A Potential Alternative Treatment for Drug-Resistant Epileptic Patients

Epilepsy is a neurological disorder characterized by repeated seizures that affects approximately 50 million people worldwide. These seizures are signs of hypersynchronous neuronal activity (HNA)—excessive, unsynchronized neuronal activity in the brain—and are triggered by a variety of diseases/conditions that occur at a wide range of ages. There is currently no cure for epilepsy, but many cases can be controlled with medication. When epilepsy cannot be controlled by medication, (approximately 30% of cases) surgery may be considered. This typically involves removing, or resecting, an area of the brain where the seizure originates, using electrode arrays to guide the surgery by mapping the seizure.

In this procedure, neurosurgeons determine which areas to resect by placing the array on subdural tissue and looking for specific neural signals recorded from the array. The arrays currently used to record seizure activity in patients during surgery are quite bulky, consisting of electrodes attached to a stiff rubbery base “about the thickness of a credit card” (Stimson). They are also not flexible enough to conform to the brain’s many folds, providing only limited coverage. Additionally, since each electrode sits above tens of millions of neurons, it is quite difficult for neurosurgeons to determine exactly where the problematic neurons are located.

Recently, however, Jonathan Viventi, PhD, from the University of Pennsylvania, has developed a new generation of ultra-thin and flexible silicone active electrodes that seem to address all of the design constraints of the current array . The new array “is made of a pliable material that is only about one quarter the thickness of a human hair. It contains 360 electrodes and built-in silicon transistors, which allow for minimal wiring and dense packing of the electrodes” (Stimson). The flexibility of the array allows it to “reach into grooves that are inaccessible to conventional arrays” (Stimson). Researchers hope that they can eventually use the flexible array technology to identify specific “spiral” brainwaves known to occur in people with epilepsy, then monitor and possibly control siezures. Brian Litt, M.D. of Penn thinks they will soon be able to “model the spirals and determine what kind of waveform can stop them. Or [they] can watch the spirals terminate spontaneously and try to reproduce what [they] see by stimulating the brain electrically" he says.

This newly discovered method is much less invasive than the current surgical procedure, and is certainly a step forward in the treatment of drug-resistant epileptic patients.

http://www.nih.gov/news/health/nov2011/ninds-13.htm