EPAT General Discussion, page-80

This is the original evaluation study done in 2015 that shows that just the facial recognition aspect of the App can detect the presence of pain in people.
http://www.epattechnologies.com/wp-content/uploads/2017/04/3104-Evaluation-A4-Flyer.pdf

Are facial expressions in people as measured by micro expressions using this technology fairly constant from childhood through to adulthood? If true this makes the science easier.

Then to get the App approved for pre-verbal children they just have to correlate current technology (Abbey pain scale I think) with the ePAT App just as they did for dementia patients. Probably worth asking PD.