This study involves patients who are already planning to have deep brain stimulation (DBS) surgery to treat the symptoms of severe Parkinson's Disease (PD). The study has two goals:

1. to evaluate the effectiveness of implanting DBS electrodes in the two most common locations for DBS (subthalamic nucleus (STN), and globus pallidus interna (GPi)), instead of just one electrode, on each side of the brain; and
2. to develop an adaptive DBS system using brain signals measured from these two electrodes.

The purpose of this study is a small, first in man, clinical feasibility trial for patients with severe Parkinson's Disease (PD), who are already clinically eligible for deep brain stimulation (DBS) with two goals:

1. to compare efficacy from two common sites of DBS (subthalamic nucleus (STN), and globus pallidus interna (GPi)) through the implantation of dual DBS electrodes on each side of the brain; and
2. to develop a closed loop DBS system using evoked and spontaneous potentials derived from these two electrodes.

The study will involve bilateral dual DBS electrode placement in clinically standard locations (ie, STN and GPi) unilaterally or (more often) bilaterally, the placement of the RC+S Medtronic research implantable pulse generator (IPG), and a commitment to return for both extensive postoperative programming and testing to define clinical efficacy and separate research days to develop the closed loop approach. In addition, patients will undergo intraoperative research using temporary percutaneous extensions to the DBS electrode(s) and DBS lead cannula after implantation to confirm the electrode location and to identify what the signals will look like during later chronic recordings through the research IPG.

The research RC+S IPG includes both ordinary DBS stimulation as well as a recording system that simultaneously measures the DBS local evoked potential (DLEP) and/or local field potential (LFP) responses from either the same or a second DBS electrode.

In a separate cohort, we are enrolling healthy volunteers as blinded raters of audio recordings made by people with Parkinson's disease and without Parkinson's disease to study whether different features of speech patterns are specific to PD and whether there are measurable differences in these speech features when PD participants are on different deep brain stimulation settings. These ratings do not contribute to the primary or secondary endpoints of this study.

Study design details listed in this record are specific to the Implanted RC+S clinical trial cohort.

Implanted RC+S arm Inclusion / Exclusion Criteria:

Inclusion Criteria:

• able to give informed consent
• diagnosed with Parkinson's Disease and is considered a surgical candidate for DBS
• has medication-related side effects from levodopa (i.e., dyskinesias, on-off fluctuations)
• has off-on improvement with levodopa of at least 30%
• is available for follow-up visits for length of study

Exclusion Criteria:

• is not safe surgical candidate for DBS
• has severe neurological injury or disease other than Parkinson's Disease
• has condition requiring repeated MRI scans
• has untreated, clinically significant depression
• has an electrical or electromagnetic implant
• had a prior thalamotomy or surgical ablation procedure
• has dementia interfering with ability to comply with study requirements or give informed consent
• abuses drugs or alcohol
• has a history of seizures
• has any metallic implants
• is pregnant

Speech Rater Inclusion / Exclusion Criteria:

Inclusion Criteria:

• able to give informed consent
• has no hearing impairment (by self-report)
• is a native English speaker

Exclusion Criteria:

• is a speech therapist or clinician in a related field
• studies linguistics / logopedics

IPD to be shared: IPD for all participants that support the primary and secondary outcome measures listed in clinicaltrials.gov, after deidentification.

Data are available now through the end of funding (estimated January 2027). Additional data are updated on an annual basis.

Supporting Information (informed consent form) is available on clinicaltrials.gov.

IPD are available by request at the Data Archive for the BRAIN Initiative (dabi.loni.usc.edu). Requests for access will be evaluated through the end of grant funding (estimated January 2027).