Although stressful conditions cause infants to have a greater brain response to pain, this experience is not apparent in their behavior. According to new research, stress triggers a disconnect between brain activity and behavior in babies.
“When newborn babies experience a painful procedure, there is a reasonably well coordinated increase in their brain activity and their behavioral responses, such as crying and grimacing,”said study co-author Laura Jones of the University College London. “Babies who are stressed have a larger response in the brain following a painful procedure. But, for these babies, this greater brain activity is no longer matched by their behavior.”
The research team set out to determine if stress causes more pain in babies, which is often the case with adults. The researchers examined 56 healthy newborns, measuring their stress levels based on heart rate patterns and the stress hormone cortisol.
Stress was measured both before and after the babies underwent a minor procedure. Pain response was measured using EEG brain activity and facial expression.
The study showed that babies with higher levels of stress showed a bigger brain reaction to the procedure. This heightened brain activity, however, was not matched by the behavior of the babies.
While the increased brain response to stress did not come as a surprise, the researchers expected that the behavior of the babies would reflect their intensified perception of pain.
According to Laura Jones, the findings of the research reinforce the need to treat and care for babies in ways that minimize both pain and stress. Even though the brain is processing the pain, stressed babies may not appear to be experiencing more pain.
“This means that caregivers may underestimate a baby’s pain experience,” said Jones.
The researchers plan to explore how previous experiences may also influence the way newborns process and respond to pain. The study is published in Current Biology.