Contextual probability evaluation in autistic, receptive developmental language disorder, and control children: event-related brain potential evidence.

Compared 8- to 14-year-old children with either autism or receptive developmental language disorder (RDLD) to age- and IQ-matched normal controls in their ability to detect both frequent (p = .70) and infrequent (p = .30) randomly presented auditory stimuli under task and no-task conditions. Event-related brain potentials (ERPs), behavioral reaction times, and target detection accuracy rates were measured. Although the three groups of children performed in a similar manner on behavioral measures, only the children with autism demonstrated an abnormally small amplitude of the P3b, a component of the ERP. This result is interpreted in terms of (a) the consistency of this finding with other ERP studies involving older individuals with autism; and (b) its significance with respect to the difficulty children with autism have in modifying their expectancies to contextually relevant sequences of auditory information.