Cortical Brain Stimulation Offers Hope To People With Treatment-Resistant Major Depression

The World Health Organization rates major depression as the top cause of disability worldwide, with an estimated 340 million people suffering from an episode of major depression every year. While most patients with major depression find relief through a combination of psychotherapy and medication, about 20 percent of patients fail to respond. Patients who are most resistant to medications, psychotherapies, and electroconvulsive therapy (ECT) have little hope of recovery, and suffer a heightened risk of suicide and mortality. Sadly, statistics show that the suicide rate in people with major depression is as high as 15 percent.


Electroconvulsive therapy (ECT) is effective in approximately 70 percent of cases in which antidepressant medications do not provide adequate relief of symptoms. However, as many as 20 to 50 percent of patients who initially respond well to ECT treatment, suffer a relapse within six months, therefore, periodic maintenance therapy is often required. For those patients who are resistant to these therapies, more invasive approaches have been used, including vagus nerve stimulation and more recently, deep brain stimulation.


Researchers at three U.S. institutions investigated the use of a new form of stimulation in patients with medically refractive major depression. The results of this study, Long Term Follow-up of Cortical Stimulation to Treat Major Depressive Disorder, will be presented by Emad N. Eskandar, MD, Masachusetts General Hospital/Harvard Medical School, 10:30 to 10:44 am, Tuesday, May 5, 2009, during the 77th Annual Meeting of the American Association of Neurological Surgeons in San Diego. Co-authors are Douglas Kondziolka, MD (University of Pittsburgh Medical Center), and Brian Kopell, MD (Medical College of Wisconsin).


"Imaging and transcranial magnetic stimulation studies have demonstrated that the left dorsolateral prefrontal cortex (DLPFC) area of the brain plays a critical role in patients with major depressive disorder (MDD). These findings prompted research in which we used an investigational epidural cortical stimulation system to deliver targeted stimulation to the left DLPFC in 12 patients with MDD," stated Dr. Eskandar.


The 12 patients were randomized to single blind active or sham stimulation for 8 weeks, and then all subjects received active stimulation. One patient was excluded from analysis due to a protocol deviation. During the procedure, the electrodes were placed epidurally, outside the dura, through a small craniotomy. Outcome assessments included the Montgomery-Asberg Depression Rating Scale (MADRS), the Hamilton Depression Rating Scale (HDRS), and the Global Assessment of Functioning (GAF). The following results were noted:


-- At 8 weeks, HDRS decreased by 22 percent (active: n=6) versus 3 percent (sham: n=5).


-- MADRS decreased 22 percent (active) versus 8 percent (sham).















-- GAF increased 23 percent (active) versus 12 percent (sham).


-- In all patients, continued improvement was seen at 6 months (average HDRS: 20 percent) and 12 months (average HDRS: 33 percent).


-- At 12 months, patients whose electrodes were implanted >20 mm from the precentral sulcus averaged a 59 percent improvement in HDRS compared to a 12 percent improvement in patients (n=6) with electrodes