Pattern of improvement in upper limb pointing task kinematics after a 3-month training program with robotic assistance in stroke

Background: when exploring changes in upper limb kinematics and motor impairment associated with motor recovery in subacute post stroke during intensive therapies involving robot-assisted training,it is not known whether trained joints improve before non-trained joints and whether target reaching capacity improves before movement accuracy. methods: twenty-two subacute stroke patients (mean delay post-stroke at program onset 63 ± 29 days,m2) underwent 50 ± 17 (mean ± sd) 45-min sessions of robot-assisted (inmotion™) shoulder/elbow training over 3 months,in addition to conventional occupational therapy. monthly evaluations (m2 to m5) included fugl-meyer assessment (fm),with subscores per joint,and four robot-based kinematic measures: mean target distance covered,mean velocity,direction accuracy (inverse of root mean square error from straight line) and movement smoothness (inverse of mean number of zero-crossings in the velocity profile). we assessed delays to reach statistically significant improvement for each outcome measure. results: at m5,all clinical and kinematic parameters had markedly improved: fugl-meyer,+65% (median); distance covered,+87%; mean velocity,+101%; accuracy,+134%; and smoothness,+96%. delays to reach statistical significance were m3 for the shoulder/elbow fugl-meyer subscore (+43%),m4 for the hand (+80%) and m5 for the wrist (+133%) subscores. for kinematic parameters,delays to significant improvements were m3 for distance (+68%),velocity (+65%) and smoothness (+50%),and m5 for accuracy (+134%). conclusions: an intensive rehabilitation program combining robot-assisted shoulder/elbow training and conventional occupational therapy was associated with improvement in shoulder and elbow movements first,which suggests focal behavior-related brain plasticity. findings also suggested that recovery of movement quantity related parameters (range of motion,velocity and smoothness) might precede that of movement quality (accuracy). trial registration: eudract 2016-005121-36. date of registration: 2016-12-20. date of enrolment of the first participant to the trial: 2009-11-24 (retrospective data). © 2017 the author(s).