Soft Robotics for Post-Stroke Hand Rehabilitation: A Systematic Critical Review of Artificial Muscles and Finger Actuators

<title>Abstract</title> <p>Stroke remains a leading cause of long-term upper limb disability worldwide, with approximately 60% of survivors experiencing persistent hand impairment that severely compromises quality of life. Soft robotic technologies have emerged as promising alternatives to conventional rigid rehabilitation devices, offering enhanced safety, adaptability, and patient comfort. However, the rapid proliferation of diverse actuator designs has created confusion regarding their comparative performance, clinical readiness, and appropriate application contexts. This systematic critical review examines artificial muscle and finger actuator technologies for post-stroke hand rehabilitation, addressing the question: How do these technologies compare in terms of performance, portability, wearability, control sophistication, and clinical readiness? Analyzing 78 studies spanning McKibben muscles, bubble actuators, origami-inspired designs, fabric-based systems, pneumatic networks, and cable-driven mechanisms, we provide a novel taxonomy, comparative benchmarking framework, and clinical readiness assessment. Our critical synthesis reveals that while pneumatic actuators demonstrate superior force output (15–45 N) and range of motion, they suffer from critical portability limitations due to tethering requirements. Conversely, cable-driven systems offer greater portability but provide inferior force control and rehabilitation outcomes. Critically, only 23% of reviewed studies include stroke patient validation, and no standardized benchmarking protocols exist. We identify the current major research gaps, including the absence of long-term clinical trials, lack of integrated sensing, and insufficient home-based deployment solutions. This review provides researchers and clinicians with evidence-based guidance for technology selection and identifies priority directions for next-generation soft rehabilitation systems.</p>