Objectives: To examine attentional processing in patients with ASD, patients with schizophrenia and a control group, event-related potentials (ERPs) were recorded in an oddball paradigm. Previously, infrequent stimuli in this paradigm elicit a large positivity (P300). P300 has been proposed as the neural signature of the working memory update of changes in the environment (Donchin & Coles, 1988). Specifically, variations in P300 latency and amplitude have been taken to reflect differences in the degree and quality of attentional mechanisms required to change the mental model of the environment.
Methods: 10 patients with ASD, 10 patients with schizophrenia, and 10 healthy controls were exposed to a visual oddball task (frequent stimulus: large circle; odd stimulus: small circle). All participants were asked to silently count the odd stimuli while ERPs were recorded.
Results: For healthy controls a standard P300 oddball effect was observed. The P300 oddball effect for patients with ASD and schizophrenia was qualitatively different in terms of amplitude, latency or scalp distribution.
Conclusions: P300 results are disussed in terms of structural and functional brain abnormalities associated with ASD and schizophrenia. The present ERP results contribute to the ongoing debate about whether ASD and schizophrenia share a common pathogenesis.