In the first U.S. clinical trial of its kind, deep-brain stimulation (DBS) therapy -- a treatment that has proven effective for other neurological conditions such as Parkinson's disease -- is being tested on patients with epilepsy to determine if it can help reduce the frequency of seizures. Emory University and 11 other sites are taking part in this research study, which is being funded by Medtronic, Inc., the maker of implantable devices that provide controlled pulses of electrical stimulation to a specific area in the brain.
"About 20 percent of patients with epilepsy do not have good control of their disorder because anti-epileptic medications aren't effective and they don't qualify for standard epilepsy surgery," says Thomas R. Henry, MD, associate professor of neurology, Emory University School of Medicine, and principal investigator (PI) of the clinical trial at Emory. "DBS opens up another avenue for some of the harder-to-treat seizures."
Epilepsy is a neurological condition that produces brief disturbances in the normal electrical functions of the brain, often causing seizures. It affects about one percent of the population, approximately 2 million Americans.
The study is called the Stimulation of the Anterior Nucleus of the Thalamus for Epilepsy (SANTE) trial. The thalamus is one of the areas of the brain that is most involved in seizure circuitry and development, according to researchers. The DBS therapy is thought to work by disrupting the circuits that generate epileptic seizures.
"Animal studies involving stimulating the anterior nucleus of the thalamus in rats showed termination of seizures," says Robert Gross, MD, PhD, assistant professor of neurosurgery and co-PI of the study at Emory.
Under general anesthesia, participants in the study will have a lead (a thin wire electrode) implanted in the anterior nucleus of the thalamus on both sides of the brain, which will be connected to a single pacemaker-like device (operated by battery) implanted under the skin, near the collarbone. The leads and pacemaker-like device are then connected by extension wires, which are threaded under the skin of the neck. The stimulation from the device will deliver electrical pulses directly to the targeted areas in the brain through the extension wires and leads. All of the stimulator components can be implanted during one surgical procedure.
All study participants will be implanted with the devices, however not all participants will receive stimulation right away. One month following implantation, participants will be randomly selected to either receive stimulation or to receive no stimulation (the control group). During this time, participants will be asked to count any seizures that occur. Neither participants nor researchers will know who is receiving what treatment during this double-blind phase of the study.
After the double-blind period, everyone will then receive stimulation. Participants will remain in the study for a total of 13 months, with long-term follow-up.
"The SANTE study is significant because it will enroll a larger number of participants than past pilot studies looking at DBS and epilepsy," says Dr. Henry. "It will also include a longer period of time comparing patients who have stimulation versus no stimulation in the anterior nucleus of the thalamus to determine if seizure response is better with thalamic stimulation."
Deep-brain stimulation can only be used in an investigational trial setting for epilepsy until and unless it is FDA approved. However, the FDA has approved DBS to treat Parkinson's disease and essential tremor. Under a special exemption by the FDA, it can also be used to treat dystonia.
To find out more about this study, please call Emory Health Connection at (404) 778-7777.