Surgery as a Treatment for Medically Intractable Epilepsy

• Percentage seizure-free
• Mean Engel Class one year after surgery
• Percentage with permanent neurological side-effects from surgical treatment
• Incidence of serious complications of epileptic seizures

Background:

- Medically intractable epilepsy is the term used to describe epilepsy that cannot be controlled by medication. Many people whose seizures do not respond to medication will respond to surgical treatment, relieving seizures completely or almost completely in one-half to two-thirds of patients who qualify for surgery. The tests and surgery performed as part of this treatment are not experimental, but researchers are interested in training more neurologists and neurosurgeons in epilepsy surgery and care in order to better understand epilepsy and its treatment.

Objectives:

- To use surgery as a treatment for medically intractable epilepsy in children and adults.

Eligibility:

- Children and adults at least 8 years of age who have simple or complex partial seizures (seizures that come from one area of the brain) that have not responded to medication, and who are willing to have brain surgery to treat their medically intractable epilepsy.

Design:

• Participants will be screened with a medical history, physical examination, and neurological examination. Imaging studies, including magnetic resonance imaging and computer-assisted tomography (CT), may also be conducted as part of the screening. Participants who do not need surgery or whose epilepsy cannot be treated surgically will follow up with a primary care physician or neurologist and will not need to return to the National Institutes of Health for this study.
• Prior to the surgery, participants will have the following procedures to provide information on the correct surgical approach.
• Video electroencephalography monitoring to measure brain activity during normal activities within a 24-hour period. Three to four 15-minute breaks are allowed within this period.
• Wada test to evaluate speech, comprehension, and memory centers of the brain, using a contrast dye to study the blood vessels of the brain and a short-term anesthetic administration procedure to test the effects on areas of speech and memory.
• Depth electrodes and/or brain surface electrodes to measure brain activities and determine the part of the brain that is responsible for the seizures (seizure focus).
• Participants will have a surgical procedure at the site of their seizure focus. Brain lesions, abnormal blood vessels, tumors, infections, or other areas of brain abnormality will be either removed or treated in a way that will stop or help prevent the spread of seizures without affecting irreplaceable brain functions, such as the ability to speak, understand, move, feel, or see.
• Participants will return for outpatient visits and brain imaging studies 2 months, 1 year, and 2 years after surgery.

Objective

This protocol is being performed to study the normal human biology and disease pathogenesis (natural history) in patients with medically intractable epilepsy, 2) provide standard surgical treatment of medically intractable epilepsy, 3) follow the course of patients after epilepsy surgery, and 4) to investigate neurophysiological correlates of human cognitive processes such as memory, learning, attention, language, perception, and action. Neurophysiologic recordings will be compared with those in the resting awake state and during sleep.. Any treatment under this protocol will be based on the current standard of care for epilepsy surgery.

Study Population

Patients 8 years and older whose seizures are uncontrollable with medication may participate in this study.

Study Design

Patients will be screened by study neurologists to confirm their diagnosis of medically intractable epilepsy. Patients that do not have a confirmed diagnosis of medically intractable epilepsy will be offered further evaluation in protocol 01-N-0139, Evaluation and Treatment of Patients with Epilepsy. Patients confirmed to have medically intractable epilepsy will be offered standard invasive and non-invasive diagnostic and surgical procedures. Diagnostic invasive monitoring with intracranial electrodes for further localization of their seizure focus may be required. The ultimate goal is to surgically remove or modify the epileptic focus. Standard procedures to be performed are 1) anterior temporal lobectomy or 2) amygdalohippocampectomy for temporal lobe epilepsy, 3) focal cortical resection for epilepsy that arises outside the temporal lobe, 4) removal of brain lesions causing epilepsy, and 5) multiple subpial transection.

In patients in whom invasive monitoring is medically necessary, neurophysiologic activity during cognitive tasks will be captured from intracranial surface and depth electrodes. Analysis will focus on the role of neuronal firing and aggregate neural activity 1) during cognitive function, 2) in other states such as wakefulness and sleep, and 3) during periods of time surrounding seizure activity.

Patients will be followed for two years after the surgical procedure and will receive standard neurological examinations and MRI evaluation of the brain. Participants in this protocol will be evaluated for potential eligibility for other NINDS clinical trials.

Outcome Measures

The primary outcome measure is the change in seizure frequency, as measured by the Engel scale before and 1 year after treatment. Secondary outcome measures include 1) percentage of patients who are able to be completely withdrawn from anti-epileptic medication; 2) percentage of patients who are seizure-free (Engel Class I); 3) mean Engel Class one year after surgery stratified by the type of surgical procedure; 4) percentage of patients with permanent neurological side-effects from surgical treatment; 5) incidence of serious complications of epileptic seizures, and 6) neurophysiological correlates of cognitive function.

• Epilepsy
• Epilepsy, Temporal Lobe
• Partial Epilepsy

• Sperling MR, Feldman H, Kinman J, Liporace JD, O'Connor MJ. Seizure control and mortality in epilepsy. Ann Neurol. 1999 Jul;46(1):45-50.
• Jobst BC, Siegel AM, Thadani VM, Roberts DW, Rhodes HC, Williamson PD. Intractable seizures of frontal lobe origin: clinical characteristics, localizing signs, and results of surgery. Epilepsia. 2000 Sep;41(9):1139-52.
• Mosewich RK, So EL, O'Brien TJ, Cascino GD, Sharbrough FW, Marsh WR, Meyer FB, Jack CR, O'Brien PC. Factors predictive of the outcome of frontal lobe epilepsy surgery. Epilepsia. 2000 Jul;41(7):843-9.

• INCLUSION CRITERIA:

To be eligible for entry into the study, candidates must meet all the following criteria:

1. Be 8 years of age or older.
2. Have simple or complex partial seizures.
3. Seizures must persist despite medical therapy (medically intractable epilepsy).
4. Able to give informed consent, or have a parent able to provide informed consent if a child.
5. Agree to undergo brain surgery if indicated to treat medically intractable epilepsy.

EXCLUSION CRITERIA:

Candidates will be excluded if they:

1. Are pregnant (women of childbearing age will be tested with a urine pregnancy test and will have agreed to avoid being pregnant by practicing a reliable form of contraception or by abstinence from sexual intercourse while undergoing evaluation for epilepsy surgery and for 1 month after epilepsy surgery).
2. Cannot have an MRI scan.
3. Have a bleeding disorder that cannot be corrected before invasive testing or surgery, or other medical conditions which would make testing or surgery unsafe, such as lung or cardiac disease which would increase the risk of general anesthesia or severe immunodeficiency or systemic cancer not related to a brain lesion.