Deep Brain Stimulation for Obsessive-Compulsive Disorder
Deep brain stimulation (DBS), which is most often used to treat movement disorders, is approved for Obsessive-Compulsive Disorder (OCD) treatment under a Humanitarian Device Exemption. OCD must be considered chronic, severe, and treatment-resistant for a patient to be eligible for DBS therapy.
DBS may be considered for a patient who...
- Has a diagnosis of OCD with a documented duration of at least five years
- Has OCD rated as a severe or extreme illness (YBOCS ≥ 28)
- Has failed to improve following treatment with at least three selective serotonin reuptake inhibitors (SSRIs), clomipramine, and augmentation with at least 2 antipsychotics
- Has completed adequate trials of cognitive behavior therapy (exposure and response prevention)
- Is 18-years-old or older
DBS is not appropriate for a patient who...
- Has hoarding as a primary subclassification of OCD
- Has another serious psychiatric disorder (for example, personality disorder, psychotic disorder, or bipolar disorder). However, a patient with anxiety and/or depression in addition to OCD may still be considered a candidate for DBS.
- Has substance abuse issues
- Is pregnant
- Has had previous surgery to destroy the region of the brain that will be the target of stimulation (gamma knife, thermal ablation, radiofrequency ablation, cingulotomy)
- Has another neurological disorder
- Has a cognitive disorder or dementia
- Is at imminent risk of suicide
Neurosurgeon Mark Richardson, MD, PhD, works with Robert Hudak, MD, Jordan Karp, MD, and Susanne Ahmari, MD, PhD and in the Department of Psychiatry to evaluate patients with OCD who may benefit from DBS. Pre-surgical evaluation for DBS to treat OCD requires a referral from the patient’s current treating psychiatrist as the first step. The remainder of the pre-surgical evaluation process includes:
- Letter of referral from the patient’s current treating psychiatrist, and also from the treating therapist if available
- Transfer of records
- Evaluation by Dr. Hudak or Dr. Ahmari, who may recommend additional treatments before proceeding with the remainder of the DBS evaluation process
- Evaluation by a second psychiatrist that is part of our DBS team may be necessary to confirm a patient’s candidacy
- Consultation with Dr. Richardson to review the surgery
- MRI of the brain
- Neuropsychological testing
- Additional testing may be requested
Once these steps are completed, our entire DBS for OCD panel, including members from psychiatry, neurosurgery, neuropsychology, and the OCD community meet to review the case. At this meeting, an official recommendation for or against surgery is made.
What is DBS?
DBS surgery involves placing a thin metal electrode (about the diameter of a piece of spaghetti) into the desired target in the brain and attaching it to a computerized pulse generator, which is implanted under the skin in the chest below the collarbone. All parts of the stimulator system are internal; there are no wires coming out through the skin. A programming computer held next to the skin over the pulse generator is used during routine office visits to adjust the settings for optimal symptom control. Unlike older lesioning procedures or gamma knife radiosurgery, DBS does not destroy brain tissue. Instead, it reversibly alters the abnormal function of the brain tissue in the region of the stimulating electrode. It is important to note that DBS therapy may demand considerable time and patience before its effects are optimized.
How Does DBS work?
DBS is not a cure for OCD, but it can successfully treat symptoms by disrupting the abnormal patterns of brain activity that become prominent in this disease. DBS is often described as a brain “pacemaker” because constant pulses of electrical charge are delivered at settings that are thought to restore normal brain rhythms. The exact mechanisms of this neuromodulation are still unknown.
How is the surgery performed?
DBS electrode placement in the awake patient using a stereotactic frame has been the gold-standard for the past fifteen years.
The basic surgical method is called frame-based stereotaxis, which is the traditional method for approaching deep brain targets though a small skull opening. A rigid frame is attached to the patient's head just before surgery, after the skin is anesthetized with local anesthetic. A brain imaging study is obtained with the frame in place. The images of the brain and frame are used to calculate the position of the desired brain target and guide instruments to that target with minimal trauma to the brain. In the operating room, an intravenous sedative is given, a Foley catheter is placed in the bladder, the stereotactic frame is rigidly fixed to the operating table, a patch of hair on top of the head is shaved, and the scalp is washed. After making the scalp completely numb, an incision is made on top of the head behind the hairline and a small opening, less than the size of a quarter, is made in the skull. If both sides of the brain are to be implanted, the skull opening is made on both sides before sedation is stopped and the patient is fully awoken.
Brain mapping using hair-thin microelectrodes is then used to record brain cell activity in the region of the intended target to confirm that it is correct, or to make very fine adjustments of 2 millimeters in the intended brain target to try and find the optimal location. The patient must be calm, cooperative, and silent during the mapping or else the procedure must be stopped. The brain's electrical signals are played over a speaker so that the surgical team can listen for distinctive patterns of neuronal activity that indicate the location of the recording electrode. Since each person's brain is different, the time it takes for the mapping varies from about 30 minutes to up to two hours for each side of the brain. When the correct target site is confirmed with the microelectrode, the permanent DBS electrode is inserted and tested for efficacy and stimulation-induced side effects.
What happens after surgery?
Patients are typically discharged from the hospital 1-2 days after surgery. The pulse generator is placed in a second separate outpatient surgery a few days or a few weeks after the brain surgery. The patient returns to the office a few weeks after surgery to turn on the DBS and make initial programming adjustments. This first visit may take between 1-3 hours. The effects of DBS are typically not immediate. It may take several months or even a year to achieve optimal results. Optimization of DBS requires multiple office visits which may be as frequent as every 2-4 weeks initially. Patients considering DBS for treatment of their OCD must be willing to make this serious time commitment before proceeding with surgery.
Referrals for DBS evaluations should be sent from the patient's treating psychiatrist to Danielle Corson, PA-C, at (412) 864-3421 (phone) or (412) 647-4775 (fax).
Watch KDKA-TV report on DBS for OCD
Watch a KDKA-TV news report, featuring R. Mark Richardson, MD, that talks about how deep brain stimulation can help patients with severe obsessive-compulsive disorder.