Lower-Limb Robotic Assistance Devices for Drop Foot: A Review

Abstract

Drop foot is a pathological type of gait frequently exhibited by individuals suffering from stroke and other neurological conditions due to the weakness of the ankle dorsiflexor muscles. To avoid common negative compensations, such as foot-slap during the loading response and toe-drag during the swing phase of gait, various drop foot assistive robotic devices and technologies have emerged over the last couple of decades. This review summarizes the design, working principle, and application of robotic devices for drop foot assistance and rehabilitation in the last decade. The research findings describe the design aspects of 72 lower-limb robotic assistance devices for drop foot, including 21 studies that evaluated specific design aspects through experimental trials. All the designs reviewed here demonstrated the capability to successfully improve drop foot impairments in the sagittal plane. Some leveraged advanced functional features to achieve optimal performance without jeopardizing the user’s natural range of motion, comfort, balance, or safety. However, there remain certain limitations when combining all these functional features into one robotic device. Overcoming these limitations should add great value to the future of advanced robotic devices for drop foot assistance and rehabilitation.