Babies feel pain
A study that contradicts long-held beliefs highlights the importance of giving infants suitable pain relief.
Doctors long believed that infants do not feel pain the way that older children and adults do. Instead, they believed that the infants’ responses to discomfort were reflexes. Based on these beliefs, it was a routine practice to perform surgery on infants without suitable pain relief up until the late 1980s. Even now, infants may receive less than ideal pain relief. For example, a review found that although newborns in intensive care units undergo 11 painful procedures per day on average, more than half of the babies received no pain medications. Some guidelines continue to emphasize that for infants cuddling and feeding are more important sources of comfort than pain-relieving drugs.
There is growing support for better pain control for infants. Doctors and nurses now routinely observe behaviour and physiological responses — such as heart rate — to assess whether infants are experiencing pain. When an infant shows signs of pain, medical staff may give the infant sugar water or other interventions aimed at reducing their distress. However, recordings of brain activity suggest that infants may experience pain without exhibiting physical signs and that sugar water may reduce the behaviours associated with pain but not the pain itself.
More objective measurements of infant pain would be useful, but to create such measurements scientists must first understand how infants experience pain. So Sezgi Goksan and co-workers used a technique called functional magnetic resonance imaging (fMRI) to compare the brain responses of adults and newborns to the same stimulus — a sharp poke of the foot. The adults were also asked about the pain they experienced, and whether the infants pulled their foot away when poked was documented.
The fMRI results revealed that pain increased activity in 20 regions in the adults’ brains, and 18 of the same regions in the infants’ brains. The brain regions activated in the infants’ brains in response to a poke on the foot are involved in processing sensations and emotions. The two regions that did not activate in the infant brains — the amygdala and the orbitofrontal cortex — help individuals interpret the stimuli. Goksan and co-workers therefore conclude that infants experience pain in similar ways to adults, though they may not experience all the emotions that adults have when they are in pain. It is, therefore, important to give infants suitable pain relief during potentially painful procedures.
To find out more
Read the eLife research paper on which this story is based: “fMRI reveals neural activity overlap between adult and infant pain” (April 21, 2015).
Read a commentary on this research paper: “Development: How do babies feel pain?”.
eLife is an open-access journal that publishes outstanding research in the life sciences and biomedicine.