Patients with focal epilepsy that does not respond to medications badly need alternative treatments.
In a first-in-humans pilot study, researchers at the University of Alabama at Birmingham have identified a sentinel area of the brain that may give an early warning before clinical seizure manifestations appear. They have also validated an algorithm that can automatically detect that early warning.
These two findings offer the possibility of squelching a focal epilepsy seizure — before the patient feels any symptoms — through neurostimulation of the sentinel area of the brain. This is somewhat akin to the way an implantable defibrillator in the heart can staunch heart arrhythmias before they injure the heart.
In the pilot study, three epilepsy patients undergoing brain surgery to map the source of their focal epilepsy seizures also gave consent to add an investigational aspect to their planned surgeries.
As neurosurgeons inserted long, thin, needle-like electrodes into the brain to map the location of the electrical storm that initiates an epileptic seizure, they also carefully positioned the electrodes to add one more task — simultaneously record the electrical activity at the anterior nucleus of the thalamus.
The UAB team led by Sandipan Pati, M.D., assistant professor of neurology, found that nearly all of the epileptic seizures detected in the three patients — which began in focal areas of the cortex outside of the thalamus — also recruited seizure-like electrical activity in the anterior thalamic nucleus after a very short time lag. Importantly, both of these initial electrical activities appeared before any clinical manifestations of the seizures.
The UAB researchers also used electroencelphalography, or EEG, brain recordings from the patients to develop and validate an algorithm that was able to automatically detect initiation of that seizure-like electrical activity in the anterior thalamic nucleus.
“This exciting finding opens up an avenue to develop brain stimulation therapy that can alter activities in the cortex by stimulating the thalamus in response to a seizure,” Pati said. “Neurostimulation of the thalamus, instead of the cortex, would avoid interference with cognition, in particular, memory.”