This study will determine whether electrical stimulation of an area of the brain called the dorsolateral prefrontal cortex, which is important in determining the feeling of fullness after eating, affects how much food a person eats and weight loss over 4 weeks. It will also compare weight changes in people who attend weight loss counseling sessions and those who do not over this period of time.
Obese, non-diabetic people between 18 and 60 years of age who are in good health and who live in the Phoenix, AZ, metropolitan area are eligible for this study. Candidates must have a body mass index of 35 kg/m(2) or more and weigh less than 350 pounds.
Participants are admitted to the NIH inpatient unit in Phoenix for the first 9 days of the study for tests, which include meal tests to determine eating behaviors and caloric intake, blood and urine tests, glucose tolerance test, weight measurement, psychological assessments and DEXA scan to measure body fat. For 3 of the days, they will be asked to eat all of their food from automated vending machines. Some subjects receive transcranial direct current stimulation (TDCS). For this procedure, electrodes that conduct electricity are placed on the head and arm and the current is turned on for 40 minutes. Some tingling may be felt under the electrodes. Other subjects receive sham TDCS, with the current turned on only very briefly.
After the evaluations, subjects are discharged home from the NIH unit and instructed to eat 25 percent fewer calories than they consumed while on a weight maintenance diet the first 3 days of their inpatient stay. They maintain the lower calorie diet at home for 4 weeks. During this period they come to the NIH unit 3 days a week to receive either real or sham TDCS. Some subjects are also assigned to receive weight loss counseling sessions twice a week, while others are not. At the end of the 4 weeks, subjects return to the NIH unit for a 5-day stay to undergo a repeat DEXA scan, meal tests, psychological assessment and blood tests, and will eat for another 3 days from the vending machines.
At the completion of the study, all participants may choose to receive 4 more weeks of TDCS or behavioral weight loss counseling, or both.
Primary Outcome Measures:
- Effects of TCDS on weight loss and appetitie.
Secondary Outcome Measures:
- Effect of behavioral intervention on weight loss.
| Estimated Enrollment: |
82 |
| Study Start Date: |
August 2008 |
Intervention Details:
Behavioral: Behavioral Weight Loss Treatment
N/A
Procedure: Transcranial Direct Current Stimulation (TDCS)
N/A
Device: Transcranial Direct Current Stimulation (TDCS)
N/A
Behavioral: Appetite Control
N/A
Procedure: Appetite Control
N/A
Device: Weight Control
N/A
Behavioral: Weight Loss
N/A
In our studies of brain function examining areas related to hunger and fullness, a part of the brain called the left dorsolateral prefrontal cortex (DLPFC) was found to be less active in obese versus lean individuals following a meal. Furthermore, in women who have lost and maintained weight loss, the activity in this area following a meal is similar to that of lean women, suggesting that the activity in this area may improve with weight loss. Two recent studies have demonstrated a lack of increase in food craving following non-invasive brain stimulation to the left DLPFC when compared to a sham control group that did not receive brain stimulation.
The aim of the current study is to investigate the effectiveness of one type of noninvasive brain stimulation technique, transcranial direct current stimulation (TDCS) on food intake in 82 significantly overweight (BMI greater than or equal to 35 kg/m(2)) individuals. TDCS alters the environment in the brain in a way that may promote learning, thus a second aim of this study is to investigate if TDCS over the left DLPFC enhances performance in a behavioral weight loss program.
This will be a double-blind parallel study with four arms: TDCS plus behavioral weight loss counseling; no stimulation (sham) plus counseling; TDCS plus no behavioral weight loss counseling and no stimulation plus no counseling. All four groups will be asked to consume a diet that is a 25 percent reduction from their calculated weight maintenance calories. The primary outcome measurements will be total food intake during 3 days of ad libitum intake from a computerized vending machine system, and weight loss during a 4-week outpatient period. We will also examine appetitive hormones and behavioral factors, which might also mediate potential changes in food intake and weight loss following TDCS to the left DLPFC. Positive findings from this study could demonstrate the utility of a novel and safe treatment for severe obesity. Future studies could include longer clinical trials of TDCS with extended follow-up durations.
Purpose
