Title: Surgery to Reduce Weight May Reverse Negative Cognitive Effects in Obese Teens

Weight-loss surgery may reverse the negative effects of teenage obesity on cognitive functioning, according to a new study by a Georgetown psychology professor.

Research has shown that children with obesity exhibit deficits in cognitive functioning and have lower academic achievement and has also shown thatbariatric surgery has positive effects on health, including insulin regulation.

Georgetown psychology department chair Chandan Vaidya, who conducted the study with doctoral candidate Alaina Pearce (G’16) and a team from Children’s National Health System, wanted to see if such benefits extended to cognitive functioning.

Obesity and the Brain

“Brain functioning is central to this discussion, because when you’re thinking about what might maintain or promote obesity, you’re looking at rewarding behaviors that people cannot control,” said Vaidya, who with the research team conducted the pilot study funded by the National Institute of Diabetes and Digestive and Kidney Diseases. “So we’re looking at places in the brain that are important for self-regulation and processing of rewards.”

The study, the first to explore the effects of weight-loss surgery on the brains of obese adolescents, examined functional changes in adolescent brains after bariatric surgery, which reduces the size of the stomach for weight control.

The prestigious journal Obesity named the resulting paper on the research, “Effect of Adolescent Bariatric Surgery on the Brain and Cognition: A Pilot Study,” an Editor’s Choice in its November issue.

Cognitive Functioning

A total 36 adolescents recruited for the pilot study from the Children’s National Bariatric Surgery program, were split into three groups: A normal-weight control group that did not undergo surgery, a group with obesity that underwent the surgery, and another that has committed to the surgery but had not undergone it yet.

The researchers used functional magnetic resonance imaging to measure brain activity in adolescents in each group as they completed a variety of tasks designed to gauge executive function and anticipation of reward.

“Speed of information processing and accuracy were both better among the group that got the surgery,” said Vaidya, who also holds a $2 million grant from the National Institutes of Health to look at executive functioning in children and adults with psychiatric disorders. “These adolescents also lost nine Body Mass Index points, which is a significant amount of weight loss.”

The fMRI scans also revealed less activity in the prefrontal cortex and striatal regions among these subjects – showing their brains didn’t have to work as hard after weight-loss surgery to complete the same tasks.

Limited Previous Research

“You could think of it as becoming more efficient,” Vaidya said. “The amount of activity decreased after the surgery, to the extent that it looked similar to the healthy control group.” Vaidya says the literature on adolescent post-surgical outcomes is very limited and similar studies in adults only tested cognitive responses to food-related imagery.

“We’re looking at baseline cognitive functions,” she said. “If we show that these change, it’s even more impactful, because it goes beyond just responses to food.”

The Georgetown professor hopes to replicate the team’s findings in a study with a larger group.

“There are also other factors we’d like to explore — better sleep, for example, might be related to both the weight loss and the improvements in neurocognitive functioning,” Vaidya said. “It is also important to know whether these effects translate into better food and activity choices and improved academic functioning in the adolescents.”