. New York: Plenum Press.
Donchin, E., Ritter, W., & McCallum, W.C. (1978). Cognitive psychophysiology: The endogenous components of the ERP. In E. Callaway, P. Tueting, & S. Koslow (Eds.), Event-related brain potentials in man. New York: Academic Press.
Edelson, S.M., Arin, D., Bauman, M., Lukas, S.E., Rudy, J.H., Sholar, M., & Rimland, B. (1999). Auditory integration training: A double-blind study of behavioral, electrophysiological, and audiometric effects in autistic subjects. Focus on Autism and Other Developmental Disabilities, 14, 73-81.
McEachin, J.J., Smith, T., & Lovaas, O.I. (1993). Long-term outcome for children with autism who received early intensive behavioral treatment. American Journal of Mental Retardation, 97, 359-372