Obesity affects the whole body, from more obvious physical impacts on bones and joints to more subtle, internal impacts on organs like the brain.
For the first time, a team of researchers has used functional magnetic resonance imaging (fMRI) to capture the brain function of a small population of adolescents with obesity, both before and after bariatric surgery. The goal is to better understand the neural changes that occur when an adolescent is obese, and determine the effectiveness of interventions, such as vertical sleeve gastrectomy, at improving brain function as weight is lost.
The study, published as the November Editors’ Choice in the journal Obesity, found that executive and reward-related brain functions of study participants with obesity improved following the surgical procedure and initial weight loss.
“We’ve known for some time that severe obesity has negative consequences on some neurocognitive function areas for adults,” says Chandan Vaidya, Ph.D., chair of the Department of Psychology at Georgetown University and a senior author of the study. “But for the first time, we’ve captured fMRI evidence in young patients, and also shown that surgical intervention and the resulting weight loss can reverse some of those deficits.”
“For me, this early evidence makes a strong case that when kids are struggling with severe obesity, we need to consider surgical intervention as an option sooner in the process,” notes Evan Nadler, M.D., director of the Bariatric Surgery Program at Children’s National Health System, who also contributed to the study. “The question that remains is whether the neurocognitive function improves more if surgery, and thus weight loss, happens earlier – and is there a time factor that should help us determine when to perform a procedure that will maximize improvements?”
The preliminary study included 36 participants and was conducted using patients recruited from the Children’s National Bariatric Surgery program, one of the first children’s hospitals to achieve national accreditation by the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program.
“We asked these questions because we know that in the kids we see, their behavioral, brain, and physical health are all very closely related to one another and have an impact on each other,” adds Eleanor Mackey, Ph.D., study senior author and co-principal investigator on the National Institute of Diabetes and Digestive and Kidney Diseases grant that funded the project. “We expected that as physical health improves, we might see corresponding improvements in brain and behavior such as cognitive and school performance.”
The study also pointed out some technical and practical challenges to studying this particular young population. Anyone with a BMI greater than 50 was not able to fit within the MR bore used in the study, preventing fMRI participation by those patients.
“In addition to future studies with a larger sample size, we’d like to see if there are neuroimaging markers of plasticity differences in a population with BMI greater than 50,” says Dr. Vaidya. “Does the severity of the obesity change how quickly the brain can adapt following surgery and weight loss?”
The abstract was selected by the journal’s editors as one that provides insights into preventing and treating obesity. It was featured at the Obesity Journal Symposium during Obesity Week 2017 in Washington, D.C., as part of the Obesity Week recognition, and a digital video abstract was also released about the findings.