| 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.
Author
Stephen M. Edelson, Ph.D.
Center for the Study of Autism, Salem, Oregon
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