A screaming baby is a pretty good sign something is wrong, but at the same time it is a fairly arbitrary measure. Where is the pain? How bad is it? Is this medicine working? Answer me! Scientists at the University of Oxford have been working on a more precise way of doing things, using brainwave recordings to uncover a signature that appears indicative of infant pain, which can then help gauge infant response to pain relief.

Pediatricians do have ways of assessing infant pain, but these are inexact. Because they obviously cannot speak, babies don't use words or numbers to rate pain in the way a more mature person could. So doctors instead go by facial expressions and heart rates to determine the childrens' level of suffering.

In search of a clearer metric, the Oxford researchers studied the brain activity of 18 infants as they underwent a heel-lance procedure for blood-screening. They did this through the use of electroencephalographic (EEG) recordings, which is a non-invasive method that places electrodes on the scalp to measure electrical signals emitted from the brain.

The team wound up with what it said was an EEG signature that represented pain, which they then validated through four additional studies involving a further 72 babies. This signature seemed to match up with conventional methods of pain-measuring, such as facial grimacing. It also proved to be distinct from the brain signals emitted in response to other stimuli, like sounds and flashing lights.

What's more, when a local anesthetic was applied to the babies' skin, the signals were reduced. This suggests that the approach can be used to test the effectiveness of pain-relieving drugs in infants. This is particularly important because measuring dosages for infants, who metabolize drugs differently than adults, can be problematic.

With further development, the researchers hope that the approach can be refined and used for individual pain assessments. Rebecca Slater, one of the authors of the study, says that babies in neonatal units each undergo 10 or 12 painful procedures on average, so boosting the effectiveness of pain relief in those circumstance would be an important step forward.

You can hear from Slater in the video below, while the research was published in the journal Science Translational Medicine.