Brain pacemaker gets a software upgrade to fight freezing gait

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Participant has an implanted STN-DBS system with Boston Scientific Gevia™ or Genus™ R16 IPG connected to any brand lead or extension that have been approved by the FDA to be used with Gevia or Genus IPGs. 2. Participant is receiving treatment with carbidopa/levodopa, and/or with a dopamine agonist at the optimal doses as determined by a movement disorders neurologist. 3. DBS optimized with documented improvement in motor signs (UPDRSIII) from DBS Exclusion Criteria: 1. Participant is unable to understand the study requirements and the treatment procedures, or unwilling / unable to provide written informed consent before any study-specific tests or procedures are performed. 2. Participant is unwilling or unable to comply with visit schedule and study related procedures. 3. Participant's medication regimen has not been stable for at least 28 days prior to CG initiation. 4. Participant's DBS stimulation settings have not been stable for at least 28 days prior to CG initiation. 5. Participant is less than 21 years of age or older than 80 years of age. 6. Participant is a female who is breastfeeding or of child-bearing potential with a positive urine pregnancy test or not using adequate contraception as determined by the study investigator. 7. Participant has a terminal illness with life expectancy of \< 1 year. 8. Participant has history of recurrent or unprovoked seizures. 9. Participant currently diagnosed with drug or alcohol abuse, per DSM-5 criteria. 10. Participant is in a very advanced stage of Parkinson's disease defined as: (i) Stage 5 as classified by the Hoehn and Yahr scale on medication and DBS (non-ambulatory) or (ii) participant requires an assistive device to perform the TBC OFF-meds /ON-DBS at the time of enrollment. 11. Participant has a condition that makes walking difficult or could interfere with the study procedures or confound the evaluation of the study data, including musculoskeletal issues, peripheral neuropathies, hip/knee prostheses, or any visual or anatomical abnormality that affects their walking. 12. Participant has disabling dyskinesias. 13. Participant has a history of suicide attempt or current active suicidal ideation as determined by a positive response to Items 2-5 of suicide ideation sub-scale of the Columbia Suicide Severity Rating Scale (CSSRS). 14. Participant, at the time of enrollment, fails the subthalamic nucleus (STN) stimulation challenge test (subject must perceive distinct bilateral sensations). 15. Participant has less than 8% arrhythmicity as measured in the Turning and Barrier Course Figures of 8 (TBC-F8) pre-CG therapy (ON Medications/ON DBS /OFF CG).