Neural Signatures of Parkinson's Disease

Recruitment & Eligibility

Inclusion Criteria

a diagnosis of idiopathic Parkinson's disease, with bilateral symptoms at Hoehn and Yahr Stage greater than or equal to II.
Documented improvement in motor signs on versus off dopaminergic medication, with a change in the Unified Parkinson's Disease Rating Scale motor (UPDRS III) score of >= 30% off to on medication.
The presence of complications of medication such as wearing off signs, fluctuating responses and/or dyskinesias, and/or medication refractory tremor, and/or impairment in the quality of life on or off medication due to these factors.
Subjects should be on stable doses of medications, which should remain unchanged until the DBS system is activated. After the DBS system is optimized (during which time the overall medication dose may be reduced to avoid discomfort and complications such as dyskinesias) the medication dose should remain unchanged, if possible, for the duration of the study.
Treatment with carbidopa/levodopa, and with a dopamine agonist at the maximal tolerated doses as determined by a movement disorders neurologist.
Ability and willingness to return for study visits, at the initial programming and after three, six and twelve months of DBS.
Age > 18

Exclusion Criteria

Subjects with significant cognitive impairment and/or dementia as determined by a standardized neuropsychological battery.
Subjects with clinically active depression, defined according to the Diagnostic and Statistical manual of Mental Disorders, Fourth Edition (DSM-IV) criteria and as scored on a validated depression assessment scale.
Subjects with very advanced Parkinson's disease, Hoehn and Yahr stage 5 on medication (non-ambulatory).
Age > 80.
Subjects with an implanted electronic device such as a neurostimulator, cardiac pacemaker/defibrillator or medication pump.
Subjects, who are pregnant, are capable of becoming pregnant, or who are breast feeding.
Patients with cortical atrophy out of proportion to age or focal brain lesions that could indicate a non-idiopathic movement disorder as determined by MRI
Subjects having a major comorbidity increasing the risk of surgery (prior stroke, severe hypertension, severe diabetes, or need for chronic anticoagulation other than aspirin).
Subjects having any prior intracranial surgery.
Subjects with a history of seizures.
Subjects, who are immunocompromised.
Subjects with an active infection.
Subjects, who require diathermy, electroconvulsive therapy (ECT), or transcranial magnetic stimulation (TMS) to treat a chronic condition.
Subjects, who have an inability to comply with study follow-up visits.
Subjects, who are unable to understand or sign the informed consent

Study & Design

Arm && Interventions

Group	Intervention	Description
Activa PC+S	Activa PC+S	-

Primary Outcome Measures

Name	Time	Method
Change in Resting State Beta Band Power Over Time	Baseline and 1 Year	We compared the beta band (13-30 Hz) power in the neural signal at the initial programming visit (baseline) and at the 12 month follow-up visit (1 year) after turning off deep brain stimulation therapy. Beta band power is normalized to average beta band power at the initial programming visit. Using a linear mixed model for repeated measures over time, regression beta coefficient was obtained to determine if beta power changed significantly between the initial programming and the 12 month follow-up visit.
Sample Beta Entropy	1 day	Sample entropy is a measure of estimated conditional predictability, calculated within a frequency range of a patient's local field potential. Freezers are subjects who have clinical history of freezing of gait symptoms and/or if the subject displayed freezing behavior pre-operatively or during the in-study gait tasks relative to non-freezers, those who have never experienced freezing of gait. We measured sample beta (13-30 Hz) entropy in subjects' local field potential. Higher values of sample entropy indicate lower estimated conditional predictability. Testing occurred over one day, at a range of approximately 1 month to 7 months post DBS device implantation.

Secondary Outcome Measures

Name	Time	Method

Recruitment & Eligibility