eye movement testing in patients with obesity and the impact of weight loss surgery

Conditions: Bariatric Surgery Candidate; Obesity, Morbid

Summary: obesity is a condition of chronic low-grade inflammation, thought to be secondary to adipose tissue secretion of cytokines including interleukin 6 (il-6), and tumor necrosis factor alpha (tnf- α) which effect multiple pathways and lead to an increase in c-reactive protein (crp), a sensitive marker of systemic inflammation. chronic inflammation is thought to be a major risk factor for the development of metabolic syndrome, diabetes, cardiovascular disease and cancer. inflammatory cytokines have also been shown to directly and indirectly interact with the central nervous system influencing behavior and neural activity. obesity is an independent risk factor for reduced cognitive function including poor attention, executive function and memory. demonstrating improvement in dynamic visual processing following bariatric surgery could expand our understanding of the impact of obesity on central nervous system (cns) function.

this study will involve the utilization of a noninvasive computer application (neurofit) to perform oculometric assessment of dynamic visual processing . eye movements are short latency, voluntary motor behaviors that consist of various aspects including visual motion, pursuit initiation, steady-state tracking, direction tuning, and speed tuning. the computer application is based on an eye movement methodology that can quantify many aspects of human dynamic visual processing using a noninvasive video-based eye tracking technology with validated oculometric analysis techniques. it captures 8 domains of oculometric function and reports a composite score (nfit). prior studies have demonstrated sensorimotor dysfunction in patients with diffuse brain injury which leads to derangement in information processing throughout the brain. this computer application has been utilized in patients with traumatic brain injury (tbi). liston et al, in a study of 34 tbi patients, demonstrated that tbi patients had several individual oculometrics that were significantly deranged including pursuit latency, initial pursuit acceleration, pursuit gain, catch-up saccade amplitude, proportion smooth tracking, and speed responsiveness. by comparing individual and composite oculometric data between patients before and after weight-loss surgery, this research study hopes to identify any significant differences or distinct patterns that may exist as a result of obesity. we also intend to compare changes in high-sensitivity crp to assess if post-surgical changes in this inflammatory marker correlates with improvement in dynamic visual processing. patients seen in our bariatric surgery clinic are primarily offered roux-en-y gastric bypass (rygb) and sleeve gastrectomy (sg) as surgical weight loss options. these two procedures are different in that while both provide significant weight loss, the hormonal effects are different between procedures. for this reason, patients undergoing both surgeries will be recruited to determine any differences in oculometrics and serum biomarkers by surgery type. liver histology data will be obtained per chart review if previously available. this data will be used to ascertain the existence of fatty liver disease, steatohepatitis and/or cirrhosis.

Eligibility criteria:
inclusion criteria: * patients who are overweight or obese (body mass index over 25 and 30, respectively) exclusion criteria: * individuals \<18 years * patients with history of cognitive brain disease including traumatic brain injury, dementia, parkinson's disease * individuals with uncontrolled neuropsychiatric illnesses or overt hepatic encephalopathy * ongoing alcohol or illicit substance use * patients with cirrhosis

Keywords: oculometrics