Effectiveness of Virtual Reality in Parkinson's Disease: Impact on Balance, Fall Risk, and Cardiorespiratory Exercise Capacity.

Neurological disorders are among the leading causes of disability worldwide, significantly affecting functional independence, mobility, and quality of life. Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by dopaminergic neuron loss in the substantia nigra, resulting in motor and non-motor symptoms that compromise multiple physiological systems. The main motor symptoms-bradykinesia, rigidity, resting tremor, and postural instability-directly impair balance and substantially increase the risk of falls. Additionally, individuals with PD often exhibit reduced cardiorespiratory fitness, which contributes to functional decline, decreased participation in daily activities, and increased caregiver burden.

Physiotherapy plays a crucial role in the comprehensive management of PD, targeting improvements in balance, mobility, motor function, and cardiorespiratory capacity to delay disability and promote autonomy. In recent years, emerging technologies have transformed conventional rehabilitation paradigms, with virtual reality (VR) gaining recognition as a promising tool for enhancing therapeutic outcomes.

Immersive VR systems provide controlled, interactive, and multisensory environments that facilitate repetitive, task-oriented motor practice with immediate sensory feedback. These features can increase motivation, engagement, and adherence to therapy, while simultaneously stimulating both motor and cognitive domains. Moreover, VR interventions may induce neuromodulation processes by activating and reorganizing neural circuits, thereby promoting neuroplasticity - a fundamental mechanism for functional recovery in neurodegenerative diseases such as PD.

Preliminary research suggests that VR-based rehabilitation can lead to measurable improvements in balance, reduction in fall risk, and enhancement of physical endurance. However, the current body of evidence remains limited by small sample sizes, heterogeneous methodologies, and a lack of direct comparisons with conventional physiotherapy. Gaps persist regarding which subgroups of PD patients benefit most, the medium- and long-term effects of VR interventions, and the neurophysiological mechanisms underlying these improvements.

This randomized controlled trial (RCT) aims to address these limitations by conducting a rigorous evaluation of an immersive VR intervention compared to standard physiotherapy in individuals with PD. A total of 50 participants will be randomly assigned (1:1) to either a VR group or a conventional physiotherapy group using the OxMaR (Oxford Minimization and Randomization) software, which employs adaptive minimization to balance baseline characteristics between groups.