Controlling Epilepsy : Surgical Cures, Pinpointing Epilepsy

by Food and Drug Administration (FDA)

(Page 3 of 3)

Surgical Cures

When all else fails, some people with epilepsy may benefit from surgical removal of the malfunctioning brain cells that spark their seizures. To benefit from such surgery, patients' seizures must begin in one fairly small area of the brain that is not responsible for speech, language, hearing, or other major faculties and that can be detected with an imaging technique.

Between a half to nearly three-quarters of patients with epilepsy who undergo such surgery are relieved of their seizures for at least five years, according to a recent consensus statement published by the National Institutes of Health. Some of these patients, however, may still require epilepsy medication to stay seizure-free. The surgery carries a less than 5 percent risk of death.

Occasionally, surgery is performed to sever the connections between the two halves of the brain to try to prevent the spread of abnormal discharges from one side of the brain to the other. Although this surgery doesn't entirely prevent seizures, it does appear to lessen their severity or frequency.

The decision to have surgery depends on the frequency, type and severity of seizures, possible brain damage or injury from frequent seizures, and the effect seizures have on quality of life, according to the NIH consensus statement. Drug therapy must be tried before surgery is considered.

Scientific knowledge about epilepsy has banished the demons and ancient stigmas surrounding the disease. Modern drugs, diet or surgery have made possible normal lives, free from frequent seizures, for most people with epilepsy.

Pinpointing Epilepsy

When diagnosing epilepsy, physicians first try to rule out short-term causes of seizures that may be treated directly. Tests of the patient's blood, urine, or cerebrospinal fluid, which bathes the brain, may reveal uncontrolled diabetes, poisoning, a kidney disorder, or an infection.

Doctors use the electroencephalograph to help diagnose epilepsy. This machine detects, via electrodes taped to the head, electrical charges that pass between the brain cells near the electrodes. These charges are recorded as a series of wavy lines (brain waves) in what is known as an electroencephalogram (EEG). If a person has a seizure during an EEG recording, the device may reveal special brain wave patterns that help the doctor decide whether a person has epilepsy and what type it is. Some forms of epilepsy are associated with specific EEG patterns that can be seen between seizures. An EEG recording session may last as little as 35 minutes or as long as 24 hours.

Some clinics have small TV cameras set up in the EEG test area to film the person's actions during the test. Review of the film together with the EEG results may give added clues to the kind of seizure occurring. Patients may also be given a portable EEG device that records their brain waves continuously for a day while they are in their normal environment.

To induce a seizure during an EEG recording, patients may be asked to breathe deeply during the session, limit their sleep the night before, or to fall asleep during the session. (Some types of seizures are more likely to occur with a lack of sleep, whereas others occur more often during sleep.) Patients may also be exposed to flashing lights or other images or sounds that can prompt a seizure. Electroencephalography is a painless, safe procedure.

A device similar to the EEG, called the magnetoencephalograph is being used experimentally. This device records the magnetic signals that accompany the electrical discharges of neurons. A recording from this device resembles that of an EEG, but an magnetoencephalograph can detect seizure activity from deeper in the brain than is possible with the standard EEG.

Sometimes computerized tomography (CT) and magnetic resonance imaging (MRI) are used to provide pictures of the brain that may reveal tumors, cysts, or excess fluid. If these conditions can be treated successfully, the seizures may stop.

CT scans and MRI images are also used to detect damaged areas or scars in the brain that may be sparking seizures. Such information determines the type of epilepsy a person has and guides therapy.

PET (positron emission tomography), which is being used experimentally, can also point to the origin of epilepsy by measuring sugar uptake. In the responsible brain region, sugar uptake increases during a seizure and falls below normal between seizures.

About the Author

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