October 21, 2008
Depression Treated With Magnetic Device
The first noninvasive brain stimulator to treat depression has been approved by the Food and Drug Administration. The device sends short bursts of magnetic energy through the skull. These small electric charges makes brain cells fire and eliminates the use of either surgically implanted electrodes or electroshock therapy.
The FDA approved the treatment that is available only by prescription based on a study that showed modest improvement (24%) in patients treated by this approach compared to a placebo (12%) consisting of a fake treatment that imitated the magnetic device. The comparison were based on standard depression measures after six weeks. The National Institute of Health is conducting a study that involves 260 patients. Initial results may be ready by next year.
The FDA approval was based on the results from 164 patients who had failed to improve after one treatment with an antidepressant.
This new approach is called Tran cranial magnetic stimulation (TMS). NeuroStar therapy by Neuronetics Incorporated cannot be used by all depression patients. It is reserved for those who received no relief from their first antidepressant and do not want to try a succession of different medications.
According to Dr. Mark George of the Medical University of South Carolina, a pioneer in the use of TMS, this will open up a whole new area of medicine. This new field is moving ahead of noninvasive electrical stimulation of the brain.
TMS can cost $6,000 to $10,000 depending on the number of treatments a patient needs said Dr. Philip Janicak of the Rush University Medical Center in Chicago. Janicak helped lead the NeuroStar study. It is more expensive that medication but much cheaper than depression devices that require surgery.
TMS has been used for years as a tool in brain research studies. Placing a powerful magnet over a specific spot in the brain where motion is controlled can produce involuntary motion like the movement of an arm. Researchers noticed that these magnetized pulses were also producing brain activity. Scientists became interested in using that activity in a way to treat disease, stroke rehabilitation and other brain disorders.
To treat depression, physicians aim the magnet at prefrontal cortex. In order to find the patient's motor-control region, the first pulse is directed from the top of the head. Once the region is located, the magnetic device is moved 5 centimeters forward and the patient receives about 3,000 pulses over 40 minutes. The treatment is repeated five times a week for about six weeks. In theory, the stimulated brain cells will produce a reaction that penetrates into regions deeper in the brain. These regions are involved with mood.
TMS seems to be safe. Patients in the NeuroStar study were seizure free and experienced no memory problems like those produced by shock therapy. No other reactions were observed throughout the body, and the most common complaint was headaches.
At least one patient, 60 year old Steve Newman of Washington, D. C., reported significant improvement. Newman, suffering form depression since he as a teenager, experience a major improvement in his depression measurements. He receives a maintenance treatment about once a month.
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