Robotic ankle control can provide appropriate assistance throughout the gait cycle in healthy adults.

Ankle foot orthoses are mainly applied to provide stability in the stance phase and adequate foot clearance in the swing phase; however, they do not sufficiently assist during the entire gait cycle. On the other hand, robotic-controlled orthoses can provide mechanical assistance throughout the phases of the gait cycle. This study investigated the effect of ankle control throughout the gait cycle using an ankle joint walking assistive device under five different robotic assistance conditions: uncontrolled, dorsiflexion, and plantar flexion controlled at high and low speeds in the initial loading phase. Compared with the no-control condition, the plantar flexion condition enhanced knee extension and delayed the timing of ankle dorsiflexion in the stance phase; however, the opposite effect occurred under the dorsiflexion condition. Significant differences in the trailing limb angle and minimum toe clearance were also observed, although the same assistance was applied from the mid-stance phase to the initial swing phase. Ankle assistance in the initial loading phase affected the knee extension and ankle dorsiflexion angle during the stance phase. The smooth weight shift obtained might have a positive effect on lifting the limb during the swing phase. Robotic ankle control may provide appropriate assistance throughout the gait cycle according to individual gait ability.

Short-term effect of a close-fitting type of walking assistive device on spinal cord reciprocal inhibition.

One of the major problems with walking encountered by patients with spastic hemiplegia is diminished toe clearance due to spasticity of their leg muscles. To improve their walking, a specialized robot assist for ankle movements (RE-Gait) has been utilized. The present study examined the neurophysiological effects whether spinal cord reciprocal Ia inhibition (RI) in the leg was altered by using RE-Gait. Sixteen patients with a clinical diagnosis of stroke were divided into the two groups, RE-Gait walking group (Group R) and normal (controlled) walking group (Group C). In each group, they walked on a flat floor for 15 min with or without RE-Gait. The depression of soleus (Sol) H-reflexes conditioned by common peroneal nerve stimuli with the conditioning-test (C-T) intervals of 1, 2, 3, and 4 ms were assessed before and immediately after each walking session. After the intervention, the LSM (SE) of Sol H-reflex amplitude with 1, 2 and 3 ms C-T interval conditions were significantly decreased in group R (1 ms: 88.15 (4.60), 2 ms: 86.37 (4.60), 3 ms: 89.68 (4.62)) compared to group C (1 ms: 105.57 (4.56), 2 ms: 100.89 (4.58), 3 ms: 107.72 (4.58)) [1 ms: p = 0.012, 2 ms: p = 0.035, 3 ms: p = 0.011]. Walking assistive robot that targets ankle movements might be a new rehabilitation tool for regulating spinal cord excitability.