Rehabilitation with hybrid assistive limb improves upper limb paralysis in patients with cerebral hemorrhage by repairing axonal injury of the corticospinal tract.

Abstract

Objective.Effective rehabilitation for upper limb paralysis in patients with intracerebral hemorrhage mediated by hemiplegia has not yet been established. We evaluated the effectiveness of upper limb functional training using a wearable-type exoskeleton driven by bio-electric signals using upper limb motor function scores and tractography of the corticospinal tract (CST).Approach.Nine patients with putamen and seven with thalamus hemorrhage were trained using the hybrid assistive limb (HAL) of the wearable exoskeleton. Among the participants, 12 individuals were patients with severe hemiplegic, indicated by a Fugl-Meyer assessment (FMA) score of 10. We also investigated the relationship between improvement in upper limb function and changes in mean diffusivity, axial diffusivity, radial diffusivity (RD), or fractional anisotropy (FA) in the CST.Main results.Following HAL training, upper limb function scores increased in all patients. We observed a clinically significant improvement in nine patients, with a mean effect size of 26 ± 12.7. HAL training was effective in improving upper limb function in patients with an FA ratio (the affected/unaffected side) ⩾0.86 in the CST. Patients with clinically significant improvements had a mean 16 ± 15% increase in FA ratio in the CST. Patients with greater improvement in upper-limb function tended to have lower RD values in the CST, and the effect size of the RD value and FMA was demonstrated to be negatively correlated (rs= -0.54). An increase in FA ratio and a decrease in RD values in the CST of the cerebral peduncle are significant findings that suggest improvements in upper limb function.Significance.These findings highlight the effectiveness of HAL training in improving upper-limb dysfunction in patients with subacute cerebral hemorrhage. Improvement of upper limb function by assistive actuation with the wearable exoskeleton based on bio-electric signals may be caused by the promotion of the restoration of white matter integrity of the CST.