ABSTRACT Addington WR, Stephens RE, Widdicombe JG, Anderson JW, Rekab K: Effect of tartaric acid-induced cough on pulmonary function in normal and asthmatic humans. Am J Phys Med Rehabil 2003;82:374-378. Objective: The laryngeal cough reflex and the laryngeal cough expiratory reflex are brainstem reflexes that protect the upper airway from significant aspiration. The purpose of this investigation was to examine the effects of tartaric acid-induced cough on pulmonary function in normal healthy and asthmatic individuals. Design: Twenty healthy and 20 asymptomatic, medicated, asthmatic volunteers engaged in a two-part evaluation of pulmonary function testing. All 40 subjects were nonsmokers. The reflex cough test, a 20% solution of prescription-grade L-tartaric acid dissolved in 0.15 M NaCl solution, initiated the laryngeal cough expiratory reflex/laryngeal cough reflex. The solution was placed in a Bennett Twin nebulizer and inhaled as a microaerosol. Pulmonary function testing was with a Spiromate AS-600. Baseline pulmonary function testing was initially performed, followed by two separate inhalations of the reflex cough test. The pulmonary function testing was repeated 5 min after the second reflex cough test. Results: Statistically significant changes seen after the reflex cough test included increases in the peak inspiratory flow in normal subjects (P = 0.004) and in the peak expiratory flow in asthmatic subjects (P = 0.014). No respiratory adverse events occurred after the reflex cough test. Conclusions: Explanations for these findings include the possibility that tartaric acid-induced cough produces central nervous system-mediated bronchodilatation, through the cough itself or by secondary mechanisms. Key Words: Reflex; Laryngeal; Tartrates; Asthma; Pulmonary; Cough >From Brevard Rehabilitation Medicine, Melbourne, Florida (WRA); the Department of Anatomy, University of Health Sciences, Kansas City, Missouri (RES); Human Physiology and Aerospace Medicine, GKT School of Biomedical Sciences, Shepherd's House, Guy's Campus, London, UK (JGW); the Ability Rehab Associates, Salisbury, Maryland (JWA); and the Florida Institute of Technology, Melbourne, Florida (KR). Presented at the Second International Symposium on Cough Pharmacology and Therapy at the National Heart and Lung Institute, Royal College of Medicine, London, UK, October 25-26, 2001. The reflex cough test (Pneumoflex) of the laryngeal cough reflex is patented and trademarked by Pneumoflex Systems (Melbourne, FL) and is entering FDA phase 3 clinical trials. None of the authors has been financially compensated for the research associated with this article. Unrelated to this article, a commercial party with a direct financial interest in the reflex cough test may confer a financial benefit on one or more of the authors. All correspondence and requests for reprints should be addressed to W. Robert Addington, DO, 200 Ocean Avenue, Suite 201, Melbourne Beach, FL 32951. American Journal of Physical Medicine & Rehabilitation 2003; 82(5):374-378 Copyright © 2003 Lippincott Williams & Wilkins All rights reserved