New Neuromuscular Training for Peripheral Nerve Disorders Using an Ankle Joint Hybrid Assistive Limb: A Case Series

Area of Science:

• Neurology
• Rehabilitation Medicine
• Biomedical Engineering

Background:

• Peripheral nerve disorders in the lower extremities frequently cause drop foot, significantly impairing daily living activities.
• The ankle joint hybrid assistive limb (HAL) is a device designed to facilitate voluntary ankle joint training using bioelectrical signals from lower extremity muscles.

Purpose of the Study:

• To investigate the neurological effects of ankle joint HAL training in patients with peripheral nerve disorders.
• To evaluate the impact of HAL training on neuromuscular function, including muscle activation and nerve signal potentials.

Main Methods:

• Three patients with peripheral nerve disorders underwent a 2-week inpatient rehabilitation program with daily ankle joint HAL training sessions.
• Nerve conduction studies (Sensory nerve action potentials and Compound muscle action potentials) and surface electromyography (EMG) were performed before and after the training period.
• Manual Muscle Testing (MMT) was used to assess muscle strength changes.

Main Results:

• All patients exhibited severe neuromuscular impairment based on Compound muscle action potential (CMAP) results.
• Integrated EMG measurements of antagonistic muscle activities decreased post-HAL training.
• Manual Muscle Testing (MMT) scores showed slight improvements in specific muscles for two patients, indicating enhanced muscle function.

Conclusions:

• Ankle joint HAL training may facilitate voluntary ankle movements by reducing antagonistic muscle co-contraction through computer processing.
• The rehabilitation approach shows potential for enhancing muscle movement, coordination, and motor learning in patients with neuromuscular deficits.
• Despite severe impairment, HAL training demonstrated positive effects on muscle function and coordination.