Development and Evaluation of a Novel Portable Robotic Gait Rehabilitation Platform in Older Chronic Stroke Survivors (Phase 2)

This will be a prospective single blind randomized control trial where investigators propose to recruit a maximum of 100 older chronic stroke patients (age 50 years to 90 years old) with mild to severe lower limb motor function impairment.

Recruited subjects will have 19 study visits. The recruited 100 subjects will be divided into 2 groups of 50 each through a simple randomization scheme; 1) Conventional gait training (CT, control group) and 2) Gait rehabilitation with the new walker modified after 1st stage (WT, experimental group). Each subject will undergo training programs consisting of 45 minutes training session (excluding rest periods), 3 days (alternate) a week for 6 consecutive weeks.

Subjects allocated to the CT group will receive physiotherapy program, including active assisted or passive range of motion and conventional gait and balance training. The subjects will first perform active assisted or passive range of motion of the lower limbs including ankle, knee, and hip joint in the supine position for 10 minutes. Subjects will then perform conventional gait and balance therapy based on the proprioceptive neuromuscular facilitation (PNF) concept for 15 minutes. Among the PNF techniques, investigators will facilitate pelvic motion to improve control and mobility of the subjects. Subjects will be given a 5 minutes rest. Finally, the CT subjects will undergo the over-ground gait training with or without aid or orthoses and with manual assistance from senior physiotherapist for 15 minutes, depending on the individual subject's abilities.

For WT group, subjects will first go through active assisted or passive range of motion of the lower limbs including ankle, knee, and hip joint in the supine position for 10 minutes. The main therapy consists of 2 parts with 5 minutes rest in between. During part 1, subjects will be trained on the robotic walker with the help of active body weight support (BWS) and functional electrical stimulation (FES) for 15 minutes with pelvic motion support function and lateral balance function being continuously provided. The level of BWS will be provided as much as the subjects can support his or her residual body weight (10% to 30% BWS). The BWS force will be gradually reduced as soon as the subjects can support his or her full body weight. The clinical criterion for the reduction is that the subjects show the ability to move his or her hips and are able to support his or her own body weight sufficiently on the affected lower limb and straighten their legs during the single-leg stance phase. Therapists will be able to control the level of BWS force according to the criteria mentioned above. FES will be used to stimulate the peroneal nerve in the affected side, and the intensity of the device will be painlessly controlled by allowing sufficient dorsiflexion and eversion during the swing phase. FES will be set to synchronize with the inertial measurement unit (IMU) sensors and the stimulation timing for the common peroneal nerve will based on the detected gait phase by IMU sensors. During part 2, subjects will also receive resistance/assistance forces on top of the BWS and FES training for 15 minutes. The decision on providing resistance or assistance modes will be made according to the subjects' functional ambulation category (FAC) level. For subjects with FAC level less than 3, the assistive function will be implemented, otherwise resistive function will be applied. The assistance and resistance forces will be applied proportional to the BW of the subjects (2% to 7% of BW), which is determined by therapists. The rationale of dividing the WT group into 2 parts of different training is that the 1st part is to provide basic locomotive function with persistent and repetitive sensory stimulation while the 2nd part is to add task-specificity to improve weight-bearing, aerobic, functional strengthening and balance for the neurologically challenged patients by implementing a variety of walking tasks. Investigators expect that the repetitive and persistent walking with task-specific gait training will promote better functional outcomes than the conventional gait therapy.

During the session, subjects can request for a rest anytime if they experience discomfort or fatigue. Additionally, investigators will provide them with a 5 - 15 minutes of rest time. The rest period given depends on individual subjects' needs. Investigators will seek their opinion whether subjects have enough rest and are well to continue with the session. Longer rest period will be given to the subjects who require them. During the resting period and also the period where subjects are not required to participate, a chair will be provided for the subject to sit and rest.