Functional Rehabilitation using the Hybrid Assistive Limb Exoskeleton: A First Experience in the United States

Objectives: The Hybrid Assistive Limb (HAL, Cyberdyne, Japan) exoskeleton facilitates voluntary, user-driven gait patterns through an electromyography-triggered neuromodulatory feedback system. This allows for the repeated execution of physiological gait patterns, crucial to recovery in cases of neurologic motor deficit. In this series, we present the first three patients (3 additional patients will be finishing their follow-up within the next few weeks) in the United States to undergo HAL rehabilitation training.

Methods: A case series of three patients participating in a single-center prospective, interventional pilot study, who were suffering different neurologic motor deficits. Inclusion criteria included patients who had achieved a stable non-progressive state in their motor neurologic deficit following (a) spinal cord injury with ASIA A through D functional status with thoracic and lumbar levels of paralysis (b) cervical spinal cord injury with incomplete injuries below C6, or (c) CVA, MS, or other neurodegenerative disorders. Patients on active medications for spasticity were required to be on a stable dose for at least three months prior to study entry. The patients underwent 60 sessions of Body Weight-Supported Treadmill Training (BWSTT) in the HAL exoskeleton over the course of 12 weeks. Measures of functional ambulation (10 meter walk test) were performed out of the HAL exoskeleton before and after each session, and at the 12-week and 6-month follow-up. Timed Up & Go (TUG) test was performed each week. Treadmill data (time, distance, blood pressure, heart rate) while in HAL was recorded at each session. Measures of endurance (six-minute walk test), risk of falling (TUG), balance impairment (Berg Balance Scale), and improvements in walking performance (Walking Index for Spinal Cord Injury II score (WISCI II)) were measured at baseline, 12-weeks training and 6-month follow-up.

Results and Conclusion: All three patients completed 60 visits. All patients achieved markedly increased treadmill paces, increased WISCI II scores, increased distance in the six-minute walk test, and decreased TUG times at 6-month follow-up. In the 10 meter walk test, all patients achieved a significant decrease in time and steps, and showed improvements in the required assistance level to perform the test. Patients 1 and 3 showed improvement on the Berg Balance Scale while patient 2 had no change between baseline and 6-month follow-up. Only minor adverse effects were reported, including skin abrasions and irritation secondary to chaffing of the HAL unit and EMG electrodes.

These data show that HAL training is both feasible and effective in the rehabilitation of patients suffering neurologic motor deficits secondary to trauma and/or pathological/neurodegenerative processes who have achieved a stable non-progressive state for three or more months A greater number of patients are required to meaningfully assess the effectivenss of this modality and determine if specific pathologies respond greater than others.

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Publication History

Article published online:
15 October 2020