Association of VAgus Nerve Stimulation and Treadmill Training for GAit Rehabilitation in DE Novo Parkinson's Disease

Gait speed (m/s) is measured using a 3D optoelectronic motion-capture system with inertial sensors during level walking on a 10-meter walkway with integrated force platforms. Standard lower-limb reflective markers and surface EMG are used to capture kinematic and muscle-activation patterns. Average gait speed is calculated as the mean forward velocity.

Spatiotemporal and kinematic gait parameters are measured using a 3D motion-capture system with inertial sensors and surface EMG while participants walk across a walkway with integrated force platforms. Parameters include stance and swing phase duration (s), single and double support time (s), step and stride length (cm) and variability (%), swing speed (m/s) and cadence (steps/min), lower-limb joint flexion-extension angles (°), peak vertical ground reaction force (N/kg), and muscle-activation timing (ms) from surface EMG. All listed parameters will be analyzed collectively as a single composite secondary outcome and will not be reported as separate outcome measures.

Motor function will be assessed using the Movement Disorder Society Unified Parkinson's Disease Rating Scale, Part III (MDS-UPDRS III), which evaluates bradykinesia, rigidity, tremor, posture, and gait-related motor signs. Total scores range from 0 to 132, with higher scores indicating worse motor impairment. Improvement is reflected by a decrease in the MDS-UPDRS III score.

Cognitive function is assessed using the Montreal Cognitive Assessment (MoCA), a validated screening tool designed to detect mild cognitive impairment. The MoCA evaluates multiple cognitive domains including attention, executive functions, memory, language, visuospatial abilities, abstraction, calculation, and orientation. Total scores range from 0 to 30, with higher scores indicating better cognitive performance.

Quality of life is assessed using the Parkinson's Disease Questionnaire-39 (PDQ-39), which measures mobility, activities of daily living, emotional well-being, stigma, social support, cognition, communication, and bodily discomfort. Domain and total scores range from 0 to 100, with higher scores indicating poorer quality of life. Improvement is reflected by a decrease in PDQ-39 scores.

Average gait speed (m/s) is measured using a 3D motion-capture system during level walking. This outcome represents the change in gait speed between the post-intervention visit (T1) and the follow-up visit (T2) to evaluate persistence of treatment effects.

Spatiotemporal and kinematic gait parameters (stance and swing duration (s), single and double support time (s), step and stride length (cm) and variability (%), swing speed (cm/s) and cadence (steps/min), joint flexion-extension angles (°), peak vertical ground reaction force (N/kg), and muscle-activation timing (ms)) are assessed with 3D motion capture, force platforms, and surface EMG. All listed parameters will be analyzed collectively as a single composite secondary outcome and will not be reported as separate outcome measures. This outcome reflects change in these parameters from T1 to T2.

Motor function will be assessed using the Movement Disorder Society Unified Parkinson's Disease Rating Scale, Part III (MDS-UPDRS III), which evaluates bradykinesia, rigidity, tremor, posture, and gait-related motor signs. Total scores range from 0 to 132, with higher scores indicating worse motor impairment. Improvement is reflected by a decrease in the MDS-UPDRS III score.

Cognitive function is assessed using the Montreal Cognitive Assessment (MoCA), a validated screening tool for the detection of mild cognitive impairment. The MoCA evaluates multiple cognitive domains including attention, executive functions, memory, language, visuospatial abilities, abstraction, calculation, and orientation. This outcome captures the change in MoCA total score from post-intervention (T1) to follow-up (T2) to evaluate the persistence of cognitive effects over time. Total scores range from 0 to 30, with higher scores indicating better cognitive performance.

Quality of life is assessed using the PDQ-39, which measures mobility, activities of daily living, emotional well-being, stigma, social support, cognition, communication, and bodily discomfort. This outcome represents the change in PDQ-39 total score from T1 to T2, where higher scores indicate poorer quality of life and improvement is reflected by a decrease in scores.

Serum and salivary levels of inflammatory cytokines (TNF-α, IL-1β, IL-13, IL-10, IL-6) will be measured using standardized ELISA or multiplex immunoassays. Concentrations will be expressed in pg/mL. Cytokines will be analyzed collectively as a composite inflammatory outcome.

Serum and salivary levels of α-synuclein will be measured using standardized immunoassays. Concentrations will be expressed in ng/mL.

Brain perfusion will be assessed using pseudo-continuous arterial spin labeling (PCASL). Imaging is performed at baseline (T0) and post-treatment (T1). Primary imaging endpoints include:

• Change in cerebral blood flow (CBF) in locomotor and motor-control regions (PCASL)

Functional connectivity will be assessed by functional MRI (fMRI). Imaging is performed at baseline (T0) and post-treatment (T1). The fMRI assessment includes a simulated gait task using a custom pedal system with synchronized visual feedback.

Primary imaging endpoints include:

• Change in functional connectivity within gait-related cortical-subcortical networks (fMRI).

Serum and salivary levels of inflammatory cytokines (TNF-α, IL-1β, IL-13, IL-10, IL-6) will be measured using standardized ELISA or multiplex immunoassays. Concentrations will be expressed in pg/mL. Cytokines will be analyzed collectively as a composite inflammatory outcome.

Serum and salivary levels of α-synuclein will be measured using standardized immunoassays. Concentrations will be expressed in ng/mL.