Non-invasive Brain Stimulation to Prepare the Patient for Bariatric Surgery (REBAS)

Official title

Non-invasive Brain Stimulation to Prepare the Patient for Bariatric Surgery

Overview

Obesity is a chronic metabolic condition characterized by excessive accumulation of body fat, which triggers physiological mechanisms that increase the risk of a wide range of health problems. The most effective treatment for severe obesity is metabolic-bariatric surgery, which can lead to a 15-20% weight reduction, significantly lowering the risks of illness and death. However, the success of this surgery can be threatened by poor eating habits after the procedure. The main goal of this study is to enhance the long-term effectiveness of bariatric surgery by combining it with non-invasive brain stimulation (tDCS) targeting inhibitory centers before the operation. Additionally, the investigators aim to comprehensively monitor patients before and after surgery, focusing on investigating changes in brain function associated with the achieved weight loss.

Detailed description

Obesity, defined as a body mass index (BMI) above 30 kg/m² or through other body composition measurements like waist circumference or body fat percentage, is a major risk factor for cardiovascular, neurological, and oncological diseases. It is one of the leading causes of mortality in both men and women. The prevalence of obesity is increasing globally, particularly among younger populations, surpassing undernutrition and posing significant health and socio-economic challenges.

Excess fat accumulation, a hallmark of obesity, impacts the structure and function of nearly all organ systems. This occurs through both physical mechanisms, such as fat deposition around organs, and functional mechanisms, including chronic low-grade inflammation, insulin resistance, dyslipidemia, and altered hormone production and regulation by adipose tissue.

While various therapies have been developed to address the negative effects of obesity on body structure and function, early interventions like lifestyle changes and pharmacotherapy have shown only mild and often temporary weight reduction. These approaches frequently lead to cyclical weight changes, which have been linked to increased cardiovascular risk.

Bariatric surgery has emerged as the most effective treatment for severe obesity, delivering significant and long-lasting weight reduction compared to lifestyle modifications. While lifestyle interventions typically achieve a weight loss of 5-10%, bariatric surgery can result in reductions of 15-20%. However, a notable challenge is the risk of failure, primarily due to noncompliant eating behaviors after surgery. Approximately 40% of individuals with extreme obesity are at high risk of experiencing suboptimal outcomes following bariatric surgery.

To address this issue, our project aims to improve the sustainability of bariatric surgery outcomes by incorporating neuromodulation before the procedure. Specifically, the investigators propose using transcranial direct current stimulation (tDCS) to enhance prefrontal inhibitory control by targeting the left dorsolateral prefrontal cortex (lDLPFC). This home-based, non-invasive brain stimulation method seeks to improve behavioral regulation, potentially reducing the likelihood of postoperative complications related to eating habits.

Additionally, researchers aim to identify neural, cognitive, and behavioral predictors of successful bariatric surgery outcomes. By examining these factors, investigators plan to optimize treatment strategies, ensuring more effective and sustainable results for individuals undergoing bariatric surgery.

Interventions

• Device home-based tDCS stimulation
  stimulation parameters: 20 sessions of tDCS over lDLPFC (anode over F3, based on the 10:20 system, and cathode over the right supraorbital area), 2 mA intensity, 20 min duration (30 s fade in/fade out)
• Device home-based tDCS stimulation - sham
  20 sessions of tDCS over lDLPFC (anode over F3, based on the 10:20 system, and cathode over the right supraorbital area), the electric current will flow for only 15 s, with similar fade in/fade out, at the beginning and at the end of 20 min, to mimic the subjective sensations that occur during active tDCS.
• Procedure Bariatric surgery
  The operation itself is not a study-related procedure and thus the indicated patients would undergo the surgery regardless of their participation in this study. The operating surgeons will perform either Roux-en-Y or gastric sleeve resection.

Primary outcome measures

• Cognitive impulse control measured via food-modified Go/No-Go task [Time frame: Baseline, 1 month and 6 months.]

Secondary outcome measures (4)

• Brain activation related to cognitive control assessed using a multichannel EEG system [Time frame: Baseline, 1 month and 6 months.]
• Body bioimpedance analysis measured with the InBody 720 device [Time frame: Baseline, 1 month and 6 months.]
• Food craving of patients assessed using Food Craving Questionnaire - Trait [Time frame: Baseline, 1 month and 6 months.]
• Eating habits of patients assessed using the Three-Factor Eating Questionnaire [Time frame: Baseline, 1 month and 6 months.]

Eligibility criteria

Inclusion criteria

• Subjects with severe or morbid obesity (determined by BMI > 35 or 40 kg/m2, respectively) eligible for BS treatment in compliance with the current guidelines
• Subjects who meet reduced control over eating behavior (disinhibition) criteria in the Eating Habits Questionnaire

Exclusion criteria

• Subjects unable to provide informed consent and those unable to understand and cooperate with study-related procedures (based on the physician's discretion)
• Subjects with a personal history of ischemic heart disease, myocardial infarction, stroke, heart failure, and atrial fibrillation
• Subjects who have already undergone BS treatment in the past
• Pregnant subjects or subjects that plan on becoming pregnant during the study.
• Subjects deemed unsuitable for the study based on expert evaluation (e.g., by a physician or neuropsychologist) will be excluded.
• Subjects with dreadlocks (problematic for the EEG)

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Quadruple blind

Primary purpose

Supportive care

Study locations

Czechia · 2 centers

• Saint Anne's University Hospital — Brno
• Central European Institute of Technology Masaryk University — Brno

Identifiers

NCT: NCT06874309 · NW24-04-00392

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗