SAVANNAH, GA. – Deep brain stimulation shows potential for treatment of geriatric psychiatric disorders, particularly treatment-resistant depression and obsessive-compulsive disorder.
Deep brain stimulation (DBS), an effective therapy for Parkinson's disease and essential tremor, may hold promise for treatment of geriatric psychiatric disorders, Dr. Paul Holtzheimer said in a symposium on neuromodulation therapies at the meeting.
Research into DBS for treatment-resistant depression (TRD) and for obsessive-compulsive disorder (OCD), as well as for other psychiatric disorders, has been advancing, noted Dr. Holtzheimer of the department of psychiatry and behavioral sciences at Emory University, Atlanta. But more studies into efficacy, mechanisms of action, and side-effect profile – and especially long-term effects – are needed.
DBS delivers targeted electrical stimulation into the brain through a device that consists of an electrode connected to an insulated wire, inserted through a small opening in the skull. The wire is run under the skin of the head, neck, and shoulder, connecting the electrode to an implantable pulse generator (a “pacemaker”), which is implanted near the collarbone.
One advantage of a DBS device is that it can be tuned, Dr. Holtzheimer said. The electrode has four contacts, allowing the stimulation level to be adjusted and revised.
Implantation is a relatively safe procedure – “as simple as it can be,” Dr. Holtzheimer said – with a low complication rate (around 10%). The most common complication is infection; stroke is a less common but far more worrisome one, he said.
Early research in TRD suggests efficacy and safety for subcallosal cingulate, ventral capsule/ventral striatum (VC/VS), and nucleus accumbens targets. Dr. Holtzheimer called the results so far “reasonably positive.” Multicenter trials are underway for the subcallosal cingulate and VC/VS targets.
The OCD data also suggest reasonable efficacy and safety for the VC/VS, inferior thalamic peduncle, and subthalamic nucleus targets, but not the nucleus accumbens.
In 2009, the Food and Drug Administration approved a humanitarian device exemption for the use of DBS to treat OCD (VC/VS target).
The progress is encouraging, but the lack of randomized, placebo-controlled data means that long-term safety and efficacy have yet to be established, Dr. Holtzheimer cautioned. Moreover, safety and efficacy have yet to be tested in geriatric populations, and those patients are not part of the ongoing trials.
There's no reason to believe that DBS would be less safe or effective in geriatric populations, observed another member of the neuromodulation panel, Dr. William McDonald, professor of psychiatry and behavioral sciences at Emory University.
Looking ahead, questions abound, Dr. Holtzheimer acknowledged: Is late-onset depression a completely different biology from depression in younger populations? Can clinicians extrapolate efficacy to an older population?
He also pointed out that it may take months of DBS therapy before it becomes effective. It does not replace medications or psychotherapy, but it may enhance other therapeutic approaches, such as cognitive-behavioral therapy, he said.
Meanwhile, researchers are starting to look at other psychiatric indications for DBS. For example, research is underway in Toronto to explore its use in dementia, Dr. Holtzheimer said.
Dr. Holtzheimer is a consultant for St. Jude Medical: Neuromodulation, a site of one of the trials for DBS in TRD.