Effect of Non-invasive Magnetic Stimulation of the Brain on Breathlessness in Healthy Individuals.

Oxford Brookes University21 enrolled

Overview

The purpose of this study is to see if the front part of the brain called the "Dorsolateral Prefrontal Cortex" (DLPFC) has a role in our ability to feel breathlessness. The experiment will use a device that sits on the top of the head which produces a magnetic field that penetrates the scalp and excites the brain tissue directly under it. This procedure is called repetitive transcranial magnetic stimulation (rTMS), it is a painless procedure and known to be safe in healthy individuals. Previous research has shown that the pain felt when capsaicin, the active ingredient in 'chilli' powder, is applied to the hand is reduced by applying the rTMS on the scalp directly above the DLPFC part of the brain. In this experiment we want to see if breathlessness is also reduced. We will use a breathing task that will generate a moderate amount of breathlessness by adding a small amount of carbon dioxide to the inhaled air, while preventing the increase in the amount of breathing we would normally see in response to this. If we find that breathlessness produced by this breathing task is reduced after rTMS over the DLPFC, this may lead to new drugs that target this part of the brain in patients suffering from breathlessness due to heart or lung disease. The study will also improve our knowledge of how the brain enables us to feel breathlessness

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

Conditions

Dyspnea

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: healthy individuals, over 18 years old, with no history of heart, lung or neurological conditions Exclusion Criteria: * Any history of respiratory problems (including Asthma that involves regular use of inhalers) * Any history of heart or circulatory problems (e.g. palpitations, arrhythmias, angina, BP) * Any history of epilepsy, convulsions or seizures, migraines, or fainting * Any history of anxiety disorders (e.g. panic attacks) * Any history of serious head injury or brain surgery * Any metal parts in the head (except dental wire) * Any implants (e.g. pacemaker, insulin pump, neurostimulator) * Pregnancy or problems with alcohol or drug abuse.

Outcomes

Primary Outcomes

Air hunger

Ratings of air hunger on a 100mm Visual analog scale with the extremes defined as 'non' and 'tolerable limit'

Time frame: Average of 4 steady state ratings in the last minute of air hunger tests

Secondary Outcomes

Bond Lader Mood questionnaire scores

Ratings provided on a 100mm visual analogue scale anchored by a negative mood descriptor at one extreme and the opposing positive mood descriptor at the other extreme. The average scores for 'sedation' descriptors, 'discontentment' descriptors, and 'relaxation' descriptors are each expressed as %maximum

Time frame: Questionnaire administered immediately following pre and post intervention air hunger tests for how participants were feeling at that moment in time.

Spielberger's state-trait anxiety inventory (STAI form Y-1 and form Y2) scores

20 is the lowest score and 80 is the highest score for both state (form Y-1) and trait (Form Y-2) anxiety

Time frame: Form Y-2 (trait anxiety) administered once on the initial practice day. Form Y-1 (state anxiety) administered immediately following pre and post intervention air hunger tests on test days.

Dyspnoea-12 total, physical and emotion scores

For Total score; zero indicates no dyspnoea and 36 indicates worst possible dyspnoea (expressed as %fullscale). For Physical score; zero indicates no dyspnoea in the physical domain and 21 indicates worst possible dyspnoea in physical domain (expressed as %fullscale). For Emotion score; zero indicates no dyspnoea in emotion domian and 15 indicates worst possible dyspnoea in emotion domain (expressed as %fullscale).

Time frame: Administered immediately following pre and post intervention air hunger tests in relation to the "test just completed"