Berlin (PRWEB) June 13, 2013
The first use of deep brain stimulation to the brain’s “feeding center” was associated with a weight loss trend in morbidly obese patients, according to a pilot study presented today by Allegheny General Hospital neurosurgeon Michael Oh, MD at the International Neuromodulation Society’s 11th World Congress in Berlin.
The FDA-approved study examined the safety and efficacy of using deep brain stimulation to change activity in lateral hypothalamic area (LHA)—the area of the brain thought to control hunger¬— in three patients who had failed to keep weight off after gastric bypass surgery.
Deep brain stimulation (DBS) is routinely used to control motor symptoms in patients with Parkinson’s disease, dystonia and other movement disorders. Surgeons implant slender leads tipped with electrical contacts into the brain to deliver mild electrical pulses to locations associated with specific brain functions.
The leads are connected to a compact, battery-operated generator implanted near the collar bone in a fashion similar to a heart pacemaker. Electrical brain stimulation is intended to rebalance neural circuits and influence nerve activity. DBS offers the advantage of being programmable and reversible.
The patients involved in the trial received DBS implants in 2009-2010. Surgeons targeted the LHA, which prior studies have pinpointed as a promising neurostimulation target to supplement weight-loss efforts for morbidly obese patients who had failed other weight loss attempts.
An individual is considered morbidly obese if he or she is 100 pounds over his or her ideal body weight, has a body mass index (BMI) of 40 or more. BMI is the ratio of an individual’s height to his or her weight, with BMI between 20 and 25 considered to be the healthiest weight range.
“These patients have struggled for years to control their weight, without success,” said Dr. Oh. “We hoped to prove that we could safely alter metabolism with DBS and eventually provide another alternative for achieving a healthy weight for patients who could not do so through dieting and traditional weight loss surgery.”
With collaborators at Pennington Biomedical Research Center in Baton Rouge, LA, Dr. Oh and his colleague [Donald Whiting, MD, arranged for the patients to undergo detailed metabolic studies over the course of five days. The metabolic studies enabled the physicians to pinpoint the optimal DBS settings for each patient.
Based on results of individually testing stimulation with a different electrical contact on the DBS leads each day, the researchers chose a stimulation regime that showed the greatest effect in raising resting metabolic rate. The rate was measured while the patients rested comfortably in an enclosed metabolic chamber where their respiration and related factors were analyzed.
The team measured each patient’s resting metabolic rate by averaging the several readings of the amount of calories burned while the patient was inactive. This baseline rate, calculated when the stimulator was off, was then compared with various readings taken while the stimulator was activated to determine how DBS changed the metabolic rate.
After nine months, one patient experienced a 9 percent increase in resting metabolic rate and reduced his weight by 16.4 percent. Another patient lost 12.3 percent of her weight after 11 months at the optimal setting. The final patient had a 0.9 percent decrease in weight after 16 months at optimal settings.
“This patient also commented that this was the first time in her life that she did not have to fight constant hunger and her binge eating score reduced from severe to within normal range,” said Dr. Whiting, Director of the Center for Spasticity and Movement Disorders at Allegheny General. “We’re hopeful that expanded research studies might show that optimal settings would reduce appetite and food cravings in many patients.”
With the existing patients, the team continues to monitor effects of hypothalamic deep brain stimulation and examine persistence of the impact on metabolic rate.
“In order for survival during lean times, humans have evolved to automatically lower metabolic rate when food intake goes down – an innate ‘set point’ that can add challenge to weight-loss efforts,” Dr. Oh said. “Our research suggests that the ‘set point’ can be adjusted like a thermostat.”
About Allegheny General Hospital
The Neurosciences Institute at AGH integrates renowned experts in the subspecialties of neurology, neurotology, neuroradiology, neuro-critical care, and neurosurgery to offer world class care for patients with the most complex neurological disorders. Recognized as both a Neurosciences Center of Excellence and a Spine Center of Excellence, the program serves as a national and international referral center for treatment of all types of neurological conditions.
About the International Neuromodulation Society (INS)
The INS is a nonprofit group of clinicians, scientists and engineers dedicated to scientific development and knowledge of neuromodulation, a rapidly growing family of therapies developed to help relieve pain or restore function by delivering electromagnetic stimulation or chemical agents to specific sites in the body. Founded in 1989 and based in San Francisco, Calif., the INS has 15 current and four forming chapters worldwide, and educates and promotes the field through meetings, its journal Neuromodulation: Technology at the Neural Interface, and chapter websites.
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