CHR patients and healthy controls showed highly comparable auditory target detection performance during a novelty oddball task, and both groups had robust auditory ERPs that did not differ in morphology, amplitude, or topography. Importantly, the observed ERP/CSD component structure to frequent, target and novel stimuli in both groups directly replicates our previous findings for this paradigm using a combined CSD-PCA approach (Tenke et al., 2010). In close agreement with prior MEG findings for 17 ultra-high-risk subjects performing an auditory oddball task (Koh et al., 2011), CHR patients showed prominent abnormalities of evoked alpha activity to infrequent task-relevant target and task-irrelevant novel stimuli. The parietal alpha suppression, which prominently followed a mid-parietal target P3b in healthy controls, was markedly reduced in CHR patients, particularly over the right hemisphere. The Koh et al. (2011) study found this abnormal alpha modulation in CHR patients to be intermediate between groups of 18 healthy controls and 10 schizophrenia patients, suggesting that impaired alpha ERD may present a possible risk indicator for the development of schizophrenia. The present findings support this notion in that all three
