title: Estimating the patient's contribution during robot-assisted therapy.
abstract: Robot-assisted therapy has become increasingly common in neurorehabilitation. Sophisticated controllers have been developed for robots to assist and cooperate with the patient. It is difficult for the patient to judge to what extent the robot contributes to the execution of a movement. Therefore, methods to comprehensively quantify the patient's contribution and provide feedback are of key importance. We developed a method comprehensively to estimate the patient's contribution by combining kinematic measures and the motor assistance applied. Inverse dynamic models of the robot and the passive human arm calculate the required torques to move the robot and the arm and build, together with the recorded motor torque, a metric (in percentage) that represents the patient's contribution to the movement. To evaluate the developed metric, 12 nondisabled subjects and 7 patients with neurological problems simulated instructed movement contributions. The results are compared with a common performance metric. The estimation shows very satisfying results for both groups, even though the arm model used was strongly simplified. Displaying this metric to patients during therapy can potentially motivate them to actively participate in the training.
authors.affiliation: Sensory-Motor Systems Laboratory, ETH Zurich, Tannenstrasse 1, TAN E2, 8092 Zurich, Switzerland. marco.guidali@gmail.com
authors.forename: Marco
authors.initials: M
authors.lastname: Guidali
authors.forename: Urs
authors.initials: U
authors.lastname: Keller
authors.forename: Verena
authors.initials: V
authors.lastname: Klamroth-Marganska
authors.forename: Tobias
authors.initials: T
authors.lastname: Nef
authors.forename: Robert
authors.initials: R
authors.lastname: Riener
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D012371:Robotics; D000071939:Stroke Rehabilitation; D019415:Torque; D034941:Upper Extremity