Background: Event-related potentials (ERPs) are currently utilized to study information processing under the influence of neuropsychiatric disorders and are candidate endophenotypes of schizophrenia. However, the traditional ERP approach discards most oscillatory information in the EEG through grand averaging process. This study tried to focus on ERP component of mismatch negativity (MMN) between control and schizophrenia groups in Taiwan. In addition to traditional (grand average) ERP approach, we also compared the time-frequency analysis results of the mismatch negativity. Methods: MMN values were recorded in 55 schizophrenia patients and 42 controls using an auditory oddball paradigm for the duration of the MMN. Besides the traditional grand average approach, the continuous data files were also used for time-frequency analysis via ERP wavelab. Six parameters were explored: event-related spectral perturbation, WTav, avWT, induced activity, intertrial phase coherence and intertrial linear coherence. Results: Traditional ERP approach discovered that group difference occurred in MMN mean amplitude which was compatible with the previous literature. In time-frequency analysis, schizophrenia subjects have lower intertrial phase coherence than controls. Conclusion: Deficit in preattentive sensory information processing, such as MMN, is prominent in Taiwanese schizophrenia subjects. It may also play a role in the basic integrated neural network activity, which could be further explored by time-frequency approach.
Effect of Parametric Variation of Center Frequency and Bandwidth of Morlet Wavelet Transform on Time-Frequency Analysis of Event-Related Potentials