Noninvasive Neuromodulation of the Prefrontal Cortex in Subjects With Obesity
Condition: Obesity
MeSH terms: Obesity
Study type: Interventional

Summary: 
      The overall goal of this proposal is to evaluate the efficacy of transcranial direct current
      stimulation (tDCS), a noninvasive neuromodulation technique, to facilitate weight loss and
      weight loss maintenance in obesity. This is a novel clinical research study that examines the
      therapeutic potential of an innovative biomedical treatment for weight loss.
    

Detailed description: 
      The hypothesis is that tDCS will successfully engage prefrontal-related neurobehavioral
      cognitive control systems, resulting in decreased eating disinhibition and therefore
      facilitation of weight loss and weight loss maintenance. To test this hypothesis, a 6-month
      randomized, sham-controlled, double-blind, intervention study was designed. Subjects will
      undergo an intervention with the following components/phases:

        1. Phase 1 - Target engagement (one session) The purpose of this phase is to examine
           whether tDCS can reach the brain target, the dorsolateral prefrontal cortex, and
           influence performance in a neuropsychology tests that depends on the activity of this
           region. Results from this component of the study will provide evidence for target
           engagement. Genomic DNA will be extracted from whole blood for sequencing of
           Catechol-O-methyltransferase (COMT) and brain-derived neurotrophic factor (BDNF)
           polymorphism genotypes.

        2. Phase 2 - tDCS alone (two weeks) During this phase participants will receive daily tDCS
           sessions over the course of two weeks (Monday to Friday; total=10 sessions). The purpose
           of this phase is to examine the effect of modulating the activity of the prefrontal
           cortex with tDCS on body weight under baseline/weight stable conditions. Also analyse
           changes in appetite and eating behavior.

        3. Phase 3 - tDCS plus hypocaloric diet (two weeks). During this phase participants will
           undergo a hypocaloric diet intervention aimed at achieving a 5% body weight reduction at
           3 months. The diet will be individualized on the basis of physical activity levels, age
           for each participant. This intervention will be be conducted at an inpatient,
           well-controlled setting to guarantee adherence to the diet. Here the diet intervention
           will be administered in combination with tDCS. tDCS will be applied every other day
           (Monday, Wednesday, Friday) over the course of these two weeks. The purpose of this
           component is to examine acute changes in weight associated with tDCS in combination with
           the diet. Also analyse changes in appetite and eating behavior.

        4. Phase 4 - Follow up (6 months). During this phase (outpatient) changes in body weight
           over time will be assessed to evaluate weight maintenance. Subjects will be asked to
           come back to the laboratory at 1, 3 and 6 months. Also analyse changes in appetite and
           eating behavior.
    

Intervention name(s): Active transcranial direct current stimulation (tDCS); Hypocaloric diet; Sham transcranial direct current stimulation (tDCS)
Intervention type(s): Device; Other; Other
Intervention description(s): Participants will receive 10 daily sessions (phase 2) and 3 times a week (phase 3) of tDCS (2mA, 30 min per session). The tDCS montage will target the left dorsolateral prefrontal cortex (DLPFC) (anode: F3 based on the 10:20 system; cathode over the right supraorbital area). For stimulation the investigators will use 5x5cm sponge pads that will be soaked in 0.9% saline during the sessions.; During phase 3, participants will undergo a supervised hypocaloric diet intervention for 2 weeks based on a low-calorie diet (LCD) providing a hypocaloric diet based in 20% reduction from total energy expenditure (TEE). The diet will be individualized on the basis of physical activity levels, age for each participant. This intervention will be be conducted at an inpatient, well-controlled setting to guarantee adherence to the diet. Here the diet intervention will be administered in combination with tDCS. tDCS will be applied every other day (Monday, Wednesday, Friday) over the course of these two weeks.; Subjects in the control group will receive sham stimulation (placebo) (similar procedure and duration as real tDCS, but here electric current flows for 30 s only, to mimic the subjective sensations that occur with active tDCS).
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: Obesity; Feeding behavior; Transcranial direct current stimulation; Weight loss