In a prior study, we recorded nose-referenced 30-channel ERPs during a visual continuous word recognition paradigm in 24 schizophrenic patients and 19 healthy controls (Kayser et al., 1999). Although patients showed poorer accuracy of word recognition, they had the same ERP old-new effect as controls (i.e., greater late positivity between 400–700 ms at medial and parietal sites) overlapping a late positive complex of comparable amplitude in both groups. Patients did, however, show a striking reduction of earlier negative potentials (N1, N2), and the amplitude of N2 and the N2-P3 complex to words was greater over left than right inferior temporal-parietal sites in controls but not patients. Notably, these ERP measures correlated with performance accuracy in either group, except for the N2-P3 asymmetry in patients, suggesting that the poorer performance of schizophrenic patients in the word recognition memory task stems at least in part from a deficit in a left-lateralized system involved in phonological processing, comparable to that seen in dyslexia (Salmelin et al., 1996).
