Phoneme perception in a neonate with a left sylvian infarct.

We report the case of a neonate tested three weeks after a neonatal left sylvian infarct. We studied her perception of speech and non-speech stimuli with high-density event-related potentials. The results show that she was able to discriminate not only a change of timbre in tones but also a vowel change, and even a place of articulation contrast in stop consonants. Moreover, a discrimination response to stop consonants was observed even when syllables were produced by different speakers. Her intact right hemisphere was thus able to extract relevant phonetic information in spite of irrelevant acoustic variation. These results suggest that both hemispheres contribute to phoneme perception during the first months of life and confirm our previous findings concerning bilateral responses in normal infants.