When Epilepsy Drug Therapy Fails

New research tries to gauge who faces that fate

MONDAY, Jan. 27, 2003 (HealthDayNews) -- Although many people with epilepsy can keep their condition under control indefinitely with medication, for some the disease stops responding to drugs.

It has long been thought that those patients could be identified early in the course of their illness. But a new study appearing in the Jan. 28 issue of Neurology casts doubt on that assumption.

The study sought to determine how long it took before the disease would no longer respond to medication.

"We discovered it was not always evident at the beginning. That's the big surprise," says Anne Berg, lead author of the study, part of a large multi-center effort directed by Dr. Susan Spencer at Yale University School of Medicine.

"There appears to be a group of people who take a very long time before their seizures announce themselves as intractable," Berg adds. "If we learn to identify those patients early on, then perhaps we can understand the mechanisms involved."

This knowledge could lead to alternative therapies, including different types of drugs or even surgery, Berg says.

Epilepsy, sometimes called a seizure disorder, is a chronic medical condition produced by temporary changes in the electrical function of the brain, causing seizures that affect awareness, movement, or sensation, according to the Epilepsy Foundation.

Some 20 percent of adults with epilepsy end up with the intractable form of the disease. Most members of this subgroup have what is known as partial epilepsy, which affects only a localized region of the brain, the National Institutes of Health says.

In the study, Berg and her colleagues looked at 333 adults with partial epilepsy who had already undergone surgery to remove a piece of the brain's cortex, the source of the seizures, she says.

"When successful, surgery results in the complete elimination of seizures," Berg says. "Even if seizures are not completely eliminated, patients often have a substantial reduction in seizure frequency and, perhaps, severity."

The patients in the study went, on average, nine years from the onset of epilepsy to the point where their epilepsy no longer responded to medication.

One quarter (26 percent) of patients had experienced a remission period lasting at least one year before surgery; 8.5 percent reported an extended remission that lasted five or more years until surgery.

"A lot of these patients did very well and seemed to be home free," Berg says. "Based on their history, they might have been told, 'You're fine.' And, years later, their seizures come back."

Although it's not clear who will go on to have intractable epilepsy, there are some early clues.

Based on the results of this study, patients who were younger when their epilepsy started were more likely to go into remission and tended to have a longer period of time until their drugs became ineffective. "It's a clue but not yet an answer," Berg says.

The results "really support the need for trials to see if early intervention actually makes a difference in the course of the disease and also on quality of life, " says Margaret Jacobs, program director for epilepsy research at the National Institute of Neurological Disorders and Stroke.

Jacobs adds that there has been a shift in focus from just controlling seizures to really understanding the mechanisms at work.

"It shows you that patients should be treated aggressively right from the start and, if medications fail, the decision should be made to evaluate for epilepsy surgery," says Dr. Gregory Barkley, an epilepsy specialist with the Henry Ford Comprehensive Epilepsy Program in Detroit and a spokesman for the Epilepsy Foundation.

More information

For more on epilepsy and surgery for the condition, visit the Epilepsy Foundation, or the National Institute of Neurological Disorders and Stroke.

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