Maturation of mismatch negativity in infants.

The mismatch negativity (MMN) is a pre-attentive change-specific component of the event-related brain potentials (ERPs). During the last decade this response has been intensively studied in adults, but investigations in children and especially in infants are still rare. Recent studies, however, have shown that MMN is also elicited in infants in response to changes in pure tones as well as in phonemes. The present study compared MMN in pre-term infants (conceptional age at the time of recording, 30-35 weeks), full-term newborns and full-term 3-month-old infants. Stimuli were Klatt-synthesized Finnish vowels /y/ and /i/. Previous studies have reported larger MMN amplitudes in school-age children compared with those obtained in adults. According to the results, however, the infant MMN amplitude seems to resemble that of adults. No significant differences in MMN amplitudes were found between the three age groups either. The mean MMN latency, however, decreased significantly with age, although in 3-month-old infants it was not much longer than in a previous study conducted in adults with the same stimuli.