Comparative Effects of Virtual Reality and Proprioceptive Neuromuscular Facilitation in Patients With Parkinson's Disease

Effects of Virtual Reality and Proprioceptive Neuromuscular Facilitation on Upper Limb Sensorimotor Control Among Patients With Parkinson's Disease.

Parkinson's Disease is a chronic neurodegenerative disorder marked by the progressive loss of dopaminergic neurons in the substantia nigra and accumulation of α-synuclein (Lewy bodies).It impacts both motor and non-motor systems, with growing global prevalence-affecting 7-10 million people, mostly men over 60 years-due to increasing life expectancy and demographic shifts.

PD shows motor symptoms like tremors and bradykinesia, along with non-motor issues like depression, REM sleep disorder, and cognitive decline. Diagnosis is often delayed due to subtle early signs like constipation or shoulder pain and atypical cases lacking classical tremors.

VR offers immersive, task-specific therapy that enhances motor learning and neuroplasticity in a safe, engaging environment. By integrating sensory feedback and real-time motion tracking, VR reduces tremors, promotes cortical reorganization (notably in the sensorimotor cortex and cerebellum), and increases rehabilitation motivation through gamified experiences.

PNF is a hands-on therapy using tactile, auditory, and proprioceptive cues to improve coordination, strength, and movement patterns. Especially useful in Parkinson's rehabilitation, PNF targets rigidity, bradykinesia, tremors, and postural instability by reinforcing neuromuscular coordination and improving movement execution in functional, diagonal planes.

Sensorimotor control is the dynamic integration of sensory input, motor planning, and execution, which becomes disrupted in PD due to impaired proprioception and feedback loops. Patients rely excessively on visual feedback, making movement effortful, highlighting the need for focused upper limb rehabilitation strategies.

• Experimental: (VR+ RPT) Participants in this group received Virtual Reality (VR)-based training in addition to Routine Physical Therapy (RPT). The VR intervention was delivered using the Oculus Meta Quest 3 headset and consisted of immersive, goal-directed tasks performed three times per week for six weeks, each session lasting 30 minutes at a moderate intensity (RPE 11-13). VR tasks were designed to target specific motor impairments, including pick-and-place tasks for kinetic tremor reduction, tracing tasks to address bradykinesia, and reaching and grasping tasks to improve proprioception. Participants interacted with five virtual balls in a simulated environment, transferring them from one basket to another under therapist supervision. Alongside VR, participants also underwent Routine Physical Therapy (RPT) three times per week for six weeks, each 40-minute session consisting of a warm-up with diaphragmatic breathing, 30 minutes of stretching and strengthening for the core, hip, knee, back, and elbow extensors, and a cool-down with static stretches for major muscle groups.
• Control: (PNF+RPT) Participants in this group received Proprioceptive Neuromuscular Facilitation (PNF) therapy in addition to Routine Physical Therapy (RPT). PNF was administered three times per week for six weeks, with each session lasting 30 minutes at a moderate intensity (RPE 11-13). Specific PNF techniques were selected for symptom management: slow reversal for kinetic tremor to improve coordinated agonist-antagonist contractions, rhythmic initiation for bradykinesia to facilitate movement initiation, and tactile input to enhance proprioception and body awareness. PNF was administered under the direct guidance of a physical therapist, with manual contact and graded resistance tailored to individual capacity. Participants also received RPT on the same schedule and with the same structure as described for the experimental group, including warm-up breathing, targeted stretching and strengthening, and cool-down static stretches.

Inclusion Criteria:

1. Idiopathic Parkinson's Disease according to Gelb's criteria
2. Stage II-IV Hoehn &Yahr scale
3. Intact cognition status (MMSE > 24)
4. 50-80 years of age

Exclusion Criteria:

1. History of PD surgery
2. Phobia of virtual gaming systems
3. Visual anomalies
4. Cardiovascular problems
5. Severe dyskinesia or "on-off" fluctuations