The new study marks the first time that deep brain stimulation has been tried in that brain region. And it's an important first step to show that not only could these three severely obese people get through the surgery, but they also seemed to have no serious effects from the brain stimulation, said Dr. Casey Halpern, a neurosurgeon at the University of Pennsylvania who was not involved in the research.
"That shows us this is a therapy that should be studied further in a larger trial," said Halpern, who has done animal research exploring the idea of using deep brain stimulation for obesity.
"Obesity is a major problem," Halpern said, "and current therapies, even gastric bypass surgery, don't always work. There is a medical need for new therapies."
The three patients in Whiting's study were examples of that medical need. All were severely obese and had failed to shed weight after gastric bypass surgery -- the current last-ditch treatment option.
During the study period, the patients did have some side effects from deep brain stimulation -- nausea, anxiety and feeling "too hot or flushed" -- but they were short-lived, the researchers said. And there was some evidence that the brain stimulation was having effects. In lab tests, Whiting's team found that the deep brain stimulation seemed to spur short-lived spikes in resting metabolism.
Then, after the deep brain stimulation was programmed to the settings that seemed to boost metabolism, two patients shed some pounds -- 12 percent to 16 percent of what they weighed before the DBS settings were "optimized."
"There was some weight loss, but it was transient," Whiting said. Now a key question is, what is the right setting for the deep brain stimulation to encourage lasting weight loss? Whiting said his team is continuing to follow these three patients to try to figure that out -- and to keep monitoring safety.
Although deep brain stimulation is considered a generally safe therapy for the right patients, it is a major undertaking that requires two surgeries -- one to implant electrodes in the brain and another to place the neurostimulator. The potential risks include infection, a blood clot or bleeding in the brain, or an allergic reaction to the DBS parts.