Vocal Cord Responses During Hyperventilation in Normal Individuals and in Mild and Severe

16151A

The Investigators aim to: 1. Study the effect of hyperventilation on the development of paradoxical vocal cord movement (PVCM) in healthy individuals and in patients with mild and severe asthma, 2. Relate PVCM to airway symptoms and measurements of intra- and extra-thoracic airway hyperresponsiveness (ET-AHR), 3. Evaluate the effects of inhaled anti-cholinergic agents on PVCM induced by hyperventilation. Hypotheses: 1. In health PVCM will not occur in response to hyperventilation, 2. In asthma PVCM will occur in response to hyperventilation, 3. Airway symptoms and ET-AHR will develop in parallel with PVCM, 4. Inhaled anticholinergic agents will prevent PVCM induced by hyperventilation.

2018-06-01

2024-12-01

2024-12-01

Recruiting

24

Inclusion Criteria for Healthy Controls: * Inclusion criteria for healthy controls include: * age \>18 to 65 years old * non-smokers * No history of chronic respiratory symptoms. Exclusion Criteria for Healthy Controls: * Exclusion criteria for controls include: * Age \< 18 or \> 65, smokers or smoking history \>10 pack years * Any history of respiratory disorders such as asthma or chronic obstructive pulmonary disease (COPD) * Known vocal cord pathology (i.e. laryngeal cancer) or diagnosed voice condition * Known brain or brainstem cancer * Known head and neck cancer * Known neurological disorders (i.e. stroke) * Use of medications (i.e. beta-blockers or anti-cholinergic agents which may interfere with vocal cord function) * Singers * Pregnancy. Inclusion Criterial for Asthmatics: * The Investigators shall recruit a total of 16 patients with asthma - 8 patients with mild asthma (Group 2) and 8 patients with severe asthma (Group 3). * Mild asthma will be defined as patients with forced expiratory volume in 1 second (FEV1) \>80% predicted. * Severe asthma will be defined as patients with FEV1 50-60% predicted. * Asthmatics will also have a forced expiratory ratio (FER) less than the lower limit of normal, indicating obstruction. * Inclusion criteria will include: * age 18-65 years * A history of asthma defined as a bronchodilator response with increase in FEV1 \>12% and 200mls or positive bronchoprovocation testing (methacholine). * Asthmatics will have FEV1 \>50% predicted. Exclusion Criteria for Asthmatics: - Exclusion criteria will include: * Age \< 18 or \> 65 * Smoking history \> 10 pack years, * FEV1 \< 50% predicted * Allergy to anti-cholinergics, known COPD * Known vocal cord pathology (i.e. laryngeal cancer) or diagnosed voice condition * Known brain or brainstem cancer * Known head and neck cancer * Known neurological disorders (i.e. stroke) * Singers * Pregnancy

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2023-10-23