A control and a post-stroke subject with right-side chronic hemiparesis were studied. The post-stroke subject underwent 30 sessions of balance-perturbed training while walking on an instrumented treadmill where the Balance Assessment Robot (BAR™) randomly delivered pushes to pelvis in various directions at various speeds and at various perturbation amplitudes. The investigators assessed kinematics, kinetics, electromiography and spatio-temporal responses to outward-directed perturbations commencing either at foot contact of the left or the right leg.
For a detailed description of the study, see the Arms and Interventions section.
- Balance Assessment Robot (BAR™) Device
Intervention Desc: The BAR™ has got six degrees of freedom (DOF) that interface to the pelvis of a walking subject. Five DOFs (translation of pelvis in sagittal, lateral and vertical directions; pelvic rotation and pelvic list) are actuated and admittance-controlled, providing transparent haptic interaction with negligible power transfer; the remaining DOF (pelvic tilt) is passive. The BAR™ is capable of delivering perturbations in the directions forward/backward and left/right, but for the purpose of this study only "outward" perturbations in the frontal plane were considered. ARM 1: Kind: Experimental Label: Case - stroke survivor Description: Stroke survivor, 6mon post stroke resulting in right-sided hemiparesis, 53yrs old, had completed a 2mon rehabilitation program prior to the study. He underwent 30 training sessions with the Balance Assessment Robot (BAR™) within a 10-week period, each consisting of 10-15min of unperturbed treadmill and 30-45min of perturbation training. Perturbations were delivered in the forward, backward, left and right direction, occurring every 6sec, at the left leg initial contact and the right leg initial contact. Two training sessions were spent to determine adequate treadmill speed (0.4m/s) and perturbation amplitude (60N), followed by the first assessment session. After the last training session, assessment was repeated using the same parameters plus 90N perturbation amplitude. ARM 2: Kind: Experimental Label: Control - matched healthy subject Description: Healthy male, height- and weight-matched to the Case. He was assessed according to the same protocol as the Case using the Balance Assessment Robot (BAR™) at perturbation amplitudes 60 and 90 N.
|Type||Measure||Time Frame||Safety Issue|
|Primary||Change in centre of mass of the Case||Assessment at session no. 3 (during week 1) and session no. 30 (during week 10)|
|Primary||Change in centre of pressure of the Case||Assessment at session no. 3 (during week 1) and session no. 30 (during week 10)|
|Primary||Change in ground reaction force of the Case||Assessment at session no. 3 (during week 1) and session no. 30 (during week 10)|
|Secondary||Centre of mass of the Control||During the only session (i.e., session 1 on day 1)|
|Secondary||Centre of pressure of the Control||During the only session (i.e., session 1 on day 1)|
|Secondary||Ground reaction force of the Control||During the only session (i.e., session 1 on day 1)|