Background: Although newborns are presumed to have cognitive ability, studies on the objective cognitive ability of neonates are making little progress.
Methods: We gave auditory and visual stimuli to newborns whose conceptional age ranged from 35 to 43 weeks and recorded the mismatch negativity (MMN) that is said to reflect the process by which stimuli are detected automatically. We compared the waveform and latency of the MMN.
Results: The mismatch negativity waveform in newborns was similar to that of adults. The MMN latency tended to shorten with an advance in conceptional age and was especially shortened between 36 and 37 weeks of fetal life. In some newborns whose clinical course indicated a possibility of their having cognitive dysfunction, the MMN latency was prolonged.
Conclusions: Newborns also have cognitive ability and MMN is useful for objectively evaluating the cognitive ability in newborns.