Gait training using a stationary, one-leg gait exercise assist robot for chronic stroke hemiplegia: a case report

Abstract

[Purpose] The Gait Exercise Assist Robot (GEAR) is a stationary, one-leg robot for gait training. The purpose of this case study was to evaluate the efficacy of rehabilitation using GEAR training for chronic stroke hemiplegia. [Participant and Methods] The participant was a 66-year-old male stroke survivor with left hemiparesis due to a right putaminal hemorrhage. He could walk slowly under supervision, although his gait had a constant forward trunk lean, with flexed knee, and a lack of hip extension movement on the affected side. Gait training using GEAR and physical therapy were performed for 14 days. Under both training conditions, the physical therapist made the participant conscious of extension movement of the hip joint in the affected-side stance phase. The robotic assistance was adjusted to maximize voluntary movement while observing gait. Physical function and gait ability parameters were evaluated before and after training. [Results] After training, extension motion of the hip joint increased in the affected-side stance phase, and body weight was transferred smoothly onto the affected-side limb, leading to an improvement in gait speed. [Conclusion] Gait training using GEAR and physical therapy may improve gait pattern and speed in patients with chronic stroke hemiplegia.

Keywords: Chronic stroke hemiplegia; Gait training; Robot.

Fig. 1.

Gait Exercise Assist Robot (GEAR) system. The components of the GEAR system include a knee-ankle-foot robot, a low floor treadmill, a safety suspension device (can be used for bodyweight support), a robot weight-support device, a monitor for patient use, and a control panel. The knee-ankle-foot robot with a knee actuator attached to the affected leg weighs approximately 5.7 kg, and is worn only on the hemiplegic limb. The robot weight-support device cancels the weight of the knee-ankle-foot robot so that the patient does not feel its weight. The foot sole of the robot is equipped with load sensors to measure foot load. The system determines the gait cycle from the load sensor information and the knee joint angle, and executes flexion and extension of the knee joint at the appropriate timing. The knee extension assist level and the swing assist level can be adjusted from the control panel. The knee extension assist provides the knee joint extension torque during the stance phase and can be set from level 10 (maximum) to level 1 (minimum). The swing assist provides swing motion support for the affected leg by controlling the robot weight-support force and can be set from level 6 (maximum) to level 1 (minimum). Also, there is a versatile visual and auditory feedback function.

Fig. 2.

Hip, knee, and ankle joint angles (A) and moments (B) in the sagittal plane before and after training. Solid lines indicate the joint angles and moments before training and dashed lines indicate those after training. Positive joint angle values represent flexion and dorsiflexion. Negative joint angle values represent extension and plantarflexion. Positive joint moment values represent the extension and plantarflexion of force. Negative joint moment values represent the flexion and dorsiflexion of force.