Mismatch negativity in socially withdrawn children.

BACKGROUND Individual differences in auditory processing have been associated with social withdrawal, introversion, and other forms of dysfunction in social engagement. The goal of this study was to investigate the characteristics of an electrophysiologic response that is seen to index early cortical auditory processing (mismatch negativity, MMN) among socially withdrawn and more sociable control children. METHODS Auditory event-related potentials to standard and deviant tone stimuli were computed for 23 socially withdrawn children and 22 control subjects. We calculated MMN difference waveforms for frontal, central, and parietal electrode sites. RESULTS Socially withdrawn children had smaller MMN amplitude and longer MMN latencies compared with more sociable control children. CONCLUSION The findings point to the involvement of individual differences in early cortical auditory processing in childhood social withdrawal. Reduced MMN amplitude and delayed latency may index a component of social withdrawal seen in socially withdrawn children and in depressed and schizophrenic patients. The existence of a secondary MMN generator in the frontal cortex may provide a link between the hypothesized frontal lobe involvement in childhood social withdrawal, schizophrenia, and depression and the MMN reductions seen in these conditions.