York prof wins early career award for pain research with babies

Not so long ago, many in the medical profession thought infants didn’t feel pain, and whether it was a heel prick or open heart surgery, pain relief was not required. York psychology Professor Rebecca Pillai Riddell (BA Spec. Hons. ’96), had a different take – that infants did experience pain and it was important to figure out just how much and how to manage it.

Infant pain is a largely unstudied area, but Pillai Riddell says there is much to learn, particularly about chronic pain in infancy, which is persistent and prolonged. As a result of her research, Pillai Riddell recently won the Canadian Pain Society’s 2009 Early Career Award in honour of her understanding of neonatal and infant pain and the role of psychosocial factors. The award will be handed out at the society’s annual conference dinner on Friday, May 29 in Quebec City, with Pillai Riddell giving a keynote address at the conference the following day.

“Right now we don’t have a conceptualization for chronic pain in infancy, so acute pain is better understood. What we don’t know or what we’re not prepared for yet is infants who are experiencing pain over the long-term in hospitals,” says Pillai Riddell. “We now know that prolonged exposure to acute and short pain experiences, like needle pokes may make infants more sensitized to pain or less sensitive to pain, there’s the two extremes. What we don’t know is how best to treat it.”

Right: Rebecca Pillai Riddell

Pillai Riddell runs York’s Opportunities to Understand Childhood Hurt Laboratory (OUCH Lab) and is an associate scientist in The Hospital for Sick Children’s Department of Psychiatry Research. She has two research programs on the go, both looking at pain in infancy.

Her first, Understanding Chronic Pain in Infancy, is designed to define what chronic pain is in infancy, to establish a baseline that everyone can agree on, because right now there isn’t one, and to develop a measure to assess it. Chronic pain goes beyond acute pain, which is more temporary in nature – heel pricks, regular needles or post-operative – and can have implications on a person’s life into adulthood.

In collaboration with researchers at York, the University of Toronto, The Hospital for Sick Children as well as Sunnybrook Health Sciences Centre and the Women’s College Hospital, and armed with a Canadian Institutes of Health Research (CIHR) operating grant, Pillai Riddell is looking at infants in the neonatal intensive care units of hospitals. This is where many premature infants experience ongoing pain as medical procedures are performed. “With that comes an enormous amount of iatrogenically induced pain or pain that is a result of the life-saving treatments.”

The goal is to better understand chronic pain in infants by talking with parents, health professionals and national and international experts, which can then be used to develop a conceptual model of chronic pain in infants, followed by a reliable and valid assessment measure, and finally strategies for infant chronic pain management.

Once a baseline is established, the next step will involve assessing how to treat and manage infants in pain. “Right now, we’re in the first stage,” Pillai Riddell says.

For her second line of research, Factors Influencing Maternal Sensitivity to Infant Pain, Pillai Riddell received a CIHR New Investigator Award to look at how the caregiver shapes and impacts infant pain expression. The CIHR award covers her research from 2007 to 2012.

Pillai Riddell and her team are following parents and infants up to one year of age – observing the interaction between the parent and baby at each of the four scheduled immunization times, at two, four, six and 12 months of age.

“We want to see parental behaviours in the immunization settings and we’re really interested in watching them over a long time so we can see how infant pain expression in a normal population develops,” she says. “In addition to that, we’re interested in how parental soothing behaviours affect an infant’s pain reactivity trajectory or pattern of behaviours over time. Some babies are going to get more expressive in their pain, some will stay the same and others will have less expression of pain.”

Her lab is set up in three locations in Toronto and staffed with some 17 people. Already, she is following 150 to 200 infants and that number is growing.

“The exciting thing is that this type of longitudinal pain cohort exists nowhere else in the world. It’s desperately needed, this normal data,” Pillai Riddell says. It examines the importance of the caregiver. “Unlike any other stage in development, the infant is completely reliant on the caregiver to assess their pain and manage that pain. There’s such a symbiotic relationship between the primary caregiver and child. There is literature that says the relationships during the first year impact mental health and physical health throughout the life span.”

What Pillai Riddell wants to know is what parents do to soothe their infant when they get a needle. Soothing behaviours include things like rocking, holding, cooing and patting. She is also exploring caregiver sensitivity – how the parent adjusts their behaviour to the infant. So if rocking their baby isn’t working, do they try a different soothing behaviour? Do they change their baby’s position or perhaps sing to them until they find the thing that works?

Generally the research right now shows that rocking seems to reduce pain reactivity, but Pillai Riddell says she believes it’s important for parents to pay attention to their infant’s cues. “Rocking may be soothing to some babies and absolutely not be soothing for others.” So a mother or father who knows their infant would try a different soothing behaviour quicker; they would change what they do to fit the infant’s needs.

Watching the interaction between caregivers and their infants during immunizations provides what Pillai Riddell calls a naturalistic setting which will tap into how the mother or father consoles their infant in other naturalistic settings outside the lab. “I’m using it as a paradigm to what I think is going to go on when the child bumps his knee, bumps his head, everyday bumps and bruises. So it’s not just how they react in this particular pain context,” says Pillai Riddell. And because she gets to see four different samples for each caregiver and infant, she will also be able to determine if the mother or father improves at soothing their infant over time.

In addition, Pillai Riddell is hoping to put together some quick indicators and strategies, based on attachment styles and how infants express their distress, that can be taught to physicians and nurses so they can help parents soothe their children. Each baby has a predisposition that guides how they react to pain. It’s then up to the caregiver to respond in an appropriately soothing way. “It’s always that interaction. My research is about interactions.”

In the next 10 to 15 years, Pillai Riddell expects her two lines of research to overlap. “I want to build up normal data on infant pain then be able to understand the infant caregiver relationship in neonatal intensive care units of hospitals, where I think it’s going to be even more important because the first year of life is so integral to building that relationship,” she says. “That relationship is so integral to learning how to regulate affect. And regulating affect is so integral to health, both mental and physical throughout life, whether people are dealing with cardiac disease, psychiatric or psychological disorders. There’s often that common thread of affect regulation. I think the foundations are laid during that first year.”

By Sandra McLean, YFile writer