Effect of Non Invasive Brain Stimulation on Experimentally Induced Dyspnea (Breathlessness)

Study Overview
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Brief Summary
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Dyspnea is a frequent, mostly unpleasant and long-lasting, but also often undertreated symptom. Transcranial direct current stimulation (tDCS), a new non invasive method to modify brain activation has shown good efficacy in the treatment of pain especially in the clinical context. Given the fact that dyspnea has many common characteristics with pain, especially concerning the brain areas involved in its central processing, we hypothesize that tDCS may also modify the perception of dyspnea. In order to test this, we first shall determine whether tDCS has a significant effect on acutely induced dyspnea in healthy volunteers. In case of promising results of this pilot study, the next step will be the evaluation of the benefit of tDCS in patients with severe dyspnea.

Detailed Description
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Dyspnea will be induced by breathing through a combination of an external resistive load and a long tube (inducing CO2 rebreathing) (resulting in a sensation of both increased respiratory effort and air hunger). tDCS will be applied during 15 minutes either over the motor/premotor or over the insular cortex (i.e. 2 brain regions that have previously been shown to be involved in dyspnea perception and/or modulation) in 2 parallel groups of healthy subjects. For each study group, the effect of tDCS on dyspnea perception and on respiratory parameters will be compared between 2 active (anodal and cathodal) and a sham tDCS stimulation (placebo).

Official Title
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Effect of Transcranial Direct Current Stimulation (tDCS) on Acutely Induced Dyspnea in Healthy Volunteers : a Pilot Study

Conditions
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Dyspnea

Intervention / Treatment
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* Device: tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Registered at the National List of persons taking part in clinical research Signed consent form Subjects of both genders aged of at least 18 years Perfect understanding of the instructions and of sensory scaling Prior medical examination Exclusion Criteria: Any current or past disease, in particular respiratory, neurological and psychiatric disorders Regular use of drugs, especially those having an impact on respiratory, neurological systems (most specifically those with an effect on the central nervous system) Unwilling to participate Vulnerable people as defined in the provisions relating to biomedical researches and described in the Code of Public Health. Unable to cooperate Pregnancy or lactation No affiliation to a social security system.

Ages Eligible for Study
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Minimum Age: 18 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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: motor/premotor cortex stimulation<br>Active and sham tDCS applied over the motor/premotor cortex | Device: tDCS<br>* Procedure : 3 different sessions of tDCS (listed below) presented in random order, each applied at a different study visit Anodal tDCS: Intensity of 1.25 milliAmperes (mA) during 15 min Cathodal tDCS: Intensity of 1.25 mA during 15 min Sham tDCS (placebo) (1.25 mA maintained only during the first 30 sec of the 15 minutes application)<br>* Other names: Eldith DC stimulator (Magstim Company Ltd. UK);|
| Experimental: insular cortex stimulation<br>Active and sham tDCS applied over the insular cortex | Device: tDCS<br>* Procedure : 3 different sessions of tDCS (listed below) presented in random order, each applied at a different study visit Anodal tDCS: Intensity of 1.25 milliAmperes (mA) during 15 min Cathodal tDCS: Intensity of 1.25 mA during 15 min Sham tDCS (placebo) (1.25 mA maintained only during the first 30 sec of the 15 minutes application)<br>* Other names: Eldith DC stimulator (Magstim Company Ltd. UK);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of active versus sham tDCS on perceived intensity (sensory component) of induced dyspnea | Change from baseline (before tDCS application) in intensity of experimentally induced dyspnea (in Borg scale scores) at 4 different time points, 1 during and 3 after each of the 3 tDCS applications (anodal, cathodal and sham) | About 90 min (duration of the study visit) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of active versus sham tDCS on perceived unpleasantness (affective component) of induced dyspnea | Change from baseline (before tDCS application) in unpleasantness of experimentally induced dyspnea (in Borg scale scores) at 4 different time points, 1 during and 3 after each of the 3 tDCS applications (anodal, cathodal and sham) | About 90 min (duration of the study visit) | 
| Effect of active versus sham tDCS on respiratory variables during induced dyspnea | Change from baseline (before tDCS application) in mouth pressure swings (cm H2O), tidal volume (L), respiratory frequency (cycles/min), minute ventilation (L/min) and end tidal carbon dioxide (PetCO2)(mm Hg) at 4 different time points, 1 during and 3 after each of the 3 tDCS applications (anodal, cathodal and sham) | About 90 min (duration of the study visit) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dyspnea, Transcranial direct current stimulation (tDCS), Perception