Single-trial analysis of the auditory N100 improves separation of normal and schizophrenia subjects

The N100 component of the auditory evoked potential (EP) has been recently used to study sensory gating deficits in schizophrenia subjects compared to normal controls. Previously, we used selective averaging to show phase synchronization differences in brain activity between the two populations. In this study, we employed our recently developed iterative independent component analysis (iICA) procedure to measure single-trial EPs in the context of a double-stimulus paradigm. Using the amplitude and latency of the N100 components of the first and second stimuli responses obtained from iICA and four different classification algorithms we were able to accurately classify subjects with 100% sensitivity and 100% specificity. In contrast, the same amplitude and latency features computed from average EPs provided only 69% classification accuracy, with 63% sensitivity and 75% specificity, respectively. We conclude that inter-trial temporal variability plays a significant role in the well-known sensory gating deficits found in schizophrenia patients.