Characterizing the human-robot haptic dyad in robot therapy of stroke survivors

Purpose–The working hypothesis,on which this paper is built,is that it is advantageous to look at protocols of robot rehabilitation in the general context of human-robot interaction in haptic dyads.The purpose of this paper is to propose a new method to detect and evaluate an index of active participation(AC index),underlying the performance of robot-assisted movements.This is important for avoiding the slacking phenomenon that affects robot therapy.Design/methodology/approach–The evaluation of the AC index is based on a novel technique of assistance which does not use constant or elastic forces but trains of small force impulses,with amplitude adapted to the level of impairment and a frequency of 2 Hz,which is suggested by recent results in the field of intermittent motor control.A preliminary feasibility test of the proposed method was carried out during a haptic reaching task in the absence of visual feedback,for a group of five stroke patients and an equal group of healthy subjects.Findings–The AC index appears to be stable and sensitive to training in both populations of subjects.Originality/value–The main original element of this study is the proposal of the new AC index of voluntary control associated with the new method of pulsed haptic interaction.

Upper limb bilateral symmetric training with robotic assistance and clinical outcomes for stroke A pilot study

Purpose–The purpose of this paper is to evaluate the physiotherapeutic benefits of bilateral symmetric training(BST)for stroke survivors affected by hemiparesis.Design/methodology/approach–Other studies have investigated symmetric physiotherapy.A key difficulty in previous work is in maintaining mirror-imaged trajectories between the affected and less-affected limbs.This obstacle was overcome in this work by using a two-armed robotic exoskeleton to enforce symmetry.In total,15 subjects,W6 months post stroke were,randomly assigned to bilateral symmetric robotic training,unilateral robotic training,and standard physical therapy.Findings–After 12 training sessions(90 minutes/session),the bilateral training group had the greatest intensity of movement training.They also had the greatest improvement in range of motion at the shoulder.The unilateral training group showed the greatest reduction in spasticity.Research limitations/implications–The rationale for symmetric physiotherapy is that it might promote connections from the undamaged brain hemisphere.The robot generated copious amounts of detailed kinematic data.Even though these data provided insights into the human to machine interface using different training modalities,it proved difficult to draw neurological conclusions.It is recommended that future research along these lines should include measures of neurophysiological change and/or changes in neurological activity.Practical implications–This research suggests that the advantage of bilateral symmetric movement over other modalities is slight,and that robotic training has comparable results with standard care.If BSTis used,care is potentially needed toavoid exacerbation of spasticity.Finally,this research includes a novel quantitative approach for evaluating robotic training.Originality/value–This study is of value to therapeutic researchers interested in new physiotherapy techniques,roboticists interested in developing rehabilitation devices,or for rehabilitation game designers interested in using virtual reality.