Clinical Outcomes of Deep Brain Stimulator (DBS) Electrodes Placed Using Intraoperative Computed Tomography (CT) and Frameless Stereotaxis

Background: Frame-based stereotaxis and microelectrode recording (MER) with mapping of
target structures has been the gold standard for deep brain stimulator (DBS) implantation.
Though supported by historical considerations, no Class I or II evidence exists that MER
adds significant value to the DBS implant procedure. With the advent of advanced magnetic
resonance imaging (MRI) and computed tomography (CT) imaging, particularly intra-operative
imaging, the argument for the continued use of MER during DBS implantation has been
substantially weakened. One rationale for pursuing CT-guided intraoperative imaging is due
to presumed increase in patient comfort with this method. DBS implantation with MER requires
that the patient remain awake during the entire procedure. , MER with frame-based
stereotaxis requires the patient to keep their head in a fixed position for a prolonged
period of time during which time they remain awake, causing significant patient discomfort.
Furthermore, Parkinson's disease patients must withhold their PD meds for a minimum of 12
hours prior to the procedure adding a sometimes significant degree of discomfort and anxiety
to the procedure.

Objective: The goal of this study is to compare the clinical outcomes of DBS electrodes
placed using intraoperative CT and frameless stereotaxis with those placed using MER and
frame-based stereotaxis.

Design: The proposed study will be a prospective non-interventional data collection study.

Setting and Subjects: Subjects for this study will be idiopathic Parkinson's disease
patients identified from the Oregon Health & Science University movement disorder clinic as
candidates for deep brain stimulation therapy. Enrollment will continue until fifty subjects
have been implanted with electrodes using frameless stereotaxis and intraoperative CT. Data
regarding quality of life, motor control, and amount of time during the day without levodopa
side effects will be collected pre-operatively and post-operatively. This data will be
compared to historical controls who have been implanted with DBS electrodes using MER and
frame-based stereotaxis. All surgical procedures will involve only Federal Drug
Administration (FDA) approved stereotactic equipment, used in the manner for which they have
been approved. All clinic procedures are standard of care for movement disorders patients in
the deep brain stimulation program.

Intervention: This study will be a non-interventional data collection study.

Measurements: Data regarding patient age, diagnosis, intracranial target, complications,
Unified Parkinson's Disease Rating Scale UPDRS Parts 3 (motor examination) and 4 (drug side
effects), Parkinson's Disease Quality of life PDQ-39, 3 day motor diary, 3 month falls
diary, neuropsychiatric evaluation and days in hospital following surgery will be collected.

Analysis: The patients will be examined prior to DBS placement both on and off dopaminergic
medications. They will then be examined 3 months and 6 months following DBS placement both
on and off drug with stimulator on after programming parameters have been optimized. The
following measures will be performed:

- Change in UPDRS Parts 3 and 4

- Change in PDQ-39

- Change in amount of time patient is experiencing Parkinson's disease symptoms and/or
side effects of treatment.

- Change in number of falls

- Change in neuropsychiatric evaluation, including:

- Beck Depression Inventory-II (BDI-II)

- Mattis Dementia Rating Scale-Second Edition (DRS-2)

- Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)

- Symptom Checklist-90-Revised (SCL-90-R)

- Wechsler Abbreviated Scale of Intelligence (WASI) We will also compare the number of
days spent in hospital following surgery. Adverse events related to the surgery will be
captured.

Inclusion Criteria:

- Idiopathic Parkinson's disease patients identified by OHSU movement disorders
neurologists as deep brain stimulation surgical candidates

Exclusion Criteria:

- Subjects who have already undergone implantation of DBS electrodes 2.Age < - - 18
years

- Surgical target site other than subthalamic nucleus or globus pallidus pars interna

- Subjects who choose to undergo MER and frame-based stereotaxis for the placement of
electrodes.

- Patients who will receive follow up neurology care and DBS programming at centers
other than OHSU.