# Effectiveness of High-Intensity Therapy in Rehabilitation of Parkinson's Disease Patients
## 1 Introduction  
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra, leading to motor impairments such as tremor, rigidity, bradykinesia, and postural instability [1]. Additionally, non-motor symptoms, including cognitive decline, depression, and autonomic dysfunction, significantly impact patients' quality of life [2, 3]. While pharmacological treatments, such as levodopa, provide symptomatic relief, they do not halt disease progression, necessitating complementary therapeutic approaches [4]. Recent advances in rehabilitation strategies emphasize the role of exercise therapy in mitigating PD symptoms by promoting neuroplasticity, improving motor function, and enhancing overall well-being [5, 6]. Among these interventions, high-intensity exercise protocols have garnered attention due to their potential to slow disease progression and improve motor performance [7, 8]. Technology offers new applications in training methods. Home-based training solutions (i.e., telerelabilization, sensory stimuli training, etc.) are nowadays easily accessible, providing flexible scheduling, individual tailoring, larger training volume, real-time feedback, and increased motivation [9]. In particular, state-of-the-art technologies, such asvirtual reality and brain-computer interfaces, enhance neuroplasticity [10]. During this process, the brain reorganizes itself by building new neural connections based on experience and learning. Different forms of virtual reality, including simple screen-based and fully immersive headset applications, offer new possibilities in rehabilitation, often along with real-time monitoring. In parallel, immersive virtual reality (VR) technologies are revolutionizing neurological rehabilitation by providing engaging, multisensory environments that enhance motor learning and motivation [11; 12]. VR-based interventions leverage interactive feedback, gamified exercises, and task-specific training to address motor deficits in patients with PD [13]. The integration of high-intensity VR-based agility training has demonstrated significant improvements in postural control, mobility, and cognitive-motor integration, making it a promising adjunct to traditional rehabilitation [14]. The IntegraPark Study and other recent trials have highlighted the feasibility and efficacy of VR-enhanced high-intensity exercise programs for patients with PD. These interventions, often employing rowing, cycling, and agility-based movements, provide task-specific training within immersive settings, promoting sustained engagement and neuroplastic adaptations [13]. By incorporating real-time feedback, adaptive difficulty levels, and cognitive challenges, VR-based rehabilitation fosters motor skill acquisition, balance retraining, and executive function improvement [15]. Despite promising findings, further research is warranted to establish optimal training protocols, long-term efficacy, and the neurophysiological mechanisms underlying high-intensity VR therapy in PD [16; 17]. The present study aims to evaluate the impact of a structured high-intensity VR training program on motor function, balance, aerobic capacity, and quality of life in patients with Parkinson's disease. By leveraging state-of-the-art VR exergames, motion tracking, and adaptive training paradigms, we seek to advance rehabilitation strategies for individuals affected by PD [18]. Exergames or exergaming refers to the activity of playing video games that involve physical exertion. It is an entertaining and motivating form of exercise, mostly targeting professional athletes, patients in rehabilitation after injuries or with neurology problems (i.e., stroke, Parkinson's, MS, etc. ), and the older adult population [19; 20; 21; 22]. The term is related to the terms gamification and serious gaming. Exergames are a special form of serious games, where intensive physical exercise is involved. Exergaming can also be performed in virtual reality environments [23; 24; 25].