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

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). *…