Touch shapes preterm babies’ brains

A baby’s earliest experiences of touch have lasting effects on the way it responds to touch at home.

Babies born prematurely are less likely to have the usual brain response to gentle touch. However, when given supportive touch while still in the hospital, their brain responses become more like those of full-term babies by the time they go home. Nathalie Maitre and colleagues measured the brain responses of 125 preterm and full-term babies using a soft, high-density EEG net.

We spoke with Maitre about the Current Biology study, which has care implications for the 15 million preterm babies born each year.

ResearchGate: What motivated this study?

Nathalie Maitre: Preterm infants have high rates of delays and neurodevelopmental impairments. We know from research that this can be linked to early problems reacting to sensations in daily life. Infants who have difficulties responding to touch, sound, position changes, and sights also have problems with movement, learning language, and higher cognitive skills. We wanted to study the importance of responses to touch because it is one of the earliest senses to functionally develop in human infants.

However, we did not want to assume that we could tell what babies feel, because most of our guesses would have been based on what older children showed outwardly. Our team wanted to look "inside" the infant brains to see what they actually felt in response to gentle touch. We did not want to assume that other signs, such as facial expressions or vital signs, could tell us how babies’ brains process touch.

This photograph shows measuring preterm baby brain function using high-density EEG. Credit: Nationwide Children's Hospital.

RG: Can you tell us what you found?

Maitre: The earlier a baby is born, the more likely it is to have a smaller brain response to gentle touch when going home from the hospital. The more supportive touch preterm babies experience while still in the hospital, the more their brain responses to touch will be like term-born babies by the time they go home. Conversely, the more preterm babies experience painful procedures, the less their brain responses will be like those of term born babies, even when they receive pain medications and sucrose to try and mitigate pain. ​We were very surprised to find that if babies experience painful procedures early in life, their sense of gentle touch can be affected. Thanks to the groundbreaking work of other scientists who study the responses to pain in the baby brain, we can make sense of our findings as a kind of cross-over in the wiring of the brain between two different kinds of touch sensation. ​

RG: How did you conduct the study?

Maitre: We used a soft, high-density EEG net and repeatedly measured the baby brain’s response to a soft puff of air, comparing it to the brain’s response to a sham puff. Our analysis utilized the latest topographic analysis tools, developed by the team in Switzerland. We did this with term-born babies in the nursery and in preterm babies who were in the neonatal intensive care unit, right before they were going home. ​​

RG: Why do babies, particularly preterm babies, need touch?

Maitre: All babies need supportive touch to build essential connections in their brains. For preterm infants, providing this touch is especially important because they miss months of typical development inside the uterus of the mother, where they receive constant, non-noxious tactile feedback. This tactile feedback is essential, as it happens during a critical period of brain development. In some other sensory systems, when input does not happen during critical windows, the entire sensory system can be permanently affected. We do not know if this is the case for touch, but we certainly can see the impact of deprivation in preterm infants.

Touch is a critical building block of infant learning. It helps infants learn how to move, discover the world around them, and how to communicate. Touch allows them to learn these skills even before their vision is fully developed, and certainly before they learn verbal skills.  ​

RG: How can hospitals best integrate the results of your study into caring for preterm babies?

Maitre: Making sure that preterm babies receive positive, supportive touch, such as skin-to-skin care by parents, is essential to help their brains respond gentle touch in ways similar to those of babies who experienced an entire pregnancy inside their mother’s womb. When parents cannot do this, hospitals may want to consider occupational and physical therapists to provide a carefully planned touch experience, which is sometimes missing from a hospital setting. ​

RG: Does it matter who touches the baby?

Maitre: Our study included touch by therapists and parents, and we only counted touches when skin-to skin contact was involved. This is based on studies of skin-to-skin (kangaroo care), breastfeeding, and massage that have shown promising results in helping the maturation of the nervous system. While we know that certain types of touch appear supportive, we did not have the tools before this to study which forms may prove more beneficial than others. In general, infants benefit more from their parents’ touch for other reasons such as emotional bonding, increased opportunities for parents to practice responsivity, and in the case of breast feeding and skin-to-skin care, increased health benefits for both mom and baby.

Featured image courtesy of Bridget Coila.