Brain pacemakers can be reprogrammed to adjust to any change in the patient's condition or to progression of symptoms that may occur over time. It is a dynamic therapy.
Researchers reported last week that two studies show a “brain pacemaker” can effectively treat depression and obsessive-compulsive disorder. Devices implanted in the chest, with leads that send electrical impulses to parts of the brain, have already been approved to treat movement disorders, such as Parkinson’s disease, essential tremor and dystonia.
The remarkable new surgical procedure that has been likened to implanting a "pacemaker" in the brain is the result of a series of studies conducted by Ali Rezai, MD, head of neurosurgery at the Cleveland Clinic. Rezai, who led the studies, said the technique—known as deep brain stimulation—helped the most severely depressed patients improve significantly. Rezai is one of a new breed of neurosurgeons called a functional neurosurgeon, who treats disabling disorders with sophisticated computer equipment.
Researchers from Butler Hospital/Brown Medical School, Massachusetts General Hospital and Harvard Medical School were also involved in the depression study. Rezai says there were no serious side effects in using the Medtronic device.
They call the procedure deep brain stimulation (DBS). It's working wonders for patients with Parkinson's and other movement disorders such as essential tremor and dystonia. But doctors at The Cleveland Clinic have even higher hopes for DBS. They believe that in coming years, it may prove to be an effective treatment for a wide range of conditions.
The trial treating obsessive-compulsive disorder (OCD) included 26 patients who were followed for three years and also showed marked improvement. Butler Hospital/Brown University, University of Florida and University of Leuven also contributed to the OCD study. Medtronic has an application before the US Food and Drug Administration for approval to use deep brain stimulation to treat OCD.
Similar means of treating mental disease were initiated in 2005, when the FDA approved the Cyberonics Inc. implantable device for treatment-resistant depression; it sends signals to the brain via the vagus nerve in the neck.
"The brain pacemaker is the state-of-the-art in medical engineering," says Rezai. "Once it is implanted, it emits finely tuned pulses of energy that relieve symptoms without the cell damage and destruction associated with traditional brain surgery. The pacemakers can be reprogrammed to adjust to any change in the patient's condition or to progression of symptoms that may occur over time. It is a dynamic therapy. Stimulation settings can be modified to maximize symptom reduction while minimizing both complications and side-effects. The procedure is also completely reversible."
Brain stimulation as a concept has been around since the 1940s. Only recently, however, have neuroscientists had the knowledge necessary to put it to use.
Rezai says that surgeons can target any structure of the brain with one-millimeter accuracy to identify where confused or abnormal nerve signals are generated. Such accuracy allows the surgeons to implant the brain pacemaker's tiny electrode precisely where it is needed to sooth these minute, chaotic abnormalities.
While it is not a cure, DBS can improve the quality of life for patients for whom other therapies have failed. In addition, a number of studies are underway to investigate the possibility that DBS may slow the progression of Parkinson’s disease.