Optical Fiber Force Myography Sensor for Fatigue Estimation in Functional Electrostimulation-induced Rehabilitation Systems

Current rehabilitation methodologies for individuals afflicted by stroke or spinal cord injury (SCI) involve intensive physical therapy. Combining functional electrical stimulation (FES) with mechanical assistance from exoskeletons and robotic gloves features a promising alternative to improve patients' recovery. However, current surface electromyography and force myography (FMG) approaches based on electronic transducers cannot assess fatigue during rehabilitation as the FES corrupts the acquired signals. Therefore, this work presents an optical fiber FMG sensor to evaluate muscular contraction by ensuring immunity to electromagnetic interference. Experiments conducted for upper and lower limbs reveal promising results, establishing a relationship between muscle contraction energy degradation and the duration of performed rehabilitation tasks.