The cerebral hemodynamic response to phonetic changes of speech in preterm and term infants: The impact of postmenstrual age.

Takeshi Arimitsu,Atsuko Matsuzaki,Kazushige Ikeda,Mariko O Uchida,Tatsuhiko Yagihashi,Takao Takahashi,Yasuyo Minagawa

doi:10.1016/j.nicl.2018.05.005

Abstract

Higher brain dysfunction, such as language delay, is a major concern among preterm infants. Cerebral substrates of cognitive development in preterm infants remain elusive, partly because of limited methods. The present study focuses on hemodynamic response patterns for brain function by using near-infrared spectroscopy. Specifically, the study investigates gestational differences in the hemodynamic response pattern evoked in response to phonetic changes of speech and cerebral hemispheric specialization of the auditory area in preterm infants (n = 60) and term infants (n = 20). Eighty neonates born between 26 and 41 weeks of gestational age (GA) were tested from 33 to 41 weeks of postmenstrual age (PMA). We analyzed the hemodynamic response pattern to phonemic and prosodic contrasts for multiple channels on temporal regions and the laterality index of the auditory area. Preterm infants younger than 39 weeks of PMA showed significantly atypical hemodynamic patterns, with an inverted response shape. Partial correlation analysis of the typicality score of hemodynamic response revealed a significant positive correlation with PMA. The laterality index of preterm infants from 39 weeks of PMA demonstrated a tendency rightward dominance for prosodic changes similar to term infants. We provide new evidence that alterations in hemodynamic regulation and the functional system for phonemic and prosodic processing in preterm infants catch up by their projected due dates.

Highlights

Major disabilities in preterm infants are becoming less frequent as medical technologies advance
Even if preterm infants do not present with major central nervous system disorders or other significant complications at discharge from hospital, higher brain dysfunctions may appear during development (Luu et al, 2009; Aarnoudse-Moens et al, 2009)
We focused on postmenstrual age (PMA), taking gestational age (GA), post-natal age (PNA), and birth weight into consideration, because hemodynamic response function (HRF) is closely related to the physiological development of neonates' vascular systems, which may continuously develop before and after birth

Summary

Introduction

Major disabilities in preterm infants are becoming less frequent as medical technologies advance. Even if preterm infants do not present with major central nervous system disorders or other significant complications (e.g., grade 2 to 4 intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia, BPD or necrotizing enterocolitis, NEC) at discharge from hospital, higher brain dysfunctions may appear during development (Luu et al, 2009; Aarnoudse-Moens et al, 2009). Such dysfunctions in the cognitive system can be examined by neuroimaging of the brain function and brain anatomy of infants. Studying these processes in preterm infants will provide insights into early developmental milestones and the relationship between brain maturity and function

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