A pilot study reveals that an implanted brain stimulator significantly decreased bingeing episodes and assisted patients in losing weight.
According to researchers at the Perelman School of Medicine at the University of Pennsylvania, a small device that detects food craving-related brain activity in an important brain region and reacts by electrically stimulating that region has shown promise in a pilot clinical trial in two patients with loss-of-control binge eating disorder (BED).
The trial, which was described in a paper published in the journal Nature Medicine, tracked the two patients for six months as the implanted device—of a kind often used to treat drug-resistant epilepsy—monitored activity in a part of the brain known as the nucleus accumbens.
The nucleus accumbens is involved in pleasure and reward processing and has been linked to addiction. When the device detected nucleus accumbens signals that had previously been shown to predict food cravings, it automatically stimulated that brain region, interrupting the craving-related signals. Over the course of six months, the patients reported far fewer binge episodes and lost weight.
“This was an early feasibility study in which we were primarily assessing safety, but certainly the robust clinical benefits these patients reported to us are really impressive and exciting,” said study senior author Casey Halpern, MD, an associate professor of Neurosurgery and chief of Stereotactic and Functional Neurosurgery at Penn Medicine and the Corporal Michael J. Crescenz Veterans Affairs Medical Center.
BED is thought to be the most common eating disorder in the US, affecting at least a few million individuals. It often involves binge-eating episodes without the purging of bulimia, and is typically linked to obesity. The bingeing person has a sensation of losing control over eating, therefore he or she continues to eat beyond the usual point of feeling satiated.
Cravings for particular meals precede BED episodes. In a 2018 study using mouse and human experiments, Halpern and colleagues discovered evidence that specific low-frequency electrical activity in the nucleus accumbens emerges shortly before these cravings—but not before normal, non-binge eating. The researchers stimulated the nucleus accumbens in mice to disrupt craving-related activity whenever it happened, and they discovered that the mice ate considerably less of a tasty, high-calorie meal that they would have otherwise gorged themselves on.
The device used by the researchers to capture signals from and stimulate the mice’s brains is commercially accessible and authorized for the treatment of drug-resistant epilepsy. It is surgically implanted under the scalp, with wires extending through the skull to each brain hemisphere’s nucleus accumbens.
The new study was a preliminary test of the same device and strategy in human subjects. Halpern’s team fitted each of two severely obese BED patients with the brain-stimulation devices, and, for six months, recorded signals from the devices. At times, the patients were in the laboratory, presented with buffets of their favorite foods—fast-food and candy were common items—but mostly they were at home going about their daily routines. The researchers could film the patients’ binge-eating episodes in the lab, and when the patients were at home, they self-reported the times of their episodes. The scientists observed that, as in their prior study, a distinctive low-frequency signal in the nucleus accumbens appeared in the seconds before the patients’ first bites of their binge meals.
In the next phase of the study, the brain-stimulation devices automatically delivered high-frequency electrical stimulation to the nucleus accumbens whenever the low-frequency craving-associated signals occurred. During this six-month interval, the patients reported sharp reductions in their feelings of loss-of-control, and in the frequencies of their bingeing episodes—each also lost more than 11 pounds. One of the subjects improved so much that she no longer met criteria for binge-eating disorder. There appeared to be no significant adverse side-effects.
“This was a beautiful demonstration of how translational science can work in the best of cases,” said study co-lead author Camarin Rolle, PhD, a postdoctoral researcher with Halpern’s group.
The scientists have continued to follow the subjects for another six months, and have begun enrolling new patients for a larger study. They note that, in principle, the same treatment approach could be applied to other loss-of-control-related disorders including bulimia.
Reference: “Pilot study of responsive nucleus accumbens deep brain stimulation for loss-of-control eating” by Rajat S. Shivacharan, Camarin E. Rolle, Daniel A. N. Barbosa, Tricia N. Cunningham, Austin Feng, Noriah D. Johnson, Debra L. Safer, Cara Bohon, Corey Keller, Vivek P. Buch, Jonathon J. Parker, Dan E. Azagury, Peter A. Tass, Mahendra T. Bhati, Robert C. Malenka, James D. Lock and Casey H. Halpern, 29 August 2022, Nature Medicine.
DOI: 10.1038/s41591-022-01941-w
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