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 they 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.

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.

• Obesity
• Weight Loss

• Behavioral: Behavioral Weight Loss Treatment
• Procedure: Transcranial Direct Current Stimulation (TDCS)
• Device: Transcranial Direct Current Stimulation (TDCS)
• Behavioral: Appetite Control
• Procedure: Appetite Control
• Device: Weight Control
• Behavioral: Weight Loss

• Caballero B. Introduction. Symposium: Obesity in developing countries: biological and ecological factors. J Nutr. 2001 Mar;131(3):866S-870S. Review.
• Flegal KM, Carroll MD, Ogden CL, Johnson CL. Prevalence and trends in obesity among US adults, 1999-2000. JAMA. 2002 Oct 9;288(14):1723-7.
• Chowdhury U, Lask B. Clinical implications of brain imaging in eating disorders. Psychiatr Clin North Am. 2001 Jun;24(2):227-34. Review.

• INCLUSION CRITERIA:
• BMI greater than or equal to 35 kg/m(2), with at least 2 previous failed weight loss attempts
• Age 18-60 years. Women who are post-menopausal will be excluded from the study due to changes in their metabolism that could affect weight loss. We will set the cutoff at age 60 so that the age difference between the men and women is not too great for analysis purposes. Minors under the age of 18 will be excluded because the time requirements of the study are such that they would interfere with school schedules. Additionally, while the risks of TDCS are minimal, there haven't been studies showing how TDCS might affect the growing brain.
• Healthy, as determined by medical history, physical examination, and laboratory tests
• Right-handedness (because the treatment will be given to the left dorsolateral prefrontal cortex and the evidence accumulated in this region was only in right-handed individuals)
• Weight stable (plus or minus 5 percent) for last 3 months

EXCLUSION CRITERIA:

• Weight less than 350 lbs, as this is the weight limit of the DXA machine
• Type 2 diabetes (according to the World Health Organization diagnostic criteria)
• Endocrine disorders (Cushing's disease, pituitary disorders, and hypo- and hyperthyroidism)
• Chronic pulmonary disorders, including chronic obstructive pulmonary disease that would limit ability to follow the protocol (investigator judgment) and obstructive sleep apnea syndrome; only subjects with mild or exercise-induced asthma on no medications or on beta-adrenergic agonists only (such as albuterol) will be allowed to enter the study (provided use of these agents is not required for 1 week before study entry).
• Cardiovascular diseases (coronary heart disease, heart failure, arrhythmias, and peripheral artery disease)
• Hypertension (blood pressure measurement higher than 140/90 mmHg on 2 or more occasions or use of anti-hypertensive medications)
• Diagnosed gastrointestinal diseases, including inflammatory bowel diseases (e.g. Crohn's disease and ulcerative colitis), malabsorption syndromes (e.g. celiac disease), gastric ulcer (active); only subjects with gastro-esophageal reflux will be allowed to enter the study
• Liver disease (cirrhosis, active hepatitis B or C, and AST or ALT greater than or equal to 1.5 times normal)
• Renal disease (serum creatinine concentrations greater than or equal to 1.5 mg/dl and/or overt proteinuria)
• Central nervous system disease (cerebrovascular accidents, dementia, neurodegenerative disorders, epilepsy or history of head injury). Personal or first-degree relative with a seizure history.
• Cancer requiring treatment in the past 5 years, except for non-melanoma skin cancers or cancers that have clearly been cured or, in the opinion of the investigator, carry an excellent prognosis (e.g., Stage 1 cervical cancer)
• Alcohol (more than 3 drinks per day) and/or drug abuse (such as amphetamines, cocaine, heroin, or marijuana)
• Smoking more than 5 cigarettes per day
• Current psychiatric disorder, as diagnosed by the Structured Clinical Interview for DSM-IV-R. Those who report suicidal ideation or clinically significant problems will be immediately referred for appropriate treatment.
• Presence of metal in the cranial cavity
• Holes in the skull made by trauma or surgery
• Pregnancy or lactation. All women (who could bear children) not using a medically approved method of contraception (surgical sterilization, intrauterine device, or a combined method using at least 2 of the following: diaphragm, condom, spermicide) will be excluded.
• Postmenopausal women or symptoms of perimenopause (e.g. hot flashes, onset of irregular periods following age 40, elevation of FSH greater than 20 IU following age 40 years)
• Taking weight loss medications or psychotropic medication
• History of HIV infection or ongoing chronic infection (such as tuberculosis)
• Conditions not specifically mentioned above may serve as criteria for exclusion at the discretion of the investigators