Analysis of Visual-Motor Task Electrophysiological Activity During Deep Brain Stimulation for Treatment-Resistant Movement Disorders

Objective:

The objective of this pilot study is to characterize the abnormal neuronal firing patterns
of basal ganglia and thalamic neurons and those in the premotor cortex in patients with
treatment-resistant movement disorders undergoing deep brain stimulation (DBS) surgery.
Neuronal activity will be studied in a decision-making task guided by reward. Secondary
objectives will involve study of how activity in the brain is modulated in such a task and
how DBS can influence the cerebral activity related to decision-making.

Study population:

Fifteen adult patients with treatment-resistant movement disorders (Essential tremor or
Parkinson s disease) who are undergoing deep brain stimulation surgery at Suburban Hospital,
Bethesda, Maryland, will be studied.

Design:

This is a physiology study of medically refractory patients who have been scheduled for
implantation of a deep brain stimulation device into basal ganglia or thalamic structures.
Prior to surgery, patients will learn a rewarded visual-motor task and undergo
magnetoencephalography (MEG). The task will be repeated during DBS surgery, with collection
of information on electrical activity including single neuronal unit and local field
potentials. The task and MEG will be repeated 3 and 6 months after surgery.

Outcome measures:

The collected data will be analyzed for coherence patterns during rest and rewarded
movements. We plan to characterize and quantify the oscillatory activity present in motor
circuits of patients during rewarded visually guided movements. We hypothesize that during
visually guided movements, neuronal coherence will be significantly increased relative to
resting periods. Activity during surgery will be compared with MEG recordings in the same
task both before and after surgery. By understanding the alteration in oscillatory patterns
in these patients, we hope to improve DBS stimulation paradigms in order to optimize
treatment protocols.

- INCLUSION CRITERIA:

Adult patients (over 18 years of age) with severe treatment-resistant ET or PD who are
scheduled for deep brain stimulation surgery at Suburban Hospital

Able to provide Informed Consent

EXCLUSION CRITERIA:

Subjects who are not willing or able to safely tolerate the study procedures

Subjects who have untreated depression or psychiatric disorder

Subjects who use illicit substances

Subjects who are pregnant

Subjects who are claustrophobic

Subjects who have metallic dental fillings.

Subjects who have any of the following: cardiac pacemaker; implanted cardiac
defibrillator; aneurysm clip; neuro or bone stimulator; insulin or infusion pump;
implanted drug infusion device; cochlear, otologic, or ear implant; prostate radiation
seeds; IUD (intrauterine device); transdermal medication patch (Nitro); any type of
prosthesis (eye, penile); heart valve prosthesis; shunt (spinal/intraventricular); wire
sutures or surgical staples; bone/joint pin, screw, nail, plate; body tattoos or makeup
(eyeliner/lip); body piercing(s) (non-removable); breast tissue expander; any metallic
implants or objects.