After more than 15 years of treating movement disorders with deep brain stimulation, Vanderbilt is offering the procedure to patients with obsessive-compulsive disorder (OCD).
“In movement disorders like Parkinson’s disease, there is an imbalance in the brain’s motor system. The cognitive circuit is a mirror of the motor circuit, and we think a similar imbalance exists in the cognitive system with OCD,” says Dr. Joseph Neimat, assistant professor of neurological surgery. “We think DBS can be applied with similar success to what we have seen in Parkinson’s.”
Deep brain stimulation (DBS) involves a thin wire implanted into an area deep in the brain. The wire connects to a small pulse generator placed in the chest, similar to a heart pacemaker, which emits an electrical current.
Although the mechanisms of DBS are still largely unknown, it is believed that the electrical current jams the brain circuit that is firing inappropriately and puts it back in balance.
OCD, an anxiety disorder characterized by recurrent thoughts and repetitive behaviors, affects about 2 percent to 3 percent of the population.
Approximately 75 OCD patients worldwide have been treated with DBS, typically showing about two-thirds improvement in their OCD symptoms. Because it is still an emerging treatment, DBS is only used in patients who have exhausted all other options.
“Candidates for DBS have to be at the top of the standard rating scales. They have to have had the disease for an extended period of time,” says Neimat. “Most of these patients have had it more than a decade, and every medication available has failed.”
Dr. Ron Salomon, associate professor of psychiatry, has studied experimental DBS for depressed patients and says the effects of activating the stimulator are dramatic.
“When the stimulator is turned on following surgery, they will say that the sadness is gone and they feel good. Then the stimulator is turned off, and they ask what happened. It’s like this curtain has come back over them. It’s completely blind; the patient has no idea when the stimulator is being activated,” Salomon says.
Salomon expects similar results when Vanderbilt activates its first stimulator in a patient with OCD, though world literature has shown that DBS benefits most but not all recipients. “This procedure can really rescue a life. Before DBS, the patients are completely housebound. After DBS, many may get to a level where they can get out and have a life.”
A candidate is first referred by his or her psychiatrist, and a conference is held with Vanderbilt University Medical Center neurologists, neurosurgeons, psychiatrists and ethicists to review the case. The candidate goes through informational and diagnostic interviews, psychological testing, and an MRI to rule out abnormal brain lesions.
Neimat expects that DBS eventually will be applied for other brain diseases, such as depression and Tourette’s syndrome. “This is probably the first wave of quite a few therapies,” he says. “We’re enthusiastic and very hopeful that this will be a viable option for patients who really had no options before to improve their disease and improve their life.”