Cough, Larynx
Conditions
Brief summary
Irritable larynx syndrome (ILS) is a hyperkinetic laryngeal dysfunction that is characterized by a persistent cough, voice changes, or breathing difficulties, which are often triggered by an irritant. Diagnosis of ILS is difficult and typically made via a thorough review of the clinical history and, occasionally, the patient's reaction to an odor-provocation test. Standard treatment for ILS is behavioural therapy with a speech language pathologist (SLP), which provides symptom improvement for most patients. However, currently, there are no objective measures of the upper airway hyper-responsiveness in this condition to assist in diagnosing and monitoring disease severity. Since the cough is irritant-based, it is anticipated that patients with ILS will have a hypersensitivity to the irritant capsaicin. Capsaicin is the active component of chili peppers and is what makes them hot. The capsaicin cough challenge is a well recognized test that involves inhaling different concentrations of capsaicin solutions to determine a cough reflex sensitivity. The purpose of this research study is to confirm that ILS patients have a hypersensitivity to capsaicin compared to healthy volunteers. If a hypersensitivity is observed in ILS patients, the second objective of this study will be to see if behavioural therapy improves the cough reflex sensitivity in this patient population.
Detailed description
The proposed study has two purposes; the first is to utilize capsaicin cough challenge to demonstrate an increased efferent receptor sensitivity level in ILS subjects as compared to a control group. The second is to determine if there is an objective change in capsaicin cough challenge results after behavioral therapy, and whether it correlates to the subjective improvement. Self-reporting measures include two validated cough quality of life (QoL) questionnaires collected at the same intervals as the capsaicin testing.
Interventions
OTHERCapsaicin cough challenge test
The capsaicin cough challenge testing will be conducted in the pulmonary function laboratory at SMH by a pulmonary function technologist. The test involves having the participant inhale increasing concentrations of capsaicin solutions and assessing their response. The tidal breathing method and solution preparation presented by Nejla, et al. 12 will be used to conduct this testing. The tidal breathing method is preferred to the alternative dosimeter method as it produces similar results with lower capsaicin concentrations thereby resulting in less throat irritation for the participant. The technique is detailed in the following sections.
Sponsors
Unity Health Toronto
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
ILS Participants: Inclusion Criteria: * Diagnosis of ILS as per the St Michael's voice clinic consultation * Methacholine test performed * Negative/borderline result for methacholine test and/or negative/incomplete response for asthma treatment * Negative test result for gastroesophageal reflux or negative/incomplete response to reflux treatment * Allergy test has been completed with negative result or does not account for all symptoms * Agreed to behavioural therapy in SMH Voice Disorders Clinic
Exclusion criteria
* Active smoker * Active respiratory disease (e.g., COPD, pulmonary fibrosis, lung malignancy.) * Taking an ACE inhibitor * Pregnant and/or breastfeeding * Impaired liver and/or renal function * Neurological disorder * Psychiatric condition (outside of depression or anxiety) Healthy Volunteers:
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| cough reflex sensitivity | measured before and after behavioural therapy for ILS participants (approximately 5 month time frame); measured once for healthy volunteers | measured via the capsaicin cough challenge test |
Countries
Canada
Outcome results
None listed