Development of auditory evoked fields in human fetuses and newborns: A longitudinal MEG study

Objective: To investigate the maturation of the auditory cortex by non-invasive recording of auditory evoked magnetic fields in human fetuses and newborns with the relatively novel and completely non-invasive technology of MEG. Methods: Serial recordings were performed every 2 weeks on 18 fetuses beginning from week 27 of gestational age until term with a follow-up recording on the newborn. Auditory stimulation consisted of tone bursts in an oddball design with standard tones and deviant tones. Results: In 52 of 63 fetal and in all of the neonatal recordings an auditory evoked magnetic field was obtained. A decrease in latency with increasing age of the subjects was observed in the combined analysis of fetuses and neonates. Conclusions: With advanced study using MEG, 83% of the measurements showed auditory evoked fields in fetuses that correspond with existing literature in electrophysiology in the past. These findings indicate that MEG is a technique that can be used to investigate maturation of the auditory cortex based on auditory evoked fields in fetuses and neonates. Significance: Maturational changes have been examined in the past. With the use of this novel technique, applied to a serial study, it is possible to trace the development of auditory responses in utero and newborns. (c) 2005 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.