Indices of Cognitive Processing in Autistic Learners

Event-related Potentials (ERPs) were recorded to both tuditory and visual stimuli from the scalps of nine autistic males and4re normal, ) controls to examine the differences in information processing strategies. ( Subjects were tested on three different tasks (in the following order): 1) an auditory missing stimulus paradigm; 2) a visual color.dischriminition; 'and 3) an auditory tone discrimination task,. The brain electrical activity was recorded and anlyzed (both trial by trial and averaged wavefdrm) for one thousand msecs follow,ing the target stimuli.' Results indicate, that the amplitude of the averaged P300 component was significantly rediced,in the , autistic group compared to the normal group. The N100 component was al4 smaller in amplitude, but it did not reach statistical significance. The latency of components was not significantly different among grOups=during the visual tasks; however, the latency of the P300 compOnent was significantly longer in the autistic group during auditory tasks. The accurac of per, formance with the operant button press and the appearance.of the N100-P200 componkt5 in the autistic, group suggest that the autistic individuals are attentive to the task. .The sporadic occurrence of the P300 (when analyzed trial by trial) indicates that the autistic group is not consistently engaged in active stimulus evaluation at the higher information proCessing level. The delayed latency of the P300 component during auditory tasks in tia the autistic group hints that there is more time required to complete stimulus , I evaluation in the auditory modality at the higher processing level than is required of the visual system at the same level. These results are consistent with the view that autistic learners show higher order procesOng deficits as 4 displayed by-their profound language defects and problems with complex thoughts,'