Background and rationale

Parkinson’s disease (PD) is one of the most common neurodegenerative disorders, marked by the progressive degeneration of dopaminergic neurons in the substantia nigra and the resulting dopamine deficiency (1). PD is clinically characterized by the presence of bradykinesia in combination with either resting tremor, rigidity, or both, and is frequently accompanied by non-motor symptoms such as cognitive decline, depression, sleep disturbances, and autonomic dysfunction (2). Reduced motor function caused by dopaminergic deficits leads to impaired motor automaticity, which ultimately results in gait disturbances and adversely affects the quality of life in patients with PD (3). Although dopaminergic pharmacotherapy remains the gold standard of treatment, it offers only symptomatic relief and is associated with long-term complications such as levodopa-induced dyskinesia. Surgical interventions, including deep brain stimulation, provide benefit for selected individuals, yet most patients experience gradual functional deterioration despite therapy. The global prevalence of PD is rising significantly, mainly driven by population aging, increased disease duration (4–6). Therefore, there is a need for disease-modifying treatments and integrated rehabilitative strategies to preserve motor function, including gait, and to improve quality of life in patients with PD.

Robot-assisted training has recently emerged as a promising rehabilitation technology designed to deliver intensive, repetitive, and task-specific motor training to improve motor function, mobility, and gait restoration (7). One of the well-established pathophysiological goals of utilizing robot-assisted training to improve motor function is to promote neuroplasticity; therefore, it is widely used for diseases affecting the central nervous system, such as PD or stroke (7, 8). Robotic devices can assist or resist movements as needed, ensure consistent training intensity and dosage, and provide real-time feedback, thereby enhancing physical performance and motivation compared to conventional rehabilitation conducted by physical therapists (9). These benefits may arise from the ability to deliver high-repetition, task-specific, and precisely controlled interventions, reduce therapist burden, support patient engagement through individualized programming, and provide reliable, objective monitoring features that conventional therapy may lack due to variability in manual guidance and therapist workload. Traditionally, robots are primarily categorized into two types, exoskeletal and end-effector robots. However, several limitations restrict their broader adoption and clinical impact. Exoskeletal robots are often characterized by their weight, mechanical complexity, and high cost, which can make achieving a comfortable and precise fit challenging across diverse users (10). Misalignment between the axes of robotic joints and the wearer’s anatomical joints can induce unintended forces and torques, leading to discomfort, potential safety hazards, and even long-term injury with frequent use. Moreover, these devices generally lack portability due to their bulk and design complexity, restricting their practical application primarily to controlled, specialized clinical or research environments (11). End-effector robots, while generally simpler and safer regarding alignment, are limited in their ability to isolate control of individual joints and may lead to less natural movement patterns, offering insufficient support for patients with severe motor deficits (12).



* Funding
- The Korea Medical Device Development Fund grand funded by the Korea government (the Ministry of Science and ICT, the Ministry of Trade, Industry,
  and Energy, the Ministry of Health and Welfare, the Ministry of Food and Drug Safety) (RS-2022-00140621),
- The Chung-Ang University Research Scholarship Grants in 2025.
- The funder will have no role in any aspect of the study, including its design, data collection, analyses, interpretation, writing of the manuscript,
  or the decision to submit for publication.