Specific Aims:~To compare the therapeutic window (TW) of directional versus nondirectional deep brain stimulation for treatment of tremor.~Hypothesis: directional DBS will result in a wider TW than nondirectional DBS.~To compare the effects of directional versus nondirectional DBS on speech Hypothesis: Objective and subjective speech impairment will occur to a greater extent in nondirectional DBS versus directional DBS optimized for tremor control.~To compare the effects of directional versus nondirectional DBS on balance and gait Hypothesis: Objective and subjective balance and gait impairment will occur to a greater extent in nondirectional DBS versus directional DBS optimized for tremor control.~To assess efficacy for tremor of nondirectional and directional DBS in an optimized programming configuration Hypothesis: both directional and nondirectional DBS will significantly improve tremor compared to baseline.
This will be a single center (OHSU) proof of concept trial to demonstrate that directional deep brain stimulation (DBS) creates a larger therapeutic window for the treatment of essential tremor (ET), effectively treats ET, and minimizes effects on speech, gait and balance compared to nondirectional DBS.