Kinematic cues for the categorization of pointing movements made by hemiparetic stroke patients

Abstract

Our visual sensitivity to human movements is illustrated by our ability to recognize actions even with a minimal visual display. The present study investigates if professional expertise influences the precision of recognition and the visual cues used. We presented movements made by hemiparetic stroke patients and healthy subjects to expert (physicians and physiotherapists) and naive observers. Since stroke induces perturbations of hand trajectory and interjoint coordination, we presented two types of computer animation (one dot representing the hand and stick diagram of the upper body). The observers had to score the pathological character of the movements. The observers were able to differentiate patients according to their impairment level. The experts responded faster but, surprisingly, their responses did not differ from those of naive observers. The subjective judgment relied mainly on the quality of hand trajectory. The weak influence of postural information should be confirmed with more realistic displays.