Development of a New Ankle Joint Hybrid Assistive Limb

Abstract

Foot and ankle disabilities (foot drop) due to common peroneal nerve palsy and stroke negatively affect patients’ ambulation and activities of daily living. We developed a novel robotics ankle hybrid assistive limb (HAL) for patients with foot drop due to common peroneal nerve palsy or stroke. The ankle HAL is a wearable exoskeleton-type robot that is used to train plantar and dorsiflexion and for voluntary assistive training of the ankle joint of patients with palsy using an actuator, which is placed on the lateral side of the ankle joint and detects bioelectrical signals from the tibialis anterior (TA) and gastrocnemius muscles. Voluntary ankle dorsiflexion training using the new ankle HAL was implemented in a patient with foot drop due to peroneal nerve palsy after lumbar surgery. The time required for ankle HAL training (from wearing to the end of training) was approximately 30 min per session. The muscle activities of the TA on the right were lower than those on the left before and after ankle HAL training. The electromyographic wave of muscle activities of the TA on the right was slightly clearer than that before ankle HAL training in the resting position immediately after ankle dorsiflexion. Voluntary ankle dorsiflexion training using the novel robotics ankle HAL was safe and had no adverse effect in a patient with foot drop due to peroneal nerve palsy.

Robot-Assisted Ankle Rehabilitation Using the Hybrid Assistive Limb for Children after Equinus Surgery: A Report of Two Cases

“…Assist gain levels range from 0 (unassisted) to 100, thus allowing the controller to adjust the balance between flexion and extension at each level. The controller also has a monitor that displays the BES of the flexor and extensor muscles [ 15 , 16 ].…”

“…A new ankle joint unit that makes it possible to perform ankle joint exercises has been developed as an accessory for the HAL-SJ ( Figure 1 ). Ankle rehabilitation using the HAL-SJ has been attempted for adult patients with drop foot, and improvements in muscle activity, strength, and walking speed have been reported [ 15 , 16 ]. However, the results of the use of the HAL-SJ for pediatric patients who have undergone equinus surgery have not yet been reported.…”

Robotic Technology in Foot and Ankle Surgery: A Comprehensive Review

“…Examples of these robotic devices include a feedback-controlled and programmed stretching device, virtual reality robots, portable rehab robots with computer games, and the Rutgers ankle, among others ( Table 3 ). The Rutgers ankle is a haptic interface platform first introduced in 1999 that communicates with a personal computer, running game-like virtual reality exercises that allow full range of ankle motion [ 65 ]. However, the studies documenting outcomes after these interventions had varied protocols and measured different motion outcomes, making comparison difficult.…”

Gait Biomechanics for Fall Prevention among Older Adults

“…It is a motor-driven exoskeleton system to produce the wearer's intended motions through the actuation of HAL's motors by converting efferent neuro-signals, whether erratic or faint, into tangible movements that meet the intention of its wearer through processing. (Figure 7) [88]. While this type of wearable cyborg can assist people while it's being worn, it can re-establish the lost connection between the efferent motor signals and the afferent sensory signals of the body's ori ginal biofeedback loop of patients with severe movement dysfunctions (e.g., spinal cord injury, post-stroke syndromes), by acting as a non-invasive external medium through coupling with the 'intention movement` of the wearer (i.e., interactive biofeedback theory).…”