DBS for OCD and Tourette syndrome
Deep brain stimulation (DBS) has been used at Mayo Clinic to successfully treat hundreds of patients with essential tremor, Parkinson's disease and dystonia. Mayo Clinic neurosurgeons are now offering DBS as a treatment option for patients with refractory obsessive-compulsive disorder (OCD) and Tourette syndrome. DBS for OCD is provided through a humanitarian device exemption granted by the Food and Drug Administration; DBS for Tourette is available in limited cases for clinical care.
Although the number of patients treated so far is fairly small, "we are seeing that DBS can be highly effective for OCD and Tourette," says Kendall H. Lee, M.D., Ph.D., a consultant in Neurosurgery at Mayo Clinic in Rochester, Minnesota.
"From a psychiatric perspective, refractory OCD is one of the most disabling diseases in psychiatry," notes Mark A. Frye, M.D., chair of Psychiatry and Psychology at Mayo Clinic's campus in Minnesota. "For the right patient, this intervention can be life-restoring and life-saving."
Refractory, severe conditions
Patients who have DBS treatment for OCD at Mayo Clinic typically haven't responded to two or three types of conventional pharmacotherapy, augmentation strategies and structured cognitive behavioral therapy (CBT). "We do a careful assessment to make sure that the evidence base for how we treat OCD has been utilized, because we don't want to use DBS if conventional treatments haven't been tried," Dr. Frye says.
The conditions of patients who haven't responded to conventional treatment can be disabling. Dr. Frye cites a young man with OCD and a history of 10 psychiatric hospitalizations, and secondary complicating features of depression. "He was plagued by recurring thoughts of sanitation and disorderliness, and compulsive behavior where he would spend hours washing his hands, engaging in ritualistic behavior, and counting," Dr. Frye says. "Activities that most people might do for several seconds a day, he would do for several hours a day." The patient was unable to finish college or to develop a social support network or a significant-other relationship.
Since treatment with DBS, the young man has returned to college and is looking for part-time work. "By all the rating scales we're using, his symptoms are 60 to 70 percent better," Dr. Frye says. "The associated functional improvement has really been dramatic."
As for Tourette, Dr. Lee cites a young man with a severe tic that caused his neck suddenly to swivel powerfully. Although the patient was on strong medication and, as a result, experienced constant sleepiness, the tic remained severe, prompting concern of possible cervical spinal injury. After DBS, the patient's tic significantly abated, and he was able to reduce his medication.
The January 2012 issue of Mayo Clinic Proceedings contained a report on that patient and two others with refractory Tourette, all of whom had excellent outcomes after treatment with DBS. Stimulation was generally well-tolerated, and some degree of efficacy against tics was noted immediately. One year after treatment, the patients had a mean reduction of 70 percent in the Yale Global Tic Severity Scale score.
DBS, then CBT
The procedure for performing DBS for OCD is similar to the DBS procedure for movement disorders. Patients are awake, with their heads in a stereotactic frame, so they can speak with the surgeon. "It is very helpful for us to know the effect of stimulation intraoperatively," Dr. Lee says. The ventral capsule/ventral striatum is targeted.
However, for Tourette, DBS is often done under general anesthesia. "A lot of these patients have such severe neck tics that it would be very dangerous to have them awake in a stereotactic frame," Dr. Lee says. The target for Tourette syndrome is the centrum-median/parafascicular nucleus of the thalamus.
After DBS, it is important for patients to resume CBT. "The neurosurgical intervention can alleviate terribly disabling symptoms and the associated complete functional disability related to those. But more work is needed beyond the neurosurgical procedure," Dr. Frye says. "In fact, we find that after surgery, patients can engage in therapy in a much more beneficial way than before surgery."
The mechanism by which DBS benefits patients isn't fully understood. "But over the past 10 years in our Neural Engineering Laboratory, we have discovered — using fMRI, electrochemistry and electrophysiology — that we are really modulating neurocircuits in the brain," Dr. Lee says. "We have some understanding of that process for patients with movement disorders, but we know much less about how it works in psychiatric circuits."
For more information
Savica R, et al. Deep brain stimulation in Tourette syndrome: A description of 3 patients with excellent outcome. Mayo Clinic Proceedings. 2012;87:59.