Essential tremor poses one of the greatest therapeutic challenges to neurologists. This study will examine the effectiveness of the drug, levetiracetam or keppra, for the treatment of essential tremor.

Currently available pharmacological treatments for essential tremor are hampered by relatively low efficacy and intolerable side effects. Recent evidence indicates that levetiracetam (LEV) may modulate the dopaminergic system. In this regard LEV has been shown to reduce L-dopa-induced dyskinesias, tardive dyskinesia and myoclonus, and is relatively well-tolerated in the elderly. Previous studies examined the efficacy of LEV for the treatment of essential tremor. However, these were either open label or relatively short duration studies. A longer term study of LEV for the treatment of essential tremor is therefore warranted. In this randomized, double-blind, placebo-controlled crossover study, ten subjects with essential tremor will be randomly assigned to receive either LEV up to a maximum dose of 3000 milligrams (mg) per day or placebo. Study drug will be titrated up over 6 weeks and continued at 1500 mg twice daily for an additional 6 weeks. Following a 4 week washout period subjects will cross over to the other arm and continued for an additional 12 weeks. Subjects will be evaluated monthly by a blinded examining neurologist and research coordinator. At each study visit subjects will receive a neurological examination and will be evaluated using a 16-item scale for tremor and medication side effects. The data derived from study drug vs. placebo groups will be compared using the Mann-Whitney U and Wilcoxon W tests.

Inclusion Criteria:

• History of tremor for 5 or more years
• No other neurological problems

Exclusion Criteria:

• Prior stroke or other neurological disease, psychiatric problems
• History of renal disease
• Pregnancy