Investigating the Effects of Intensity of Transcranial Direct Current Stimulation on Subjective Appetite

Study Overview
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Brief Summary
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This is a randomized double-blind sham controlled systematic investigation to understand the importance of the brain region that controls the tongue and the submental muscle region on perceived appetite. The results of this study can have clinical implications for a phenomenon called hyperphagia.

Detailed Description
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After explaning all the procedure and the scientific aims of the project to participants and completing the informed consent form, each participant will be randomly asked to take part in the experiment while fasting for at least 6 hours or completely sated, to enable an investigation of the role of the basic level of hunger on the effects of brain stimulation on subjective appetite. Different intensities of stimulation (1 mA, 1.5 mA, and sham) will be used in three separate groups, to which participants will be randomly assigned, in a double-blind manner.

Official Title
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Investigating the Effect of the Intensity of Primary Motor Cortex Cathodal tDCS on Appetite; A Double-blind Sham-controlled Study

Conditions
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Healthy

Intervention / Treatment
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* Device: 1 mA tDCS
* Device: 1.5 mA tDCS
* Device: Sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Normal weight, based on the Body Mass Index (BMI) Males and females between 18 and 35 Exclusion Criteria: Use of psychoactive drugs Presence of metal implants in the brain, skull, scalp or neck Use of pacemaker Neurological or psychiatric pathologies History of severe head injury Pregnancy Clinical obesity based on BMI

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants will be randomly allocated to one of the three groups of active 1 mA, active 1.5 mA, or the sham group.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1 mA tDCS<br>Participants receive the stimulation with an intensity of 1 mA. | Device: 1 mA tDCS<br>* One session with stimulation intensity of 1 mA.<br>|
| Experimental: 1.5 mA tDCS<br>Participants receive the stimulation with an intensity of 1.5 mA. | Device: 1.5 mA tDCS<br>* One session with stimulation intensity of 1.5 mA.<br>|
| Sham Comparator: Sham tDCS<br>Participants receive the sham stimulation (zero electric current after a short initial increase). | Device: Sham tDCS<br>* One session of sham stimulation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in the subjective rating of appetite | A visual analogue scale (VAS; from 0 meaning not hungry at all, to 100 meaning extremely hungry), will be used to record the perceived level of hunger before and after the stimulation to enable evaluation of the effects of stimulation on perceived appetite. | Baseline measurement in the begninning of the experiment before stimulation versus post stimulation, exactly after the stimulation protocol has finished (with an approximate time interval of 1 hour) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in excitability of the submental muscle region in primary motor cortex | Recording motor evoked potentials from the area of the submental region of the motor cortex in addition to a control site (APB muscle), to allow for comparisons of the amplitude of MEPs before and after stimulation to draw conclusions about the effect of stimulation and its contribution to the potential behavioral modulations of tDCS | Baseline measurement in the begninning of the experiment before stimulation versus post stimulation, exactly after the stimulation protocol has finished (with an approximate time interval of 1 hour) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Perceived appetite, tDCS, Submental muscle, M1