We are carrying out this study to determine whether Keppra (a drug usually used to treat epilepsy) is an effective treatment for tremor in patients with Multiple Sclerosis. Tremor is one of the most common symptoms in MS, but also one of the most difficult to treat. A very small previous study has indicated that Keppra may be effective in this role, but we need to reproduce these results in many more patients before we can reliably confirm this.