When a patient has drug-resistant epilepsy, sometimes called refractory epilepsy, and other conservative treatments fail to control one's seizures, surgery or the implantation of stimulation device are the next best options.
There are three types of stimulation devices for epilepsy. In all types, the devices send electrical signals to the brain to prevent the electrical bursts that cause seizures.
Devices
VNS
The vagus nerve stimulator (VNS) is implanted under the skin, near your collarbone. A wire (lead) under the skin connects the device to electrodes attached to the vagal nerve that goes to your brain. The doctor programs the device to produce weak electrical signals that travel to your brain at regular intervals to prevent seizures.
RNS
The responsive neurostimulator (RNS) is implanted in the skull, and lead wires connect the device to the area of the brain that is causing the seizures. The doctor programs the device to notice abnormal electrical activity in the brain and send electrical signals to that area of the brain. Unlike a VNS, a RNS must be implanted at a Comprehensive Epilepsy Center by neurosurgeons with adequate experience. Baylor Medicine is a Comprehensive Epilepsy Center.
DBS
A deep brain stimulation (DBS) system delivers chronic stimulation to the anterior nucleus of the thalamus (ANT), a small brain structure involved in the spread of an initially localized seizure. The doctor implants the device and then it is programmed in the outpatient clinic by an epilepsy specialist.
What's the difference?
The DBS system for epilepsy delivers ongoing, or open loop, stimulation intended to alter brain activity just enough to prevent or limit the initiation or spread of a seizure. In contrast, closed loop or responsive stimulation, delivers stimulation only when brain activity patterns suggest a seizure is beginning or very likely to occur.
Patient Story
A combination of seizures and serious medication side effects forced Michael to leave his career in law enforcement back in 2001. He wasn’t a candidate for epilepsy surgery but was still searching for a better option than trying more medications, none of which controlled his seizures for more than a few months.
Brain stimulation therapies for epilepsy
https://www.ninds.nih.gov/About-NINDS/Impact/NINDS-Contributions-Approved-Therapies/Brain-stimulation-therapies-epilepsy