Bilateral deep brain stimulation of the anterior limb of the internal capsule shows promise as treatment for patients with intractable major depression, according to a presentation at the annual meeting of the American Association of Neurological Surgeons.

“Since 2001, this team of investigators has been using deep brain stimulation (DBS) for treatment of obsessive compulsive disorder (OCD). Because DBS for OCD showed significant benefits in improving patient’s anxiety and obsessions, as well as improvements in co-morbid depression, the research team initiated a new study analyzing the effects of DBS on patients with major depression,” Rezai explained.

The technique has been used to treat intractable pain for several decades, and has seen usage expanded recently to Parkinson’s disease and other movement disorders. Research is studying its potential in patients with intractable epilepsy.

The surgery involves implantation of tiny electrodes into specific parts of the brain. The electrodes emit tiny pulses of electrical stimulation to block abnormal neuronal activity. Success is dependent on the surgical team’s ability to precisely pinpoint the specific brain area for stimulation. An advantage of the technique is that it is reversible, nondestructive, and can be modified by adjustment of the stimulator settings after implantation.

In the current study, 6 patients, 4 women and 2 men (average age, 48) with a history of depression resistant to other treatments including medication, psychotherapy, and electroconvulsive therapy (ECT) were enrolled.

Bilateral leads were implanted stereotactically in the ventral anterior internal capsule. Participants underwent standardized and detailed psychiatric, quality-of-life, and neuropsychological assessments on a regularly scheduled basis, both before and after their procedures.

At a minimum of 6 postoperative months, 4 of the 6 patients showed a clinically significant reduction in depression severity of 50 percent or greater on the Montgomery-Asberg Depression Rating Scale. Quality-of-life measures improved as well, and patients showed progressive improvements in mood and functioning over time. One patient experienced persistent occipital pain that was alleviated with repositioning of a subcutaneous connector wire.

Rezai also commented on patients with obsessive compulsive disorder (OCD) who had been previously treated by the same team: “In following 9 patients for a minimum of 2 years, we concluded that bilateral deep brain stimulation of the anterior limb of the internal capsule is a safe and effective therapy for patients with intractable OCD that were previously unresponsive to all other available therapeutic alternatives.”