Aura origins show the way in epilepsy surgery
By Nathan Seppa
Epileptic seizures are often preceded by auras, which patients experience in many ways: visual disturbances, butterflies in the stomach, or even déjà vu. An aura can reveal which part of the brain is spawning a seizure, but multiple auras in a person have heretofore offered little guidance to doctors.
A new study finds, however, that multiple auras tend to originate in the right hemisphere of the brain, often from an identifiable starting point. Pinpointing the trouble spot has now enabled surgeons to remove it in some patients.
Such brain surgery is usually reserved for epilepsy patients with single auras whose seizures can’t be controlled with medication. Patients with multiple auras, which are assumed to originate from multiple trouble spots, have been considered poor candidates for surgery, says study coauthor Prakash Kotagal of the Cleveland Clinic.
Using brain scans and electroencephalograms, he and his colleagues created detailed maps of the brains of 19 people who regularly experienced multiple auras. The doctors used these maps to track the misfiring pattern of each sequence of auras back to a single starting point, which became the target of surgery.
Six months later, 10 of the 19 patients remained free of seizures, the team reports in the Aug. 21 Neurology.
The technique seems to work only in the right hemisphere of the brain, which is less essential to language and consciousness than the left is, Kotagal says. Patients with multiple auras traceable to the right hemisphere can better describe them to doctors before a seizure occurs, he says.
