• autonomic nervous system
• preterm infants
• heart rate variability
• shared reading
• parent-infant dyad
• cardiovascular synchronization
• nonlinear dynamics

Introduction: Preterm birth is associated with an increased risk of short and long-term adverse impact on the autonomic nervous system (ANS) development, with potential effects on socioemotional scores. Parental early intervention, i.e. early shared book reading, might mitigate the effects on the infant’s ANS maturation.
Methods: In the framework of the research project SHER (Shared Emotional Reading), 22 seven-month-old preterm infants were included in a two-months intervention based on either parent-infant shared reading (intervention group) or play (control group), according to a randomized clinical trial design. A group of 15 nine-month-old infants born at term has been recruited as passive control. After the intervention, the cardiovascular signals of each parent and infant were acquired simultaneously during sessions of shared reading and play. Standard and nonlinear analysis has been used to characterise the infant’s autonomic states and the synchronization of parent-infant dynamics, during shared reading and shared playing tasks.
Results: Statistically relevant differences (p<0.05) have been found both in infant’s ANS features and in the dyad synchronization during the reading activity when compared to baseline and shared play. The intervention infants displayed higher HRV irregularity and complexity compared to term and preterm control, while the intervention dyad displayed higher coupling compared to the preterm control group.
Conclusions: The intervention showed promising results regarding the efficacy of shared reading as an early intervention improving ANS maturation and strengthening parent-infant synchrony.