About this trial
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.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
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
Disqualifiers
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.
Trial design
Parallel
Treatments tested in this trial
home-based tDCS stimulation
Devicestimulation 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)
home-based tDCS stimulation - sham
Device20 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.
Bariatric surgery
Procedure/SurgeryThe 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.
Treatment groups
Trial outcomes
Primary outcomes
Cognitive impulse control measured via food-modified Go/No-Go task
The cognitive task is used to assess response inhibition, particularly in the context of food-related stimuli. It is a variation of the standard Go/No-Go task, where participants must respond quickly to "Go" stimuli (low-calorie item) while withholding responses to "No-Go" stimuli (high-calorie item). Researchers analyze reaction times, accuracy, and commission errors (responses to No-Go stimuli) to evaluate impulse control.
Secondary outcomes
Brain activation related to cognitive control assessed using a multichannel EEG system
The investigators will evaluate brain activity in response to food-modified Go/No-Go stimuli and during rest, using Time-Frequency Analysis, focusing on theta and beta power.
Body bioimpedance analysis measured with the InBody 720 device
Patients, wearing light clothing and standing barefoot with their legs slightly apart, will hold the device's sensors. Within seconds, the device calculates parameters such as total body water, fat mass, muscle mass, and segmental composition.
Food craving of patients assessed using Food Craving Questionnaire - Trait
The questionnaire has 21 items with a response scale 1-6, higher score means stronger cravings.
Eating habits of patients assessed using the Three-Factor Eating Questionnaire
The Questionnaire has 51 items in total, 36 items ask for true/false judgment, and 15 items are scored on a 4-point Likert-type scale, each item scores either 0 or 1 point, the minimum score for factors Cognitive Restraint, Disinhibition, and Hunger is 0-0-0, the possible maximum score is 21-16-14.
Sponsors and contacts
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Masaryk University
Lead sponsor
St. Anne's University Hospital Brno, Czech Republic
Collaborator