Validation and test of a closed-loop tele-rehabilitation system based on functional electrical stimulation and computer vision for analysing facial expressions in stroke patients

The aim of the present study was to validate and test a closed-loop tele-rehabilitation system for training of hand function and analyzing facial expressions in stroke patients. The paper presents the methods for controlling functional electrical stimulation (FES) to assist hand opening and grasping. The main outcome of the FES control was time differences in grip detections performed by the automatic system and by analysis of the output from force sensing resistors. This time difference was in the range of 0 to 0.8 s. Results from analysis of facial expressions were very variable showing that subjects were disgusted, happy and angry during the exercises, which were not in agreement with the observations made during the experimental sessions.