Early and late mismatch negativity elicited by words and speech-like stimuli in children

In auditory perception the bl ain's attentional and preattentional mechanis ms select certain stimuli for preferential processing and filter out irrele vant input. This study investigated nonattentive auditory processing in chi ldren. Event-related potentials (ERPs) provide a means to study neural corr elates related to language and speech-sound processing. Mismatch negativity (MMN) is an ERP wave that indicates attention-independent perceptual chang e detection. In this study cortical ERPs were elicited by complex tones, na turally spoken words, and pseudowords, with each stimulus type containing e qual acoustical elements. Tones elicited a bifurcated mismatch negativity ( MMN), with early MMN (peaking at 150-200 ms) being more dominant. On the ot her hand, words elicited a strong late MMN, peaking at about 100-450 ms aft er stimulus onset. The MMN wave form was significantly weaker for pseudowor ds than for words. The late MMN wave, especially for word differences, was found to reflect summating MMN generators and memory trace formation on ges talt bases. Results suggest that the auditory processing, even nonattended, is highly associated with the cognitive meaning of the stimuli. (C) 2001 A cademic Press.