 Subjects with epilepsy must currently be taking an AED which exerts its primary method of action on a system other than GABA. Examples include sodium or calcium channel blockers phenytoin, carbamazepine, oxcarbazepine, lamotrigine, zonisamide, and ethosuximide, drugs that bind to SV2A sites levetiracetam, or drugs which bind to the alpha2delta subunit of calcium channels gabapentin and pregbalin. Patients on AEDs that have direct effects on GABA and glutamate vigabatrin, phenobarbital, benzodiazepines, tiagabine will be excluded. No subject s medication will be changed for the purpose of inclusion in this study. 