Preliminary Feasibility of an Interdisciplinary Study Identifying Predictors of Success in Bariatric Surgery: Neuroimaging Meets Surgical Weight Loss

Kasey O’Neil, BS, Janet Ng, PhD, Darren Tishler, MD, Pavlos Papasavas, MD, Beth Anderson, PhD, Hedy Kober, PhD, Haley Yarosh, PhD, Rebecca Boswell, BA, Andrea Stone, BA, Glenn Treisman, MD, Godfrey Pearlson, MD, PhD. Olin Neuropsychiatry Research Center, Hartford Hospital Surgical Weight Loss Center, Yale University, John Hopkins University.

Obesity is a leading public health concern in the US. As the rate of morbid obesity rises, bariatric surgery is becoming an increasingly important treatment modality for individuals who struggle with weight loss. Continued follow-up, regular exercise and healthier diet are common post-surgical predictors of successful weight loss, but currently there are no pre-surgical behaviors that are putative predictors of success after bariatric surgery. This project aims to explore evidence for the hypothesis that failure to lose significant weight by 12 months post-bariatric surgery is related to features of “food addiction”. By using fMRI tasks and behavioral measures we hope to prospectively identify characteristics that will predict successful versus unsuccessful surgical outcome.

Methods/ design:
The study is collecting neuroimaging data on 100 obese adults (18-60 years) approximately 4 weeks before undergoing laparoscopic adjustable gastric banding (LAGB), RYGB and sleeve gastrectomy surgical procedures and again 12 months post-operatively. Neuroimaging tasks focus on the circuits underlying impulsivity, reward, emotional and cognitive control, previously shown to have a strong influence in other addictive behaviors. Blood work is also collected to investigate hormonal influence regulating hunger and satiety. Routine post-operative follow-up measures and self-report measures on mood, weight and eating behaviors, anxiety, stress and life events are assessed monthly.

To date participants were 29 obese (BMI =45.9, SD=8.3) and 4 community control (mean BMI=23.3, SD=1.7) adults (23 women; mean age=41.5 years, SD 11.7). Participants completed 3 hours of fMRI scanning over two sessions. Tasks ranged from 10-30 minutes assessing: impulsivity (Go/No Go, monetary incentive delay), mood regulation (affective pictures task), cognitive control (regulation of craving) and reward function (anticipatory food cues versus receipt/consumption of food). Four participants were unable to tolerate imaging sessions due to claustrophobia.

The study will provide critical information about the relation between neurobiological functioning, behavioral assessments, and bariatric surgery outcome. We discuss the initial challenges faced in organizing a large neuroimaging study with bariatric participants: MRI physical limitations, MRI-task considerations, and recruitment feasibility. The results of this study will provide a comprehensive examination of bariatric surgery predictors and will further our understanding of how various factors (individual, hormonal, behavioral, cognitive, emotional) interact to influence weight loss. In addition to identifying predictors of success in the total participant sample, the study aims to compare success across bariatric surgery type (LAGB, RYGB, sleeve gastrectomy).

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