## 1 Introduction  
Strokes remain a leading cause of disability globally, profoundly affecting the quality of life of millions each year [1, 2]. Rehabilitation of post-stroke upper limb function is crucial [3, 4], as it directly affects patients' ability to perform daily activities and enhances individual autonomy [5, 6, 7]. Although traditional rehabilitation methods such as physical therapy and pharmacological interventions are effective, they typically require frequent visits to specialized centers. This can be costly and logistically challenging for many patients, particularly those who may require prolonged therapy [8, 9]. Spasticity is a common complication in patients with severe stroke that leads to pain and significant motor dysfunction. Treatment often involves long-term management strategies, including the use of botulinum toxin type A (BoNT-A), which has been widely adopted for its efficacy in reducing muscle hypertonicity and associated discomfort [8, 9, 10, 11, 12, 13]. However, botulinum therapy is repetitive and invasive, and when administered alone it may not improve upper limb function; it must be combined with occupational therapy [10]. Patients with chronic stroke are required to exercise at home to improve their upper limb function and require assistance from their family members [11]. This long-term, daily independent training may be physically and mentally demanding for patients and their families [12]. Recent advancements in noninvasive cerebral stimulation therapies such as repetitive transcranial magnetic stimulation (rTMS) combined with intensive upper limb training have shown promise in improving functions previously considered irreversible [4; 13; 14; 15; 16; 17]. Despite these advancements, the accessibility of innovative treatments in home settings remains limited, which poses a significant barrier to sustaining patient engagement and recovery. The integration of home-based training devices into standard post-stroke rehabilitation protocols could therefore represent a transformative approach to care, reducing the burden on healthcare systems, while simultaneously improving patient outcomes. Occupational therapists manually perform rehabilitation to treat upper limb dysfunction as an after-effect of stroke [18; 19], and the concept of user-dependent plasticity is particularly relevant in patients with chronic stroke [20; 21]. This suggests that the nervous system can functionally reorganize itself in response to the demands placed upon it, implying that consistent, repetitive use of the affected limbs can lead to improved motor function and recovery over time. Therefore, the development of home-based self-training devices, like the \"Kenko Yusuri\", is not only innovative but essential. These devices enable patients to engage in regular structured training at home without continuous professional supervision and align with the principles of use-dependent plasticity by facilitating frequent and repetitive use of the impaired limbs. This approach not only makes rehabilitation more accessible and cost-effective but also allows for therapy customization to meet individual needs, thereby enhancing the potential for recovery. These devices also ensure continuity of care, enabling patients to maintain and improve the long-term gains achieved in clinical settings. Additionally, the \"Kenko Yusuri\" shaking device is expected to offer therapeutic benefits in the management of spasticity. Its vibrational features are expected to relieve muscle tension, potentially complementing or reducing the need for invasive treatment. This could significantly enhance the quality of life and functional independence of stroke survivors by providing a nonpharmacological option for managing one of the most challenging complications of stroke recovery. Integrating home-based training devices into standard post-stroke rehabilitation protocols may represent a transformative approach to care; it may alleviate the burden on healthcare systems, while simultaneously improving patient outcomes.