Laryngeal Cryotherapy for Refractory Neurogenic Cough

Study Overview
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Brief Summary
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This study aims to evaluate the safety and efficacy of upper aerodigestive tract cryotherapy treatment in patients with refractory neurogenic cough in a prospective pilot study with a validated patient reported outcome measure

Detailed Description
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This study aims to test a new type of treatment for patients suffering from chronic cough, also known as upper airway cough syndrome. The new treatment involves the use of laryngeal cryotherapy which is the therapeutic freezing of tissue in the throat to numb the overactive sensory nerves in the throat which is believed to reduce cough symptoms. Patients will first undergo a flexible scope of the throat (laryngoscopy) to test for hypersensitive areas in the throat, then undergo the cryotherapy procedure in the office. After that, patients will be followed up in the clinic with the usual standard of care visits and undergo validated cough surveys to track their cough symptoms after the procedure. Possible side effects to this procedure are listed in detail below, and include temporary throat pain and coughing.

Official Title
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To Determine the Efficacy of Topical Cryotherapy on Supraglottic Laryngeal Mucosa in the Treatment of Chronic Neurogenic Cough in Adult Patients

Conditions
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Upper-Airway Cough Syndrome

Intervention / Treatment
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* Procedure: Laryngeal cryotherapy
* Device: Cryoprobe


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients 18 years or older with diagnosis of neurogenic cough Neurogenic cough is a diagnosis of exclusion applied to persistent cough (8 weeks or longer) Negative workup for other causes, including sinonasal allergies/chronic sinusitis, cough-variant asthma, and GERD Patient willing to participate in a clinical trial Exclusion Criteria: Uncontrolled reflux (scoring on Reflux Symptom index of 13 or higher) Vocal fold abnormalities or impairment History of asthma or other underlying lung condition not adequately treated or controlled Uncontrolled Allergic Rhinitis (Total Nasal Symptom Score >6, which would indicate moderate disease32) Reported symptom of postnasal drip Current smoker Current neuromodulator medication use Patient unwilling to participate in clinical trial or sign an informed consent End stage medical disease with poor life expectancy Medical instability deemed by the investigators as a contraindication for enrollment Abnormal Chest X-ray Abnormal pulmonary function testing (PFTs) Positive local allergy panel (combined RAST testing)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Upper airway cough syndrome<br> | Procedure: Laryngeal cryotherapy<br>* Laryngeal cryotherapy is the therapeutic freezing of tissue in the throat to numb the overactive sensory nerves in the throat. This technique is believed to reduce cough symptoms in this study.<br>Device: Cryoprobe<br>* Cryoprobe is FDA approved for use for the destruction of unwanted tissue along the respiratory tract<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Improved quality of life of patients suffering from chronic cough | This is a validated patient reported outcome measure for chronic cough. This is a questionnaire of 10 questions about cough symptoms, each question is rated on a scale of 0-4 by the patient. The higher the CSI total score the worsen the cough symptoms are for the patient. The CSI will be compared across 5 time points (Pre-Laryngeal Cryotherapy, 1 week post cryotherapy, 1 month post cryotherapy, 3 months post cryotherapy and 6 months post cryotherapy) using repeated measures one-way ANOVA. Post-hoc pair-wise comparisons with Bonferroni correction will be used, as appropriate. | 2 years | 
| Pre and Post-time point differences. | Sample size of 25 was determined based on expectations of a detectable significant within-group using a repeated measures ANOVA across 5 time points (add in the time points) with an alpha level of 0.0125, 85% power, and 1.246 effect size (based on previous work by Simpson et al PMID: 29668037.) needed to observe pre-post time point differences. | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pre- and post-treatment measures for the cryotherapy treatment group | This measure is the pre cryotherapy and 1 week post cryotherapy laryngeal aesthesiometer testing. This is a type of validated sensory testing of the larynx performed during an office flexible laryngoscopy where calibrated monofilaments are used to assess how sensitive certain parts of the larynx are. The data collected will be if a specific monofilament (size 6-0, 5-0, and 4-0) can trigger or not trigger a cough reflex when applied to specific subsites of the larynx (aryepiglottic fold, laryngeal aspect of epiglottis, false vocal fold, arytenoid prominence, and lateral and medial piriform sinus | 2 years |