A Sonomyography-based Muscle Computer Interface for Individuals with Spinal Cord Injury

Impairment of hand functions in individuals with spinal cord injury (SCI) severely disrupts activities of daily living. Recent advances have enabled rehabilitation assisted by robotic devices to augment the residual function of the muscles. Traditionally, non-invasive electromyography-based peripheral neural interfaces have been utilized to sense volitional motor intent to drive robotic assistive devices. However, the dexterity and fidelity of control that can be achieved with electromyography-based control have been limited due to inherent limitations in signal quality. We have developed and tested a muscle-computer interface (MCI) utilizing sonomyography to provide control of a virtual cursor for individuals with motor-incomplete spinal cord injury. We demonstrate that individuals with SCI successfully gained control of a virtual cursor by utilizing contractions of muscles of the wrist joint. The sonomyography-based interface enabled control of the cursor at multiple graded levels demonstrating the ability to achieve accurate and stable endpoint control. Our sonomyography-based muscle-computer interface can enable dexterous control of upper-extremity assistive devices for individuals with motor-incomplete SCI

Development and Trial of a Multipurpose Customized Orthosis for Activities of Daily Living in Patients with Spinal Cord Injury

People with mid-cervical spinal cord injury (SCI) often have difficulty in performing activities of daily living due to weakness or paralysis in the flexor muscles. The inability to perform activities requiring fine motor control, such as eating, brushing, writing, unlocking doors, etc., affects overall quality of life negatively. To perform such tasks, appropriate movement of the hands, specifically at the wrist, is essential. For SCI patients, wrist orthotics are considered a viable option with which to perform general tasks. Wrist orthotics, used for rehabilitating people with SCI, help to maintain proper wrist and hand positioning; however, patients must frequently change these orthotic devices as per separate activity requirements. This becomes difficult and cumbersome for such patients. In this work, a passive 3D-printed upper-extremity dynamic orthosis was developed to assist SCI patients in their activities of daily living. The orthosis works on the principle of a worm-gear-based mechanism to produce pronation/supination motions at the wrist. To test the developed multipurpose customized orthosis, ten patients with cervical SCI were recruited and prescribed the 3D-printed splint for a period of four weeks. It was assessed through the QUEST questionnaire and a task completion assessment for its performance. The developed multipurpose customized orthotic device was found to provide an appropriate range of motion, ease in performing tasks, and took less time to complete tasks compared to previous works. The results indicated satisfactory performance, thereby improving quality of life. The multipurpose customized orthotic device successfully assisted the subjects with their daily activities, thus making them more independent in their rehabilitative period