MATERNAL SPEECH AS A REGULATOR OF NEURAL DEVELOPMENT IN PREMATURE INFANTS

Abstract

Due to the natural progression of sensory development within the womb, infants born before their 37th gestational week experience developmental delays that leave them vulnerable to adverse health outcomes. Maternal speech has been shown to benefit premature infants by improving outcomes such as weight gain and fewer episodes of feeding intolerance. To our knowledge, limited studies have addressed the benefits of exposure to maternal speech on neural development in premature infants.The objective of this study was to investigate the effect of controlled exposure to a recording of the mother speaking a passage of speech on the neural response obtained using a spectral analysis of heart rate variability in low-birth-weight premature infants tracked from 28 to 34 weeks gestational age. A secondary data analysis was used to address the study objective in 49 premature infants and their mothers. Infants received controlled exposure to maternal recordings of their mothers reciting a rhyme twice daily and were tracked from 28 to 34 weeks of age. With each test session, data collection was conducted 45 seconds before, during, and after a recording of a female stranger reciting the familiarized rhyme was played back to each infant. Infants were randomly assigned to group 1 (controlled exposure to twice daily maternal recording from 28 to 34 weeks), and group 2 (controlled exposure to twice daily maternal recording from 32 to 3412 weeks). High-frequency power was quantified weekly using a spectral analysis of heart periods taken at 45 seconds before, during, and after playback of a stimulus from the electrocardiogram. An exploratory analysis revealed that there was no change in the high-frequency power across weekly test sessions based on group and gender. With increasing age, the high-frequency power for females increased from 32 weeks to 34 weeks before, during, and after playback. A Generalized Linear Mixed Model revealed no significant two-way interaction in the log highfrequency power between groups, genders, sessions, and conditions. It was found that there were no significant differences between groups, genders, and sessions. Significant differences, however, were noted between conditions (before versus during period, estimate=0.22; p=0.006). Further research is therefore needed to further evaluate whether playback of maternal recordings to premature infants is warranted.