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.
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).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Masking
SINGLE
Enrollment
30
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)
Hopital Raymond Poincare
Garches, Garches, France
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)
Time frame: About 90 min (duration of the study visit)
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)
Time frame: 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)
Time frame: About 90 min (duration of the study visit)
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