Clinical trial NCT02065128: The Efficacy of Capsaicin Sensitivity Testing in Patients With Irritable Larynx Syndrome
Official title: The Efficacy of Capsaicin Sensitivity Testing in Patients With Irritable Larynx Syndrome
Study type: OBSERVATIONAL
Overall status: WITHDRAWN
Conditions: Cough
Larynx
Lead sponsor: Unity Health Toronto
Sponsor class: OTHER
First posted: 2014-02-17
Enrollment: 0
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_CONTROL
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: ILS Patients

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.

Eligibility 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:

Exclusion Criteria:

* Active smoker
* Active respiratory disease (e.g. COPD, asthma)
* ILS diagnosis
* Chronic cough diagnosis
* Known hypersensitivity to capsaicin

Primary outcomes:
measure: cough reflex sensitivity
timeFrame: measured before and after behavioural therapy for ILS participants (approximately 5 month time frame); measured once for healthy volunteers
Secondary outcomes:
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: St. Michael's Hospital
state: Ontario
Study officials:
affiliation: Chief, Department of Otolaryngology - Head and Neck Surgery
name: Jennifer Anderson, MD, FRCS(C)
role: PRINCIPAL_INVESTIGATOR
References: