Asymmetric Subthalamic Deep Brain Stimulation for Axial Motor Dysfunction in Parkinson's Disease

A Single-center, Randomized, Double-blinded, Double-crossover Trial of Asymmetric Subthalamic Deep Brain Stimulation for Axial Motor Dysfunction in Parkinson's Disease

This single-center, randomized, quadruple-blinded, double-crossover comparative efficacy trial will study the effects of unilateral 50% voltage reduction in axial motor dysfunction for patients with Parkinson's disease that develop treatment-resistant postural stability gait dysfunction after bilateral subthalamic nucleus deep brain stimulation surgery.

Inclusion Criteria:

• Patients with Parkinson's disease (PD) (previously diagnosed according to the UK brain bank criteria) who develop treatment-resistant postural instability gait dysfunction (PIGD) more than 6 months but less than 5 years after bilateral subthalamic nucleus deep brain stimulation (STN-DBS).
• Treatment-resistant PIGD will be defined as freezing of gait and UPDRS or MDS-UPDRS PIGD subscales of more than 6 points despite optimization of medications and bilateral STN-DBS programming.

Exclusion Criteria:

• Treatment-resistant PIGD less than 6 months or more than 5 years after STN-DBS surgery.
• PIGD responsive to optimization of medications and/or bilateral STN-DBS programming.
• Cognitive impairment or psychiatric comorbidities (including substance abuse) that would interfere with the informed consent process, study adherence or outcome assessments.
• Advanced PD or any other neurological, cardiovascular or musculoskeletal co-morbidities that would preclude or require assistance to complete the 10-meter walking test.
• Patients not able to comply with 4-week interval evaluations following their potential enrollment due to personal reasons.
• Serious illness (requiring systemic treatment and/or hospitalization) until subject either completes therapy or is clinically-stable on therapy, in the opinion of the site investigator, for at least 30 days prior to study entry.
• Inability or unwillingness of subject or legal guardian/representative to give written informed consent.