By Kristen Hallam
LONDON — Deep-brain stimulation, a technique that has shown promise in treating mental disorders and Parkinson's disease, may also help severe and enduring anorexia, a small, early-stage study suggests.
The main goal of the six-patient study was to see whether the pacemaker-like device, made by Medtronic, could be implanted safely. While one patient suffered a seizure two weeks after the procedure, at least half of those who received the implant showed improvements in mood and body mass, according to the findings published today in The Lancet medical journal.
The findings add to potential uses of deep-brain stimulation, which has been shown to be effective in epilepsy, chronic pain and obsessive-compulsive disorder. Medtronic's Activa device is approved in the U.S. and Europe to treat Parkinson's and tremors. As many as 20 percent of anorexia patients don't respond to therapy and as many as 11 percent of anorexics die of the condition, the researchers said.
"New effective treatments for these patients are sorely needed," Janet Treasure and Ulrike Schmidt, professors at King's College London's Institute of Psychiatry, wrote in a comment accompanying the study. "The findings of this proof-of- concept study are promising and will give hope to patients with especially pernicious forms of the disorder and their families."
In deep-brain stimulation, a battery-operated device shoots electrical currents into a targeted area of the brain, similar to pacemakers used to manage heart rhythms. The approach, which is minimally invasive and completely reversible, has been used for more than 25 years to regulate dysfunctional brain circuits, according to the study.
Scientists at the Krembil Neuroscience Centre and University Health Network in Canada used magnetic resonance imaging to identify an area of the brain that has been used for deep-brain stimulation in patients with depression. Electrodes were then implanted into that area in each patient and connected to a pulse generator, which was inserted under the skin.
The researchers activated the device 10 days after the surgery and measured changes in patients' mood and anxiety levels to identify the correct level of stimulation, according to the study. Changes in mood and body mass index were measured with standardized tests.
"The finding of improvements in mood and anxiety in patients who were still underweight is especially striking, in view of the well-known poor response of underweight patients to conventional pharmacotherapies or psychotherapies," Andres Lozano, one of the researchers, said in a statement.
The six female patients were between 24 and 57 and had been suffering from anorexia for between four and 37 years. The patient who had a seizure two weeks after the procedure had her device shut off and reactivated a week later, with no recurrence. The seizure was probably linked to a metabolic disorder she had as a result of her anorexia, the researchers said. Other adverse events included a panic attack during surgery, nausea and pain, they said.
Minneapolis-based Medtronic and St. Jude Medical Inc. of Saint Paul, Minnesota, are among companies that market implantable devices for deep-brain stimulation treatment of neurological illnesses.
The study was funded by the Klarman Family Foundation in Boston and the Canadian Institutes of Health Research.