Kinematic and EMG patterns evaluation of upper arm reaching movements

Variations in kinematic performances and muscle activations, underlying improvements in muscle function and strength, in response to upper arm training of patients with congenital or acquired brain injuries, are still poorly understood. One of the most interesting features of a robot-mediated therapy is the ability to quantify the performance of the rehabilitation tasks proposed to the patient. Although the shoulder is the most complex joint in the body, both for the range of freedom of movements and for the muscular-tendon structure, not so many commercial or research devices have been proposed to study its movements and no study have proposed a standardized, quantitative kinematic and electromyographic assessment. This study aimed to develop a quantitative assessment of kinematics and electromyographic pattern of the arm´s muscles involved in reaching robot-assisted movements by means of indices effectively describing the main pattern features in ten normal subjects. Each subject underwent a specific eight sequences motor task protocol. The system automatically classify each movement detecting its start/end times, extract main kinematic indexes plotting activation and deactivation graphs related to eight emg channels. Results showed that particularly movement smoothness indexes and timing of emg patterns may provide an effective upper arm reaching movement assessment.