Upper limb robot-assisted training after severe paresis in subacute stroke: An innovative paradigm to track motor performance

Abstract

Objective.- The present study investigated patient/robot interactions within an upper limb robot-assisted training in subacute stroke patients. Methods.- Nineteen subacute stroke survivors (8 females; age 53+/-17 [19-83] years; time from stroke, 49+/-19 days) with severe upper limb paresis (mean Fugl-Meyer Assessment score, 17+/-7/66 or mean Motricity Index 41+/-2/100) carried out 16 sessions (3/week, 35 days) of robot-assisted shoulder/elbow training (InMotion 2.0, IMT, Inc., MA, USA) combined with standard therapy. The values of three parameters (Guidance, Robot Power and time allotted to close the slot) were analysed and compared after the 80th movement performed at S1, S4, S8, S12 and S16 (ANOVA, post-hoc Tukey). Results.- The time alloted to close the slot decreased at S4 (P = 0.038) when we observed a decrease in guidance only at S16 (P = 0.026). The Robot Power remained unchanged until S16. Discussion.- This study demonstrated that some robotic device enables the quantification of both patient's participation and motor recovery strategies. The results showed that recovery process followed the classical speed/accuracy trade-off, with an improvement of speed before accuracy at a constant force supplied by the robot.