Gender differences in hemispheric asymmetry of syllable processing: left-lateralized magnetic N100 varies with syllable categorization in females.

The present study used magnetic source imaging to examine gender differences in the functional hemispheric asymmetry of auditory processing. The auditory evoked N100m was examined in male and female subjects in response to natural syllables with varying consonant and vowel as well as nonspeech noise. In an additional task subjects had to categorize different syllables from the first 35 ms of syllables, that is, the plosive and the formant transition. Syllable-evoked N100m activity was larger in the left than in the right hemisphere in female but not in male subjects. This gender-specific hemispheric asymmetry was speech specific, that is, absent when processing meaningless noise. Only in females did the degree of left-lateralization predict successful syllable categorization from short syllable bursts: Results suggest gender-specific differences in spectro-temporal analysis of speech.