2 September 2020
Using CANTAB to study the relationships between executive function, eating behaviour and preoperative weight loss in bariatric surgery candidates
PhD candidate Gro Walø-Syversen of Oslo University Hospital, shared the role that CANTAB played in her latest publication: Executive Function, Eating Behavior, and Preoperative Weight Loss in Bariatric Surgery Candidates: An Observational Study.
PhD Gro Walø-Syversen has a position in Oslo Bariatric Surgery Study Cognitive (OBSSC) which is a research collaboration between the Regional Department of Eating Disorders and Centre for Morbid Obesity at Oslo University Hospital and the Psychology Department at the University of Oslo.
Information about yourself
Gro is a licensed psychologist specialized in treatment of addiction disorders. After some years as therapist in the addiction field, she currently has a position as PhD candidate at Oslo University Hospital. The interest in severe obesity, bariatric surgery and weight loss comes from a general curiosity about the individual factors and processes that are involved in the maintenance and change of addiction and other maladaptive behaviour patterns (i.e. loss-of control eating).
Background to the study, the methods used and why
The Oslo Bariatric Surgery Study Cognitive (OBSSC) is an observational research project that overall aims to investigate neuropsychological functioning in relation to weight loss during bariatric surgery. Bariatric surgery is a main treatment option for severe obesity that leads to substantial weight loss and improvement in obesity-related diseases; however a substantial proportion of patients struggle with maintaining their initial weight loss over time . The sustainability of the weight loss requires a permanent life style change, otherwise there is a significant risk of postoperative weight regain. A growing literature indicates that both pre-and postoperative neuropsychological functioning predicts long-term weight loss after surgery. Also, some studies suggest that surgery is followed by improved neuropsychological functioning . The OBSSC project aims to contribute to this growing research field by using a broad selection of cognitive tests from CANTABTM that already have been used in prior studies on severe obesity, behavioral weight loss interventions and laboratory food tasks. Ultimately, we hope the project will provide some insight into the role of cognitive function in surgical weight loss outcomes, and that these insights can lead to increased attention to individuals in need for extended postoperative support to optimize weight loss outcomes.
Summary of your findings and their implications
We are still in the process of analysing the collected data. We have assessed cognitive function with 6 tests from CANTABTM before and after surgery (1- and 2-year follow-up) in a sample (n=80) of Norwegian bariatric surgery patients. They also completed self-report questionnaires on eating behaviours, depression and other psychological factors related to bariatric surgery at each follow-up point. In the first published study we have focused on subcomponents of executive function (working memory and inhibitory control) that predicts preoperative weight loss. A main finding from this study was that working memory (measured by Spatial Working Memory, SMW) accounted for a moderate proportion of variance in preoperative WL . Also, we found that inhibitory control predicted self-reported adherence to the national dietary guidelines. We currently have one report on inhibitory control (Stop Signal Task, SST) and postoperative WL under review, and plan to submit a report on postoperative change in visual memory (Paired Associate Learning, PAL) this summer.
Why did you choose CANTAB for your study?
We feel that CANTABTM offers easy to use, sensitive and reliable cognitive tests that are appropriate for repeat testing. Also, since CANTABTM is widely used in diverse research settings and in clinical populations we have a large base of studies to use as reference for our own findings.
What future areas of investigation could follow your research?
Although this is a huge jump forward in time, I would have enjoyed studying more thoroughly if and how relevant tests could be put to use in everyday clinical practice at the hospital. Is it for instance possible to develop cut-off scores or other indicators of test performance that reliably identify individuals that are in risk for suboptimal weight loss outcomes? If so, these individuals could be selected for augmented postoperative support. Also, it would have been nice to study and identify the factors that mediate the relationships between cognitive function and postoperative weight loss.
Anything else you'd like to share?
In administering particularly SST, we realized how extremely important it was to repeatedly emphasize to the participants how the tests was built, i.e. that SST is made to produce errors a lot of the time, in order to avoid that the participants was left with a negative evaluation of themselves after testing. Also, we were quite impressed over the participants` ability to stay on track and keep up their motivation in spite of a long-lasting test battery.
1. Chang, S., et al., The effectiveness and risks of bariatric surgery: An updated systematic review and meta-analysis, 2003-2012. JAMA Surgery, 2014. 149(3): p. 275-287.
2. Spitznagel, M.B., et al., Neurocognitive Effects of Obesity and Bariatric Surgery. European Eating Disorders Review, 2015. 23(6): p. 488-495.
3. Walø-Syversen, G., et al., Executive Function, Eating Behavior, and Preoperative Weight Loss in Bariatric Surgery Candidates: An Observational Study. Obesity Facts, 2019.
Gro Walø-Syversen, Regional Department of Eating Disorders - Oslo University Hospital.