As recently as the 1980s, scientists thought that babies barely process pain. But over the past decade neuroscientists have confirmed that infants indeed feel pain, and that they may be even more sensitive than adults. One problem with studying pain management in babies, however, is that they cannot tell us whether the interventions are working.
Now, thanks to a new brain-scanning technique, that may be about to change. Researchers have begun mapping pain in infant brains, and suspect that soon they’ll be able to use electroencephalographs (EEGs) to determine whether babies are in pain. “We characterized a ‘template’ of this pain-related brain activity, then looked at how the pain-related brain activity changed if local anesthetic was applied,” Dr. Caroline Hartley, a postdoc at Oxford University’s Department of Pediatrics, explained to Fatherly.
Hartley and her team used EEG technology to track the brain patterns of 18 healthy, full-term infants who were exposed to painful stimuli—a heel prick procedure routinely used to obtain infant blood samples, for instance—and painless stimuli, such as flashing lights. The researchers found that painful procedures produced large, identical EEG responses in 12 out of 18 babies. This was true even in absence of grimacing, the classic measurement of infant discomfort. Painless procedures elicited no such effect.
When Hartley and colleagues repeated the experiment, this time after giving infants an analgesic numbing cream, they found that “the pain-related brain activity was significantly reduced by local anesthetic,” Hartley says. This suggests that this neurologic template could help test how well anesthetics work on babies.
There are a few caveats. First, the study still needs to be replicated with a large sample—18 babies is far too few to draw meaningful conclusions. Hartley also noted that the method is not yet sensitive enough to determine whether an individual infant is in pain.
Instead, Hartley says, the template should be used to help researchers discover how large groups of infants respond to different interventions. Dr. Rebeccah Slater, also a coauthor on the study, is currently using it in the Procedural Pain in Premature Infants (Poppi) trial, to test if morphine works for babies during invasive medical procedures.
“We also plan to use this measure to investigate whether gently stroking a baby before a procedure, like a blood test, will reduce the pain-related brain activity,” Hartley says.