Charleston, SC — Bilateral epidural prefrontal cortical stimulation (EpCS), a new neurosurgical procedure, may prove helpful for patients with treatment-resistant depression. EpCS was found to be generally safe and provided significant improvement of depressive symptoms in a small group of patients, according to lead researcher Ziad Nahas, M.D., at the Medical University of South Carolina.
Treatment-resistant depression is a recurrent psychiatric illness and a leading cause of premature mortality due to suicide and associated medical conditions. In the U.S., more than 3.2 million patients are diagnosed with treatment-resistant depression. Typically, patients have tried several medications and treatments without success or improvement.
EpCS targets electrical stimulation to the anterior frontal poles and the lateral prefrontal cortex. "We focused on these two regions because they are part of a larger brain network critical in regulating mood. Both play complementary roles integrating emotional and cognitive experiences and offer a distinct opportunity for targeted antidepressant treatments," said Dr. Nahas, an associate professor of Psychiatry, Physiology, and Neuroscience and Director of the Mood Disorders Program at MUSC.
"Cortical stimulation has several advantages, provided that it shows efficacy in treating depression," Dr. Nahas said. "It is reversible, non-destructive, and potentially safer than other forms of invasive brain stimulation since the stimulating paddles don't come in direct contact with the brain." His team included MUSC neurosurgeon Istvan Takacs, M.D., and MUSC anesthesiologist Scott Reeves, M.D.
Five patients participated in Dr. Nahas’ EpCS research study and were implanted with EpCS over the anterior frontal poles and the lateral prefrontal cortex bilaterally. Only patients who failed to respond to several antidepressant treatments—including medications, psychotherapy, transcranial magnetic stimulation, vagus nerve stimulation, or electroconvulsive therapy—were included in the study.
Patients were closely followed and regularly evaluated using standard clinical ratings. After seven months, the average improvement was 54.9 percent based on the Hamilton Rating Scale for Depression and 60.1 percent on the Inventory of Depressive Symptoms Self Report. Three of the patients reached remission. One patient experienced a scalp infection that required removing the implants over the left hemisphere.
"These preliminary results are encouraging but not definitive," said Dr. Nahas. "Now that we have a proof of concept, we should aim at studying bilateral EpCS in larger placebo-controlled studies."
The study was funded by the National Alliance of Research in Schizophrenia and Affective Disorders (NARSAD), a charity dedicated to mental health research.