Development of high resolution, multiplexed electrode arrays: Opportunities and challenges

More than one third of the world's 60 million people with epilepsy have seizures that cannot be controlled by medication. Some of these individuals may be candidates for surgical removal of brain regions that generate seizures, but the chance of being seizure free after epilepsy surgery is as low as 35% in many patients. Even when surgery is successful, patients risk neurological deficits like memory loss and speech difficulties. The need for new treatments is clear. A central barrier to better treatments for epilepsy is technological: we do not have devices capable of interfacing with the brain with small enough electrodes over large enough regions to map epileptic networks in sufficient detail to enable treatment. Our collaborative group has developed new implantable brain devices to address this challenge. Our devices, made from flexible silicon nanoribbons, can record from these very small brain regions, with electrodes ½ millimeter apart or less, and can be scaled up to clinically useful sizes, on the order of 64 cm(2). They consist of thousands of individually controllable microelectrodes.