Evidence for Neurocognitive Improvement After Bariatric Surgery: A Systematic Review.

BACKGROUND Bariatric surgery is an effective means of weight reduction in severely obese patients and correlates with improvements in quality of life, mental health outcomes, and neurocognition, especially in those with high psychosocial burden. OBJECTIVE The primary purpose of this systematic review was to evaluate the impact of bariatric surgery on long-term neurocognitive functioning and neuropsychological outcomes. METHODS OVID Medline and PsychInfo databases from January 1990 to August 2015 were searched with key terms and phrases: "bariatric surgery" and "cognition." The inclusion criteria for the studies included the following: n ≥ 10, minimum postoperative follow-up of 12 months, and use of formal neurocognitive assessment tools presurgery and postsurgery. RESULTS Of 422 identified abstracts, a total of 10 studies met inclusion criteria and sample sizes ranged from 10-156. Postsurgical follow-up time ranged from 12-36 months. All 10 studies documented significant improvements of statistical significance (p < 0.05) in at least 1 neurocognitive domain following bariatric surgery; 9 studies showed improvements in memory, 4 studies showed improvement in executive function, and 2 studies showed improvements in language, and 1 study showed no improvement in any neurocognitive domain. CONCLUSION Mental health care providers should consider the effect of neurocognitive performance on presurgery psychiatric assessments for bariatric surgery and implications for psychosocial functioning postsurgery. The aforementioned effect that bariatric surgical intervention has on neurocognition underscores the complex interrelationship between metabolism and brain function. Future research should validate the use of neurocognitive screening tools presurgery and evaluate the impact of neurocognitive changes on neurocognitive, bariatric, and functional outcomes.