12/02/2010 - After more than 15 years of treating movement disorders with deep brain stimulation, Vanderbilt University Medical Center is now 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 there is a similar imbalance in the cognitive system with OCD,” said Joseph Neimat, M.D., 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 a very extended period of time. Most of these patients have had it for over a decade and every medication available has failed,” Neimat said.
Ron Salomon, M.D., associate professor of Psychiatry, has studied experimental DBS for depressed patients and said 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 said.
Salomon expects similar results when Vanderbilt activates its first stimulator in an OCD patient, but 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,” Salomon said.
A candidate is first referred by his or her psychiatrist and a conference is held with VUMC's neurologists, neurosurgeons, psychiatrists and ethicists to review the case.
The candidate goes through informational and diagnostic interview, psychological testing and an MRI to rule out abnormal brain lesions. Once these criteria are met, the patient will undergo surgery to place the implant.
“We are not taking this lightly,” Neimat said. “We're very serious about which patients we pick, and we want to be sure we're picking patients who don't have other options. And also that we can do it safely and expect the best outcomes.”
VUMC currently has two patients who have completed these steps and are awaiting insurance approval before surgery is performed.
Neimat expects that DBS will eventually be applied in other brain diseases, such as depression and Tourette syndrome.
“This is probably the first wave of quite a few therapies,” he said.
“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.”