Adaptation of upper limb movement using exoskeleton-based training and transfer of cinematic patterns to unconstrained movement: A preliminary study

International audienceIntroduction/BackgroundRobotic technologies offer the possibility for highly specific training of upper limb movements. How exactly the motor coordination imposed during an intervention carries over into unconstrained upper limb activity, however, remains poorly understood. This preliminary study sought to examine the after effects of robotic training on upper limb joint kinematics during reaching.Material and methodUsing a four-degree of freedom upper limb exoskeleton, healthy adult subjects trained on a series of reaching tasks. Shoulder and elbow joint coordination was modified using a viscous corrective force field. Kinematic variables during the different reaching tasks without the robotic device were evaluated using a motion capture system prior to and following the intervention. Movement adaptation was evaluated with respect to subject performance on reaching toward experimental targets as well as untrained targets.ResultsShoulder abduction profiles and terminal elbow position appeared modified two hours following the training. These changes reflected the joint kinematics forced during the robotic intervention. Furthermore, distance metrics based upon principal components analysis indicated that exposure to the corrective force field had durable effects upon shared coordination between the shoulder and elbow. This shift in movement patterns was observed for both the experimental and untrained targets.ConclusionThese preliminary results suggest that certain features of upper limb movement, trained using corrective force fields in an exoskeleton, may be retained following the intervention and potentially generalised to prehensile movements in the peripersonal workspace