Many behavioural theories describe Autism Spectrum Disorder (ASD) as having
roots as a social disorder. However, our research adds to previous studies showing that
those with ASD with normal intelligence have perceptual problems that affect their social
functioning. We report that those with ASD perform worse than controls in all of our
speech tasks that measure the ability to filter speech in noise, specialization for native
speech sound categories, and audio-visual integration of speech sounds. Those with ASD
also performed worse on tasks measuring specialization for native musical meters, but
not on tasks measuring the use of absolute pitch or knowledge of tonal harmony. This
research is important because little is known about some of these areas of auditory
processing. Thus, our battery forms a profile in which to understand speech and musical
processing in ASD. This research also provides some explanation for why perceptual
areas that develop early instead of late are most impaired in ASD, which can have
implications for remediation. Besides perceptual problems, we found in other research
that those with ASD have abnormal prosody, which varies according to language ability.
We report that those with Autism Moderate Language Functioning (A-moderateL) use a
restricted pitch range relative to those with Autism High Language Functioning (AhighL)
and controls, whereas those with A-highL use a larger pitch range relative to those
with A-moderateL and controls.
