Pain assessment in infants: Towards spotting pain expression based on infants´ facial strain

We report novel results of utilizing infant facial tissue distortion as a pain indicator in video-sequences of ten infants based on analysis of facial strain. Facial strain, which is used as the main feature for classification, is generated for each facial expression and then used to train two classifiers, k Nearest-Neighbors (KNN) and support vector machine (SVM) to classify infants´ expressions into two categories, pain and no-pain. The accuracy of binary classification for KNN and SVM was 96% and 94% respectively, based on ten video sequences. The results of this study are encouraging; they indicate that assessing pain based on facial displays is a promising area of investigation, and open new directions for future work.