Noninvasive brain stimulation — specifically transcranial direct current stimulation — may offer a novel approach to treating obesity, researchers reported at ObesityWeek 2015.
The technique can be a useful tool for modifying activity of the prefrontal cortex that may help decrease caloric intake and promote weight loss. Additionally, transcranial direct current stimulation is attractive because it has few side effects, noted study investigator Marci E. Gluck, PhD.
“Just as the light box became a home intervention for treating seasonal affective disorder, [transcranial direct current stimulation] potentially could be used at home to treat weight-related disorders,” said Dr Gluck, who is the director of behavioral sciences at the Phoenix Epidemiology and Clinical Research Branch of the National Institutes of Health’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) in Phoenix.
Dr Gluck, who presented the findings at the meeting, and colleagues studied 9 men and women with obesity who resided in the Phoenix Epidemiology and Clinical Research Branch’s metabolic ward on 2 separate 9-day visits.
On each visit, the participants ate a weight-maintaining diet for 5 days. Then for 3 days, they unknowingly received either active or sham transcranial direct current stimulation.
Participants ate and drank as much as they wanted from computerized vending machines.
Applied to the scalp, the active transcranial direct current stimulation targeted the brain region controlling behavior and reward.
The 4 individuals who underwent the sham stimulation during both visits consumed the same number of calories from the vending machines on each visit and did not lose weight, according to the study results.
In contrast, the 5 individuals who underwent inactive stimulation on the first visit and active transcranial direct current stimulation at the brain target on the second visit consumed an average of 700 fewer calories and lost an average of 0.8 lb on the second visit.
“Previous studies from our lab at the NIDDK in Phoenix observed lower levels of activation in the left dorsolateral prefrontal cortex after a meal in obese compared with lean humans using [positron emission tomography]. This brain region has been linked to behavioral regulation, taste, and reward processing. The prefrontal cortex, and the dorsolateral sectors in particular play an important role in the organization and planning of behavior,” said Dr Gluck.
Therefore, she and her colleagues investigated whether increasing activation in the dorsolateral prefrontal cortex would decrease food and drink intake and lead to weight loss.
“We administered [transcranial direct current stimulation] during 2 different periods and found that the volunteers ate fewer calories from fat and soda and lost more weight during the anodal activating stimulation compared with when they received a non-activating stimulation. The group who received sham stimulation during both sessions showed no differences in food intake or weight change,” Dr Gluck told Endocrinology Advisor.
“Several previous studies have shown decreased craving following [transcranial direct current stimulation], and 1 specifically showed decreased carbohydrate intake. Ours is the first to show these changes in people with obesity and the first to show changes in weight. It is also the first to conduct these procedures in a well-controlled inpatient setting while using an objective measure of ad libitum food intake over a 3-day period.”
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She said these findings have several clinical implications and imply that obesity might be related to neurological differences and lower activation particularly in the brain region that affects reward processing and executive functions, such as decision making and planning.
There are currently no gold-standard, brain-based interventions for obesity and weight loss, according to Dr Gluck, but this new knowledge could inform treatment options. These findings are encouraging, she noted, and they are fueling new studies by her own group as well as others.
“We currently have a larger study in progress examining food intake and weight loss using anodal compared to sham stimulation in people with obesity. We also plan to explore changes in executive functions before and after stimulation by using a battery of computerized neuropsychological tests. The device used to administer [transcranial direct current stimulation] is modular, and if future studies show promising results, this technique could be used outside of a medical setting,” said Dr Gluck.
- Gluck ME. Obesity Journal Symposium. Noninvasive Neuromodulation Targeted to the Lateral Prefrontal Cortex Induces Changes in Energy Intake and Weight Loss in Obesity. Presented at ObesityWeek; November 2-6, 2015; Los Angeles, CA.
- Gluck ME, Alonso-Alonso-M, Piaggi P, et al. Neuromodulation targeted to the prefrontal cortex induces changes in energy intake and weight loss in obesity. Obesity. 2015;23(11):2149-2156.