College Park, MD (August 23, 1999) -- For the first time, scientists believe they have discovered what happens in the brain just before an epileptic seizure. The research could "lead to new ways of treating the seizure that might be less drastic than the surgery that is now necessary for many patients," says Raima Larter, one of the scientists involved in epilepsy research at Indiana University Purdue University in Indianapolis (IUPUI). The study will appear in the September issue of the journal Chaos.
More than 2 million Americans live with epilepsy. More than half a million, including many children, don't respond to current treatment. When seizures persist, epilepsy is as debilitating a disorder as it was hundreds of years ago.
In the type of seizure studied by Larter and her colleagues, a small section of the brain that is behaving abnormally "recruits" normal brain tissue to behave abnormally as well. Patients with this type of seizure do not usually respond to medication, and many undergo brain surgery in an effort to control the disorder. Side effects of the surgery can include memory loss and speech impairment.
While scientists still don't know what triggers an epileptic seizure, it is commonly believed that seizures occur when there is a transition from the normal uncoordinated firing of neighboring nerve cells in the brain (neurons), to a periodic, common firing. Larter and her colleagues think they know what enables that critical transition, and theorize that it can be controlled.
The IUPUI researchers believe that the critical parameter is the speed at which neurons in healthy brain tissue communicate. They contend that when neurons are communicating at normal speed they fire unpredictably. But when the speed of communication increases, groups of neurons can quickly start firing in unison - which often leads to a full blown seizure.
One of the most important findings in this research, says neurosurgeon Robert Worth, is that "it explains why the seizures come and go." According to the study, normal brain tissue is only "recruited" to behave abnormally when neural communication in the otherwise healthy tissue speeds up. If the neuron communication speed could be adjusted (using drugs or electrical stimulation) just before the onset of a seizure, then the recruitment step could be "short-circuited", preventing the seizure.
That would mean that patients, whose only treatment option now is brain surgery, could choose a much less invasive way of controlling their epilepsy. And many others, without current options, might have the ability to live normal, healthy, seizure free lives.
Contacts:
Raima Larter
Indiana University Purdue University in Indianapolis
317-274-6882, larter@chem.iupui.edu
Robert Worth, M.D.
Neurosurgeon, IUPUI
317-274-8423, rworth@iupui.edu