Design a soft assistive device for elbow movement training in peripheral nerve injuries

Abstract

In recent years, robotic assistive devices have been widely used to improve the rehabilitation outcome of upper limb disability. Meanwhile in the peripheral nerve injuries disability, the brachial plexus injury (BPI) incidence has increased in developing countries which affects the quality of life for patients due to pain during insufficient arm movement of the patients who go under operative or conservative treatment. Pain will not stop the rehabilitation processes, but may lower the motivation of training. Our ultimate goal is to design a soft assistive device for elbow by developing wearable exoskeleton for promoting restoration of motor function with minimal pain. Pneumatic artificial muscles (PAMs) were applied to our prototype due to the properties which provide high power to weight ratio, light weight and simplicity to install. These actuators were regulated by a controller to perform elbow movements in flexion-extension, and pronation-supination. Furthermore, our work system also measured electromyography (EMG) and pain-related evoked potential (PREP) as estimation of user intended motion and pain feedback control, respectively. We use stimulation device with surface electrode which induced pinprick-like sensation to activate nociceptive fibers and recorded electroencephalography (EEG) on the scalp for measurement of pain during applied device with human arm. Therefore, this 2 degree of freedoms (DoF) assistive device can improve elbow movement while affect the least pain to the wearer.