Effect of reducing assistance during robot-assisted gait training on step length asymmetry in patients with hemiplegic stroke A randomized controlled pilot trial

Background: An assist-as-needed robot-assisted gait training protocol was recently developed. It allows active movement during training, but its exact criteria remain unknown. Asymmetric step length is a common abnormal gait pattern in hemiplegic stroke patients. We compared the effects of assist-as-needed robot-assisted gait training on the unaffected and affected limbs of hemiplegic stroke patients. Method: Twenty-four chronic stroke patients with asymmetric step lengths were randomly assigned to 1 of 2 groups. Twelve completed the study protocol. Group 1 underwent 20 sessions of assist-as-needed robot-assisted gait training for the unaffected limb and fully-assisted robot-assisted training for the affected limb. Group 2 underwent 20 sessions of robot-assisted gait training using the opposite protocol. Clinical measurements were obtained and 3-dimensional gait analyses were performed at baseline and after 10 and 20 training sessions. Results: Clinical measurements improved in both groups after 20 training sessions. The unaffected limb’s step length asymmetry ratio and hip maximal extension moment significantly improved in group 1. The affected limb’s maximal dorsiflexion angle for the ankle in the swing phase significantly improved in group 2. Conclusion: Application of the assist-as-needed training mode for the unaffected limb helped improve step length asymmetry in chronic stroke patients. Abbreviations: AAN = assist-as-needed mode, ankle dorsiflexion = maximal ankle dorsiflexion in stance phase, ankle dorsiflexion’ = maximal ankle dorsiflexion in swing phase, ankle moment = maximal ankle moment, ankle power = maximal ankle power, FA = fully assisted mode, FAC = functional ambulation category, FMLE = Fugl–Meyer motor assessment of the lower extremity, hip extension = maximal hip extension in stance phase, hip flexion = maximal hip flexion in swing phase, hip moment = maximal hip moment, hip power = maximal hip power, knee extension = maximal knee extension in stance phase, knee flexion = maximal knee flexion in swing phase, knee moment = maximal knee moment, knee power = maximal knee power, MI = motricity index of the lower extremity, NIHSS = NIH stroke scale, RAGT = robot-assisted gait training, T0 = before training, T1 = after 10 sessions, T2 = after 20 sessions, TCT = trunk control tests.