Stochastic Resonance Stimulation Effect on Gait Stability in Parkinson Disease

The Role of Sensory Deficits in the Neural Control of Balance During Walking in Parkinson's Disease

The present study explored the use of a technique called stochastic resonance (SR) stimulation that may help individuals with Parkinson Disease maintain balance while walking on challenging surfaces. Impaired balance represents one of the disease symptoms, putting people at risk for falls, partly due to impaired processing of sensory information. SR uses light electrical signals to improve the way the body detects sensations. We wanted to test if SR could help people with Parkinson disease stay steadier while walking. Each participant's optimal SR intensity was determined before they walked on a treadmill in a virtual environment that created visual disturbances to challenge their balance. We measured how much their body swayed, how they placed their feet, and how their ankles moved during the walking tasks.

Inclusion Criteria:

• Clinical diagnosis of Parkinson Disease
• Hoehn and Yahr (H&Y) stage ≤ III
• Can walk independently for at least 2 minutes without an assistive device or orthosis
• Ability to communicate discomfort during testing
• Can follow multi-step commands
• Scored at least 24/30 on the Montreal Cognitive assessment (MoCA)

Exclusion Criteria:

• Any head, neck, or face injury in the six months prior to the study (e.g., concussion, eye injury)
• History of vestibular or ocular dysfunction
• Currently taking any medications affecting balance (i.e. antibiotics)
• Injuries to lower extremities affecting balance in the past six months
• Pregnancy
• Any neurological disorders other than Parkinson's disease (e.g., seizure disorders, closed head injuries with loss of consciousness greater than 15 minutes, CNS neoplasm, history of stroke)
• Unstable cardiac or pulmonary disease
• Clinically obese (BMI 30 or above)
• Any metal implant in the feet or legs that is close to the stimulating electrodes
• A known allergy to medical-grade adhesives
• Any other comorbidity affecting the ability to safely walk without assistance for at least 2 minutes
• Exhibited severe dyskinesia
• Did not respond to L-DOPA or other dopaminergic treatment
• Exhibited cardiovascular-autonomic or multiple-system symptoms indicative of a "Parkinsonism-plus" presentation