More clues to understanding why children with autism have trouble responding to speech. As a group high functioning autistic children (age 10-15) showed lower levels of left anterior cingulate activation in response to novel (below) or deviant sounds. This is consistent with now numerous other studies showing brain activation differences in the auditory cortex.
It is important to notice the splay in variations among these subjects, though. It means that as a group more HFA children have trouble detecting auditory changes (this affects how you discriminate words and sounds), but that some children could have normal auditory perception.
This work will be important to translate into practical information for individual kids. Auditory training could be beneficial for some, but completely inappropriate for others.
Auditory Event-Related fMRI in Autism
Abnormal Auditory Cortical Processing in Autism