Inclusion criteria:

• Intractability: Two AEDs, one of which was either Dilantin, Tegretol, Carbatrol, or Trileptal used in appropriate doses, have failed due to inefficacy, not intolerance.
• Frequency and Duration: Persistence of disabling seizures at 6 per year or greater for less than two years after onset, or after recurrence if initial treatment resulted in seizure freedom for 6 or more months.
• Age: 12 years or older at baseline visit.
• History: Simple and complex partial seizures, with or without secondarily generalized seizures beginning in childhood or later, with or without febrile convulsions earlier.
• Absence of a history of serious cerebral insult after the age of 5; a progressive neurological disorder; mental retardation (I.Q. less than 70); psychogenic seizures; focal neurological deficits other than memory disturbances; unequivocal focal extratemporal EEG slowing or interictal spikes; or lesions on neuroimaging outside of the mesial temporal area.
• Seizure semiology: Auras that occur in isolation and are not primary sensory other than olfactory or gustatory. Absence of initial focal motor movements other than automatisms or dystonic posturing. Presence of postictal confusion.
• Neurological examination: No unexplained focal or lateralized neurological deficits other than memory dysfunction.
• Baseline QOL and ancillary outcome data:
• Adolescents - QOLIE-48-AD, CHQ, CBCL, PANAS, Life Events Scale, FAC, FEICS-PC completed.
• Adults - QOLIE-82/ESI55, locus of control, PANAS, Life Events Scale, FAD, FEICS-PC completed.
• Global rating scale completed.
• Baseline ancillary outcomes completed. Psychiatric evaluation: No evidence of psychosis, current or recent substance abuse, suicidality, anorexia, or psychogenic seizures. Baseline BSI and MINI or KSADS completed.
• Neuropsychological testing: I.Q. of greater than 70. No significant focal neurocognitive dysfunction inconsistent with MRI and PET findings. Baseline neuropsychological testing completed.
• Neuroimaging: Hippocampal atrophy on MRI T1 imaging with either increased ipsilateral mesial signal on T2 imaging, or ipsilateral hypometabolism on PET (Class I), or either hippocampal atrophy on MRI only, or temporal hypometabolism on PET only (Class II).
• Absence of temporal neocortical or extratemporal lesions on MRI, or diffuse unilateral or bilateral hypometabolism on PET.
• Video-EEG Monitoring:
• If neuroimaging is Class I, ictal EEG onset is lateralized to the ipsilateral side; if neuroimaging is Class II, ictal EEG onset is focal on the ipsilateral side.
• Absence of contralateral or extratemporal ictal onset.
• Absence of persistent extratemporal, or predominant contralateral focal interictal spikes or slowing, or generalized interictal spikes.
• Absence of psychogenic seizures.
• Seizure baseline: Seizure log, seizure report forms, and seizure severity scale completed.
• IAP: In those randomized to surgery only, contralateral hemisphere can support memory.