Mesial temporal lobe epilepsy (MTLE) is the most common form of epilepsy, and the most medically intractable. An estimated one-quarter to one-half of the 400,000 patients in the United States with intractable epilepsy have MTLE. Generally, MTLE becomes intractable in adolescence and early adulthood. Persistence of seizures during this time commonly causes adverse social and psychological consequences which can become irreversible.