The Quantification of Variability in Event-Related Potentials and Its Application to Schizophrenia

Schizophrenics are more variable than normals on almost any psychophysiological measure (Callaway 1975). One of these variable measures is the event-related potential (ERP), which is the brain’s transient electrical response to discrete events. Previous investigations of ERP variability in schizophrenia have employed curve fitting techniques, peak picking, or principal component analysis to determine amplitude or latency variability of individual ERP components, particularly the P300 component (Michalewski 1986; Thomas et al. 1989). Such approaches are, however, made difficult by the presence of the ongoing EEC.