Obesity
Conditions
Keywords
Obesity, Gastric Banding, Transcranial Direct Current Stimulation
Brief summary
In this project the investigators aim to improve eating control and weight loss outcomes in patients undergoing LAGB with an innovative brain-based intervention. Specifically, the investigators will enhance the activity of the right inferior frontal gyrus, a core region of the brain circuit of inhibitory control, using transcranial direct current stimulation (tDCS).
Detailed description
Laparoscopic Adjustable Gastric Banding (LAGB) is a minimally invasive and reversible procedure in bariatric surgery that has a good safety record. Despite these advantages, success rates following LAGB are quite variable across individuals. Recent data suggest that complementing LAGB with interventions targeting factors along the brain-behavior spectrum could enhance weight loss results following this procedure. The study will have the following three aims: Aim #1: To evaluate whether enhancement of the right inferior frontal gyrus with tDCS in patients undergoing LAGB can improve inhibitory control capacity. For this aim the investigators will evaluate participants' performance in a computerized test of inhibitory control. Results from this aim will provide evidence for target engagement, and thus confirm that the brain circuit of interest was affected as a result of the intervention. Aim #2: To examine whether enhancement of the right inferior frontal gyrus with tDCS in patients undergoing LAGB can lead to improvements in a self-reported measure of eating control (disinhibition subscale of the three-factor eating questionnaire). Results form this aim will provide evidence for an effect of the intervention on an intermediate, behavioral variable. Aim #3: To preliminary evaluate whether enhancement of the right inferior frontal gyrus with tDCS in patients undergoing LAGB can improve postoperative weight loss outcomes. This aim will provide preliminary evidence for the clinical efficacy of the intervention over a time window period of 12 months. Weight loss at 12 months will be the primary outcome of the study.
Interventions
DEVICETranscranial Direct Current Stimulation (tDCS)
tDCS is a well-established, safe and noninvasive neuromodulation technique that is based on the application of a weak direct current to the scalp that flows between two electrodes-anode and cathode. Although there is substantial shunting of current in the scalp, sufficient current penetrates the brain to modify the transmembrane neuronal potential, and thus influence the level of excitability and modulate the firing rate of individual neurons. In this study, participants will receive 10 daily sessions of tDCS (sham/real) over a period of two weeks.
Sponsors
Boston Medical Center
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Beth Israel Deaconess Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Investigator)
Eligibility
Sex/Gender
ALL
Age
20 Years to 55 Years
Healthy volunteers
No
Inclusion criteria
* Age: 20-55 years old * BMI: 35-60 kg/m2 * Planning to undergo or having undergone laparoscopic adjustable gastric banding (LAGB) within the previous week
Exclusion criteria
* Unstable medical conditions including poorly controlled diabetes and hypertension * Pregnancy or planning pregnancy during study period * Personal or family history of epilepsy or other unexplained loss of consciousness * Current or past medical history of skin disease or damaged skin on the scalp at site of stimulation * Active psychiatric or neurological condition * Prior neurological procedure * Implanted pacemaker, medication pump, vagal stimulator, deep brain stimulator, TENS unit, or ventriculoperitoneal shunt * Intake of common medications that affect the central nervous system will be allowed if determined okay by MD
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Weight Change | Baseline, 2 weeks after surgery, 10 days of tDCS, 1 month, 3 months, 6 months and 12 months follow up | Participants will be weighed at the indicated time points. Weight loss at 12 months will be the primary outcome of the study. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Eating Disinhibition as Measured by the Three Factor Eating Questionnaire (TFEQ) | Baseline and 12 months follow up | Eating Disinhibition is an eating behavior trait that reflects a tendency towards overeating and eating opportunistically in an obesogenic environment. Examples include eating in response to negative affect, overeating when others are eating, not being able to resist temptations to eat, and overeating in response to the palatability of food (Bryant, King and Blundell. Obes Rev. 2008;9:409-19). Eating disinhibition was measured using the Three Factor Eating Questionnaire (TFEQ), which contains 16 questions for this factor. Responses are scored 0 or 1 and summed, thus eating disinhibition score ranges from 0 to 16. Higher scores denote higher levels of eating disinhibition. |
| Change From Baseline in Inhibitory Control Over Food as Measured by the Stop Signal Reaction Task | 12 month follow-up vs. Baseline | Inhibitory control over food was measured with a Stop Signal Task that was modified with the presence of distractors of two types: images of food and neutral images (control). The Stop Signal Task is a computerized task that evaluates an individual's ability to interrupt a motor response after its initiation (Logan 1994). Subjects were asked to press a response key matching the direction of an arrow, but refrain from pressing when an auditory cue (stop signal) appeared (25% trials). The main outcome of the task is the Stop-Signal-Reaction-Time (SSRT), in milliseconds, which reflects how long it takes to inhibit a response when a stop signal appears. The SSRT is considered a laboratory measure of inhibitory control capacity. Shorter SSRT reflects more efficient inhibitory control. Here a reduction of SSRT from baseline to 12 months indicates improvement in inhibitory capacity. We provide SSRT changes for food and neutral images, reflecting specific and general effects, respectively. |
Countries
United States
Participant flow
Recruitment details
Participants were recruited between June 2012 and July 2014 from the Weight Loss Surgery Center at Beth Israel Deaconess Medical Center.
Pre-assignment details
2 participants withdrew from the study after enrollment but prior to assignment to a treatment arm.
Participants by arm
| Arm | Count |
|---|---|
| Active tDCS In this arm, participants received 10 daily sessions of active Transcranial Direct Current Stimulation (2mA, 20 min per session) over the course of two weeks. The anode electrode was placed over the right inferior frontal gyrus, defined as F8 (10-20 EEG system), with the cathode electrode placed over the contralateral supraorbital area, above the left eyebrow. During each session participants performed a computerized task designed to engage the inhibitory control circuit when confronted with food stimuli. | 6 |
| Sham tDCS In this arm, participants received 10 daily sessions of sham Transcranial Direct Current Sitmulation with the same duration and electrode montage as in the real tDCS arm (20 minutes, targeting the right inferior frontal gyrus). In this case, current was applied for 30 s only according to standard procedures, and participants performed a control task during which they observed and provided responses for the same food and non-food pictures as in the active group task, but without the requirement of inhibitory control for performance. | 6 |
| Total | 12 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Withdrawal by Subject | 1 | 0 |
Baseline characteristics
| Characteristic | Active tDCS | Sham tDCS | Total |
|---|---|---|---|
| Age, Continuous | 42.3 years STANDARD_DEVIATION 8 | 44.3 years STANDARD_DEVIATION 7.1 | 43.3 years STANDARD_DEVIATION 7.3 |
| Sex: Female, Male Female | 4 Participants | 4 Participants | 8 Participants |
| Sex: Female, Male Male | 2 Participants | 2 Participants | 4 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 6 | 0 / 6 |
| other Total, other adverse events | 6 / 6 | 6 / 6 |
| serious Total, serious adverse events | 0 / 6 | 0 / 6 |
Outcome results
Primary
Weight Change
Participants will be weighed at the indicated time points. Weight loss at 12 months will be the primary outcome of the study.
Time frame: Baseline, 2 weeks after surgery, 10 days of tDCS, 1 month, 3 months, 6 months and 12 months follow up
Population: 1 Participant withdrew prior to obtaining outcome data at the 10th day of tDCS, 1 participant was lost to follow-up prior to the 3-month follow-up visit, and 1 participants were lost to follow-up prior to obtaining outcome data at the 6-month follow-up visit.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Active tDCS | Weight Change | 10th day of tDCS | 280.4 pounds (lbs) | Standard Deviation 62.1 |
| Active tDCS | Weight Change | 3 month follow-up | 268 pounds (lbs) | Standard Deviation 52.1 |
| Active tDCS | Weight Change | 2 weeks post gastric band (LAGB) surgery | 273.4 pounds (lbs) | Standard Deviation 62.7 |
| Active tDCS | Weight Change | 6 month follow-up | 278.05 pounds (lbs) | Standard Deviation 52.5 |
| Active tDCS | Weight Change | 1 month follow-up | 273.4 pounds (lbs) | Standard Deviation 57 |
| Active tDCS | Weight Change | 12 month follow-up | 289.8 pounds (lbs) | Standard Deviation 58.8 |
| Active tDCS | Weight Change | Baseline | 285.0 pounds (lbs) | Standard Deviation 63.8 |
| Sham tDCS | Weight Change | 12 month follow-up | 204.2 pounds (lbs) | Standard Deviation 30.5 |
| Sham tDCS | Weight Change | Baseline | 245.3 pounds (lbs) | Standard Deviation 41 |
| Sham tDCS | Weight Change | 2 weeks post gastric band (LAGB) surgery | 228.4 pounds (lbs) | Standard Deviation 34.8 |
| Sham tDCS | Weight Change | 10th day of tDCS | 225.8 pounds (lbs) | Standard Deviation 34 |
| Sham tDCS | Weight Change | 1 month follow-up | 220.3 pounds (lbs) | Standard Deviation 34.1 |
| Sham tDCS | Weight Change | 3 month follow-up | 210.6 pounds (lbs) | Standard Deviation 34.9 |
| Sham tDCS | Weight Change | 6 month follow-up | 206.5 pounds (lbs) | Standard Deviation 31 |
Secondary
Change From Baseline in Inhibitory Control Over Food as Measured by the Stop Signal Reaction Task
Inhibitory control over food was measured with a Stop Signal Task that was modified with the presence of distractors of two types: images of food and neutral images (control). The Stop Signal Task is a computerized task that evaluates an individual's ability to interrupt a motor response after its initiation (Logan 1994). Subjects were asked to press a response key matching the direction of an arrow, but refrain from pressing when an auditory cue (stop signal) appeared (25% trials). The main outcome of the task is the Stop-Signal-Reaction-Time (SSRT), in milliseconds, which reflects how long it takes to inhibit a response when a stop signal appears. The SSRT is considered a laboratory measure of inhibitory control capacity. Shorter SSRT reflects more efficient inhibitory control. Here a reduction of SSRT from baseline to 12 months indicates improvement in inhibitory capacity. We provide SSRT changes for food and neutral images, reflecting specific and general effects, respectively.
Time frame: 12 month follow-up vs. Baseline
Population: 1 participant withdrew prior to the 12 month follow-up and 2 participants were lost to follow-up prior to the 12 month follow-up.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Active tDCS | Change From Baseline in Inhibitory Control Over Food as Measured by the Stop Signal Reaction Task | Change, stop signal reaction time, food images | -72.6 milliseconds (ms) | Standard Deviation 68.3 |
| Active tDCS | Change From Baseline in Inhibitory Control Over Food as Measured by the Stop Signal Reaction Task | Change, stop signal reaction time, neutral images | -62.3 milliseconds (ms) | Standard Deviation 77.8 |
| Sham tDCS | Change From Baseline in Inhibitory Control Over Food as Measured by the Stop Signal Reaction Task | Change, stop signal reaction time, food images | -51.1 milliseconds (ms) | Standard Deviation 49.8 |
| Sham tDCS | Change From Baseline in Inhibitory Control Over Food as Measured by the Stop Signal Reaction Task | Change, stop signal reaction time, neutral images | -46.4 milliseconds (ms) | Standard Deviation 67.7 |
Secondary
Eating Disinhibition as Measured by the Three Factor Eating Questionnaire (TFEQ)
Eating Disinhibition is an eating behavior trait that reflects a tendency towards overeating and eating opportunistically in an obesogenic environment. Examples include eating in response to negative affect, overeating when others are eating, not being able to resist temptations to eat, and overeating in response to the palatability of food (Bryant, King and Blundell. Obes Rev. 2008;9:409-19). Eating disinhibition was measured using the Three Factor Eating Questionnaire (TFEQ), which contains 16 questions for this factor. Responses are scored 0 or 1 and summed, thus eating disinhibition score ranges from 0 to 16. Higher scores denote higher levels of eating disinhibition.
Time frame: Baseline and 12 months follow up
Population: 1 participant withdrew prior to the 12 month follow-up and 2 participants were lost to follow-up prior to the 12 month follow-up.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Active tDCS | Eating Disinhibition as Measured by the Three Factor Eating Questionnaire (TFEQ) | Baseline | 7.0 units on a scale | Standard Deviation 5.4 |
| Active tDCS | Eating Disinhibition as Measured by the Three Factor Eating Questionnaire (TFEQ) | 12 month follow-up | 5.0 units on a scale | Standard Deviation 1.2 |
| Sham tDCS | Eating Disinhibition as Measured by the Three Factor Eating Questionnaire (TFEQ) | Baseline | 3.8 units on a scale | Standard Deviation 2.1 |
| Sham tDCS | Eating Disinhibition as Measured by the Three Factor Eating Questionnaire (TFEQ) | 12 month follow-up | 3.6 units on a scale | Standard Deviation 4.2 |