Lateralization of speech processing in the brain as indicated by mismatch negativity and dichotic listening

The goal of the present study was to evaluate the differences between dicho tic listening and mismatch negativity as measures of speech lateralization in the human brain. For this purpose, we recorded the magnetic equivalent o f the mismatch negativity, elicited by consonant-vowel syllable change, and tested the same subjects in the dichotic listening procedure. The results showed th:lt both methods indicated left-hemisphere dominance in speech pro cessing. However, the mismatch negativity, as compared to the right-ear adv antage, suggested slightly stronger left-hemisphere dominance in speech pro cessing. No clear correlation was found between the laterality indexes of m ismatch negativity and right-car advantage calculated from dichotic listeni ng results. The possible explanation for this finding would be that these t wo measures reflect different stares of speech processing in the human brai n. (C) 2000 Academic Press.