Deep brain stimulation is a neurological procedure that surgically implants electrodes in the brain. When placed in areas of the brain that control movement, it can treat movement disorders like tremors and placement in other areas can treat dystonia or epilepsy. The most recent Food and Drug Administration approval for this technique is for epilepsy. In each application, electrical stimulation is controlled by a neurostimulator (a pacemaker-like device). This stimulation treats the symptoms of movement disorders and other neurological conditions when medications have become less effective.
How deep brain stimulation works
Deep brain stimulation interrupts irregular signals that cause tremors and other movement symptoms. Or, it stimulates a region that acts as a “brake” to reduce seizures. Your neurologist and care team will perform a series of tests that help them determine optimal placement of the leads inside the brain and the appropriate amount of simulation. Your neurologist and surgeon will monitor you carefully for the most precise lead placement. In some cases, the procedure is done while under general anesthesia.
After the neurostimulator has been in place for a few weeks, your neurologist will program it to deliver an electrical signal that provides the most effective results while limiting side effects. This happens in-office during a series of visits over the course of weeks or months..
Leading the way in research
In 2018, the FDA approved deep brain stimulation to reduce seizures in difficult-to-treat epilepsy. Marshfield Clinic Research Institute was one of the organizations in the early research with clinical trials 13 years before FDA approval.
Dr. Evan Sandok, Marshfield Clinic Health System neurologist, participated in the research on deep brain stimulation therapy for epilepsy. “The patients would tell you that it really changed their life.”
Dr. Sandok and his research team found seven participants for the study. The trial was performed only on participants with at least six seizures a month despite trying at least three medications. Many also had tried other treatment options because stopping seizures is a top priority for someone with epilepsy.
“The big concern for us is epilepsy is potentially dangerous,” Dr. Sandok said. “People who have uncontrolled seizures not only can get injured, but they can die. It is a very rare thing, but our goal is to try and cut down on those bad seizures and reduce that risk.”
Each participant had deep brain stimulation electrodes put on the anterior thalamus in their brain by Dr. John Neal, a Marshfield Clinic Health System neurological surgeon.
“The clinic has been involved with deep brain stimulation for movement disorders for more than 20 years. It is the same technique as it is when applied to epilepsy. However, a different location and stimulation parameters than what is used for Parkinson’s and tremor patients,” Dr. Sandok said.
How it compares
Epilepsy affects about one percent of the population. About 70%of those affected with epilepsy find a medication effective at controlling their seizures.
“The typical story has been if the first medication doesn’t work, you try another and you try another, but it is sort of a plan of diminishing returns,” Dr. Sandok said.
After patients have tried three medications and continue to have seizures, each additional medication has less than a 9% chance of working. For the 30% of patients that medications doesn’t work for, the options are much more complicated.
Three pacemaker devices and brain surgery have FDA-approval. Deep brain stimulation has most recent approval. Other procedures include the vagus nerve stimulator, responsive neurostimulation and deep brain stimulation therapy. Each one has its advantages and disadvantages. You should have a conversation with your epilepsy specialist to help decide if these choices are right in your circumstance:
- Vagus nerve stimulator – This option stimulates a nerve in the neck that connects to the brain. About 30% of patients seeing at least a 50% reduction in seizures.
- Responsive neurostimulation – This option requires finding the location in the brain that is causing seizures. A wire or grid connected to the neurostimulator is placed in that part of the brain. About 40% of patients see at least a 50% reduction in seizures. Later studies have suggested that up to 70% may see at least a 50% reduction in seizures over time.
- Deep brain stimulation device – This option requires brain surgery to place the deep brain stimulator in the anterior thalamus. About 40% of patients seeing at least a 50% reduction in seizures. Later studies also have suggested that up to 70% may see at least a 50% reduction in seizures over time.