Dynamic touch reduces physiological arousal in preterm infants: A role for c-tactile afferents?

Andrea Manzotti,Francesco Cerritelli,Jorge E Esteves,Gianluca Lista,Erica Lombardi,Simona La Rocca,Alberto Gallace,Francis P Mcglone,Susannah C Walker

doi:10.1016/j.dcn.2019.100703

Abstract

Preterm birth is a significant risk factor for a range of long-term health problems and developmental disabilities. Though touch plays a central role in many perinatal care strategies, the neurobiological basis of these approaches is seldom considered. C-Tactile afferents (CTs) are a class of unmyelinated nerve fibre activated by low force, dynamic touch. Consistent with an interoceptive function, touch specifically targeted to activate CTs activates posterior insular cortex and has been reported to reduce autonomic arousal. The present study compared the effect of 5 min of CT optimal velocity stroking touch to 5 min of static touch on the heart-rate and oxygen saturation levels of preterm infants between 28- & 37-weeks gestational age. CT touch produced a significant decrease in infants’ heart-rates and increase in their blood oxygenation levels, which sustained throughout a 5-min post-touch period. In contrast, there was no significant change in heart-rate or blood oxygenation levels of infants receiving static touch. These findings provide support for the hypothesis that CTs signal the affective quality of nurturing touch, providing a neurobiological substrate for the apparent beneficial effects of neonatal tactile interventions and offering insight for their optimisation.

Highlights

The World Health Organisation estimates that globally 15 million infants are born premature each year
The results of the present study show that a short period of dynamic stroking touch, delivered at a force and velocity to optimally activate C-Tactile afferents (CTs), produces a reduction in the heart-rate of preterm infants that was sustained into a 5-min post-touch period
Dynamic touch was associated with an increase in levels of oxygen saturation, which was not seen in those infants receiving static touch

Summary

Introduction

The World Health Organisation estimates that globally 15 million infants are born premature each year. While in high-income countries, as a result of advances in neonatal care, survival rates are increasing, long term physical and mental health problems as well as developmental disabilities are common (Wong et al, 2016; World Health Organization, 2016). The mechanisms underlying neurodevelopmental delay, reduced neural growth and abnormal neurofunctional organisation associated with preterm birth are currently poorly understood The somatosensory system is the first to develop, from 8 weeks gestational age (GA) (Humphrey, 1964), with fetuses responding strongly to touch to the mother’s abdomen in the third trimester (Marx and Nagy, 2015). It has been hypothesised that activation of sensory nerves in the skin of the foetus by the amniotic fluid during movements is a mechanism underlying

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