AUDITORY EVENT-RELATED BRAIN POTENTIALS IN AUTISTIC-CHILDREN AND 3 DIFFERENT CONTROL-GROUPS

ERPs to auditory stimuli, generated during an oddball task, were obtai ned in a group of autistic children and three control groups (normal, ADDH, and dyslectic children, respectively). The task included the pre sentation of standards, deviants, and novels and had a (between-group) passive vs. active (counting) condition. It was examined whether 1) i t was possible to replicate several earlier findings, 2) autistics man ifest an abnormal lateralization pattern of ERPs, 3) autistics have an abnormal mismatch negativity (MMN), and 4) differences between autist ics and normals are really specific to the autistic group, The only fi nding that could be replicated was that autistics have a smaller A/Pcz /300. There was no evidence for abnormal lateralization or abnormal MM N; however, there was an unexpected effect of the task manipulation on the amplitude of the P3: in autistics, the occipital P3 to deviant st imuli was significantly larger in the active than in the passive condi tion, a finding, like the replication of the smaller A/Pcz/300, specif ic to the autistic group, It was suggested that the auditory occipital task effect is related to understimulation of the occipital lobe by v isual stimuli in autistic children.