A Novel Bilateral Upper Limb Training Method for Stroke Rehabilitation

Post-stroke individuals often experience upper limb sensorimotor impairments that limit their ability to perform activities of daily living (ADLs). Bilateral upper limb training (BULT) is essential in stroke rehabilitation, as many ADL tasks require bilateral coordination and benefit from enhanced interhemispheric coordination demands—the key aim of the method presented here. However, evidence supporting the superiority of BULT over unilateral upper limb training (UULT) is limited due to the complexity and limited accessibility of BULT devices in experimental and clinical settings. The low sensitivity of conventional motor function tests is also a serious obstacle to detecting subtle differences in bilateral upper limb skill levels. This paper introduces a novel, tablet-based BULT approach using a tetherball circling task within a simple non-immersive virtual reality (VR) application, incorporating wearable inertial sensors (ISs) on the wrists. In this study, 18 stroke patients and 18 healthy controls were asked to rhythmically tilt the tablet with both hands to rotate a virtual tetherball along a circular guideline. Task performance and forearm end-effector kinematics were analyzed using different parameters. Repeated measures ANOVA resulted in significant differences in task performance, asymmetry, and coordination characteristics. The findings indicate that the proposed BULT method is both effective for rehabilitation and sensitive to assess the subtle differences in bilateral upper limb skill levels. With its high accessibility and user-friendliness, the proposed method can support future BULT research and stroke rehabilitation.