Effect of rTMS in Combination With a Low-carbohydrate Diet in Patients With Obesity

Effect of Repetitive Transcranial Magnetic Stimulation in Combination With a Low-carbohydrate Diet in Patients With Obesity: a Randomized Controlled Study

In the present study the investigators want to evaluate if the application of rTMS can reduce the anxiety and craving in patients with obesity helping them to follow a low carb-diet, as well as, to assess the changes in weight, body mass index and quality of life before and after rTMS or sham rTMS.

Participants completed a written, informed consent and rTMS adult safety questionnaire. The inclusion criteria are: individuals between 25 and 60 years of age with obesity in stage 1, 2 or 3. The exclusion criteria were: subjects with metabolic disorders, neurological condition, epilepsy, or pregnancy. The study conformed to the Declaration of Helsinki and was approved by the Institutional Medical Research Ethics Committee (Hospital Ajusco Medio, Mexico DF). The protocol will be applied as follows: 10 rTMS or sham sessions during two weeks. Following these two week, patients will receive 8 more sessions on weeks 4, 6, 8, 10, 12, 16, 20 and 24. Diet will be indicated during all the protocol. The sham group will receive sham rTMS sessions for two weeks, the additional sessions will be performed in the same manner thar in rTMS group.

Study participants will be randomly assigned to one of two groups: the experimental group receiving rTMS and a placebo group receiving sham rTMS. Both groups will be on the low-carb diet.

Sham rTMS will be administered with the coil held in contact with the head but at 180 degrees from scalp to avoid stimulation.

A Magstim Rapid2 Stimulator equipped with a double 70mm alpha coil P/N 3191-00 (Magstim, Wales, UK) will be used to stimulate the motor cortex. Transcranial magnetic stimulation will be applied through a coil at 10 Hz, a field intensity of 90% of the motor threshold. Stimuli will be provided in 10 trains of 100 pulses, followed by a 28 s rest period.

Sham rTMS will be administered with the coil held in contact with the head but a 180 degrees from scalp, and the power parameter will be reduced by half to avoid stimulation.b

Patients will be stimulated in the dorso lateral frontal cortex. First, the motor threshold will be determined for each patient. To induce currents to the left primary sensory-motor cortex hand area (M1/S1) the coil will be placed over the scalp oriented at 45 ° from the mid-sagittal plane while subjects will sit comfortably on a chair. The coil will be systematically moved in this area until a contraction of the abductor will be identified. Motor evoked potentials (MEPs). MEPs will be registered with surface electrodes on the left hand abductor pollicis muscle using the same Magstim equipment. Then the parameters will be adjusted for the stimulation as was described before.

As well as the rTMS group, the motor threshold of each patient will be determined. They will experience a similar rTMS session with the difference that they not will be stimulated.

This intervention will be applied to both groups, rTMS and sham group, as a combined therapy. The diet is low in carbohydrates, like sugary foods, pasta and bread. Instead, patients eat food with protein, natural fats and vegetables.

Inclusion Criteria: BMI > 30 Exclusion Criteria: Thyroid problems, anorexia, bulimia, epilepsy, schizophrenia

Alonso-Alonso M, Pascual-Leone A. The right brain hypothesis for obesity. JAMA. 2007 Apr 25;297(16):1819-22. doi: 10.1001/jama.297.16.1819. No abstract available.

Kober H, Mende-Siedlecki P, Kross EF, Weber J, Mischel W, Hart CL, Ochsner KN. Prefrontal-striatal pathway underlies cognitive regulation of craving. Proc Natl Acad Sci U S A. 2010 Aug 17;107(33):14811-6. doi: 10.1073/pnas.1007779107. Epub 2010 Aug 2.

Barth KS, Rydin-Gray S, Kose S, Borckardt JJ, O'Neil PM, Shaw D, Madan A, Budak A, George MS. Food cravings and the effects of left prefrontal repetitive transcranial magnetic stimulation using an improved sham condition. Front Psychiatry. 2011 Mar 14;2:9. doi: 10.3389/fpsyt.2011.00009. eCollection 2011.

Uher R, Yoganathan D, Mogg A, Eranti SV, Treasure J, Campbell IC, McLoughlin DM, Schmidt U. Effect of left prefrontal repetitive transcranial magnetic stimulation on food craving. Biol Psychiatry. 2005 Nov 15;58(10):840-2. doi: 10.1016/j.biopsych.2005.05.043. Epub 2005 Aug 8.