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

• The primary objective of this trial is to evaluate and quantify neuronal coherence in basal ganglia structures at rest and during rewarded movement.
  

• The latency and amplitude of evoked activity related to decision-making processing. We will also measure the reaction times and the number of errors.
  

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 psychiatric and 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.