CUSTOM-DBS: Current Steering to Optimize Deep Brain Stimulation

The study is a prospective, multi-center, double-blind, randomized controlled trial.

This study will compare various program settings for the bilateral stimulation of the STN
using the BSC implantable Vercise™ DBS System for the treatment of levodopa-responsive,
moderate to severe idiopathic PD.

Inclusion Criteria:

- Implanted bilaterally in STN with a Vercise DBS system for Parkinson's disease for at
least three months with programming optimized according to standard of care.

- UPDRS subset III score of ≥30 in the in the pre-operative meds off state.

- DBS must improve PD symptoms by ≥30% in the meds off state, as measured by UPDRS
subset III score.

- Medical and mental fitness to comply with programming visit and study related
procedures.

- Able to understand the study requirements and the treatment procedures and provides
written informed consent before any study-specific tests or procedures are performed.

- Off symptom rigidity score of ≥2 in the evaluated arm as determined by the UPDRS-III.

Exclusion Criteria:

- Have any significant medical condition that is likely to interfere with study
procedures or likely to confound evaluation of study endpoints, including any terminal
illness with survival <12 months.

- Resting and/or action tremor score of ≥3 on the evaluated side as determined by the
UPDRS-III in pre-operative meds off condition.