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Updated: Aug 6, 2026

A Within-subjects Experimental Protocol to Assess the Effects of Social Input on Infant EEG
Published on: May 3, 2017
Frontal cerebral blood flow change associated with infant-directed speech
1Department of Psychology, Hiroshima University, Kagamiyama 1-1-1, Higashi-Hiroshima, Hiroshima 739-8524, Japan. yuri@sep.email.ne.jp
Objective:
To examine the auditory perception of maternal utterances by neonates using near-infrared spectroscopy (NIRS).
Methods:
Twenty full-term, healthy neonates were included in this study. The neonates were tested in their cribs while they slept in a silent room. First, two probe holders were placed on the left and right sides of the forehead over the eyebrows using double-sided adhesive tape. The neonates were then exposed to auditory stimuli in the form of infant-directed speech (IDS) or adult-directed speech (ADS), sampled from each of the mothers, through an external auditory speaker.
Results:
A 2 (stimulus: IDS and ADS) x 2 (recording site: channel 1 (right side) and channel 2 (left side)) analysis of variance for these relative oxygenated haemoglobin values showed that IDS (Mean = 0.25) increased brain function significantly (F = 3.51) more than ADS (Mean = -0.26).
Conclusions:
IDS significantly increased brain function compared with ADS. These results suggest that the emotional tone of maternal utterances could have a role in activating the brains of neonates to attend to the utterances, even while sleeping.

