Seizures seem to hit an epileptic at random moments. But scientists have discovered that bursts of electricity in the brain can precede an attack as early as 7 hours. The study may help researchers predict seizures--and possibly prevent them.
Many clinicians have long suspected that an epileptic seizure originates long before its symptoms appear; for one thing, patients sometimes perceive intuitively that a seizure is on its way. So far, though, most of the measurements of electrical activity in the brain have focused on the first few minutes before a seizure, when neurologists can pick up strong abnormal bursts of activity on an electroencephalogram.
In an attempt to look much earlier, a group led by Brian Litt, an epileptologist at the University of Pennsylvania, examined the brains of five epileptics with focal epilepsy, which begins within specific regions of the brain. The neurologists bored holes in the skull of the patients, who were undergoing evaluation for surgery, and inserted electrodes that contacted the troublesome regions. Then they measured electrical activity while waiting for a seizure to happen. The team found increasing frequency of electrical outbursts in the hours before a seizure--as if each burst sparked a new one, in a pattern unique for every patient.
The work could lead to what epileptologist Jerome Engel of the University of California, Los Angeles, calls "the holy grail": a means to predict seizures and stop them before they detonate. Litt's group outlined its vision for a device to do just that in a study, published in the journal Neuron on 26 April. The instrument would be implanted in the brain of an epileptic and detect patterns of electrical discharge. It could warn of impending seizures or even short-circuit them by delivering electrical shocks or drugs.
Although that's still a scientific dream, Harvard neurologist Daniel Lowenstein is impressed with the study. "I think it represents one of the most exciting findings in epilepsy research in the past year, with substantial therapeutic implications," he says.