Design, control and medical effects of hand support exoskeletons: A survey of recent works

Hand exoskeletons have emerged over the past two decades as promising tools to restore or augment hand function in individuals with neurological injury and to support users in daily activities. This paper presents a comprehensive survey of recent developments in wearable hand exoskeletons. First, key design considerations of hand exoskeletons are investigated, including primary design parameters, actuation and power transmission schemes, and factors related to safety and fit. From a perspective of device control, existing strategies are reviewed according to rehabilitation stages, controller characteristics and feature quantities. Then, functional and clinical evidence was interpreted as engineering or mechanistic validation, functional assistive evidence, or clinically relevant outcomes. Clinically relevant outcomes showed the highest favourable proportion (83%, 19/23 domain-level observations), followed by functional assistive evidence (79%, 22/28) and engineering or mechanistic validation (73%, 11/15), suggesting a broadly positive direction of evidence. Current studies most consistently support short-term functional assistance and task-capacity enhancement, whereas training-related clinical benefits remain promising but limited by small samples, heterogeneous populations and devices, variable training dose, co-interventions, and limited follow-up. The design-control-outcome synthesis suggests that lightweight, low-impedance, well-aligned, and safe architectures, together with intention-aware or adaptive control, may improve usability, engagement, and personalisation, although their independent clinical contribution remains insufficiently isolated. Finally, existing problems of hand exoskeletons are discussed, and potential directions for future research are outlined.