The goal of this clinical trial is to learn if adaptive deep brain stimulation (DBS) can decrease or prevent freezing of gait in participants with Parkinson's disease.

The main questions it aims to answer are:

1. Does adaptive DBS lead to fewer freezing of gait episodes for participants compared to their clinical continuous DBS settings?
2. Does adaptive DBS change other parts of participants' walking, like step length, step time, or step symmetry?

Investigators will compare personalized adaptive DBS settings for each participant with their continuous DBS settings to see if adaptive DBS works better to treat gait symptoms, including freezing of gait.

Participants will have DBS insertion surgery as part of their standard medical care. Along with the DBS system, they will also have permanent sensors placed between their skull and scalp to detect brain activity related to movement. After, participants will:

1. Measure their walking using at-home monitoring devices (worn on the hip or ankles) while on their clinical continuous DBS settings.
2. Visit the lab for check-ins and testing of adaptive DBS settings.
3. Try different adaptive DBS settings at home, while wearing at-home monitoring devices.

Inclusion Criteria:

1. Ability to give informed consent for the study

2. Movement disorder symptoms that are sufficiently severe, in spite of best medical therapy, to warrant surgical implantation of deep brain stimulators according to standard clinical criteria

3. Patient has requested surgical intervention with deep brain stimulation for their disorder

4. No magnetic resonance (MR) abnormalities that suggest an alternative diagnosis or contraindicate surgery

5. Absence of significant cognitive impairment (score of 21 or greater on the Montreal Cognitive Assessment (MoCA)),

6. Signed informed consent

7. Ability to comply with study follow-up visits for brain recording, testing of adaptive stimulation, and clinical assessment.

8. Age 21-75

9. Diagnosis of idiopathic PD with duration of motor symptoms for 3 years or greater

10. Patient has undergone appropriate therapy with oral medications with inadequate relief as determined by a movement disorders neurologist.

11. UPDRS-III score off medication between 20 and 80 and an improvement of at least 30% in the baseline UPDRS-III on medication score, compared to the baseline off-medication score, and motor fluctuations with at least 2 hours per day of on time without dyskinesia or with non-bothersome dyskinesia.

    OR Patients with tremor-dominant PD (a tremor score of at least 2 on a UPDRS-III sub-score for tremor), treatment resistant, with significant functional disability despite maximal medical management

12. Patients with gait impairments including freezing of gait off medication.

13. Ability of patient and/or caregivers to recharge the system evaluated by all clinicians and study personnel.

Exclusion Criteria:

1. Coagulopathy, anticoagulant medications, uncontrolled hypertension, history of seizures, heart disease, or other medical conditions considered to place the patient at elevated risk for surgical complications
2. Evidence of a psychogenic movement disorder: Motor symptoms that remit with suggestion or "while unobserved", symptoms that are inconsistent over time or incongruent with clinical condition, plus other manifestation such as "false" signs, multiple somatizations, or obvious psychiatric disturbance.
3. Pregnancy: all women of child bearing potential will have a negative urine pregnancy test prior to undergoing their surgical procedure.
4. Significant untreated depression (BDI-II score >20). History of suicidal attempt or active suicidal ideation (Yes to #2-5 on C-SSRS)
5. Any personality or mood symptoms that study personnel believe will interfere with study requirements.
6. Subjects who require Electroconvulsive therapy (ECT), Repetitive Transcranial Magnetic Stimulation (rTMS) or diathermy
7. Implanted stimulation systems such as cochlear implant, pacemaker, defibrillator, or neurostimulator
8. Previous cranial surgery
9. Drug or alcohol abuse
10. Meets criteria for Parkinson's disease with mild cognitive impairment (PD-MCI). These criteria are performance of more than two standard deviations below appropriate norms, for tests from two or more of these five cognitive domains: attention, executive function, language, memory, and visuospatial tests.
11. Known allergies to the implantable device components including titanium, polyurethane, silicone, and nylon.