Development of Supine-Use Wearable Cyborg for Treatment of Neurogenic Bowel Dysfunction after Spinal Cord Injury

Neurogenic bowel dysfunction (NBD) is a common issue among patients with spinal cord injury (SCI), significantly affecting their quality of life. The primary cause of NBD is weakened deep core muscular function and colonic dysmotility. We hypothesized that cyborg-assisted core exercise has the potential to restore deep core muscular function by the proprioceptive feedback, at the same time, the vasovagal response induced by the intra-abdominal pressure increase could restore colonic dysmotility simultaneously. Wearable cyborgs have traditionally been developed for use in standing or seated positions, which makes it difficult to apply to most SCI patients who cannot maintain such posture. The purpose of this study is to develop a supine-use wearable cyborg that assists in a core exercise based on the wearer's motor intention and to confirm its basic performance. We developed a wearable cyborg that interprets bio-electrical signals (BES) measured from the lower abdomen as motor intention toward deep core muscles and converts them into hip flexion torque via a hip joint motor. This mechanism enables the voluntary contraction of deep core muscles through contraction of hip flexor connected with the muscles. After verifying its safety in healthy individuals, we conducted an experiment for a patient with chronic SCI. As a result, our device generated hip flexion torque synchronized with BES, enabling intention-based deep core contraction. After the cyborg-assisted exercise, a power of the electroenterogram significantly increased. Additionally, stool consistency improved after seven days of repeated exercise, implying enhanced intestinal activity. These results confirm the basic performance of our device and the potential to eliminate NBD.