Non-Paretic Arm Motor Deficit and Recovery as a Function of Damage Lateralization after Stroke: Biomechanical Study

Abstract

The aim was to study the dependence of post stroke motor impairments of the paretic and the intact arm of lesion lateralization and paresis severity. The influence of lateralization of the lesion and the severity of paresis on the recovery of motor functions after rehabilitation using a hand exoskeleton controlled by a brain-computer interface was also studied. The study included 24 patients, 12 with left hemisphere involvement and 12 with right hemisphere involvement. Each group included 6 patients with moderate paresis and 6 patients with severe paresis. As motor tests, isolated movements in the joints of the paretic and intact hands were used before and after the rehabilitation course. Joint torque and motion isolation degree were used to assess motor function. It is shown that the muscle moments of the intact arm are greater in the case of damage to the left hemisphere; the asymmetry of the moments in the joints in this case was more pronounced than in the case of damage to the right hemisphere. This may be due to a greater imbalance in the activity of the hemispheres. The effectiveness of rehabilitation was manifested in: 1) an increase in moments in the joints in both paretic and intact hands; 2) an increase in the symmetry of the biomechanical parameters of the paretic and intact hands, which may indicate the restoration of the balance of the activity of the hemispheres. Biomechanical analysis of isolated movements allows suggests the pronation-supination in the vertical position of the arm as a sensitive indicator of motor function recovery after stroke.