Development of Anorectal and Core Activation Method with Wearable Cyborg HAL for Defecation Disorder Treatment

Defecation disorders in patients with neurological diseases significantly diminish their quality of life. The primary cause of this dysfunction is neurogenic dysmotility of the anorectum and the core muscles. Previous treatment programs targeting anorectal and core motility have yielded only temporary improvements or have been of limited clinical efficacy. In this study, we focused on cybernics treatment, where a wearable cyborg facilitates voluntary movement in paralyzed body parts, thereby the sensory feedback from paralyzed periphery induces neural plasticity. A distinctive feature of cybernics treatment is its potential for sustained clinical effects, even after the doffing the wearable device, suggesting ongoing improvement. We proposed a novel approach using this treatment modality for the anorectum and core muscles that could potentially restore defecation function permanently post-treatment. We developed a wearable system designed to enable voluntary core muscle actions based on the wearer's motor intentions. These intentions were detected by measuring bio-electrical signals (BES) from surface electrodes placed at the fusion site of the internal oblique and transversus abdominis (IO-TrA). We employed hip flexion while lying supine as the movement to activate the core muscles. The feasibility of this system was tested in an experiment involving three able-bodied participants. During the trials, we compared the time series of participants' hip joint angles and electrical activities in the core muscles while performing hip flexion using the developed system. The results showed that hip flexion was effectively synchronized with electrical activities in the core muscles across all participants, demonstrating the feasibility of the developed system for able-bodied wearers.