Efficacy of SLN Block for Chronic Cough

Efficacy of Superior Laryngeal Nerve Block for Chronic Cough

This is a research study to find out if superior laryngeal nerve blocks are an effective way to reduce cough when compared to placebo (a substance without any medical value). Eligibility for the study include the following: age >18, cough history suggestive that the nerve to the voice box is overactive, non-smoker, Patients will be followed over time and assigned to either the treatment or placebo group at random. The treatment would be four superior laryngeal nerve blocks and the placebo would be four saline injections (the inactive substance). Study team will measure if the injection improved cough and ask patients to keep a log of symptoms and fill out questionnaires at each visit. After the four injections, patients will follow up in 3 months to see if cough has returned and if so, how severe the cough is.

Study Overview

• Status: Completed
• Conditions: Cough; Superior Laryngeal Nerve Block; Neurogenic Cough
• Intervention / Treatment: Procedure: Superior laryngeal nerve block; Procedure: Injection of steroid-lidocaine mixture; Procedure: Injection of placebo (saline)

• Study Type: Interventional
• Enrollment (Actual): 17
• Phase: Phase 3

Contacts and Locations

Study Locations

• United States
  • South Carolina
    • Charleston, South Carolina, United States, 29403
      • Medical University of South Carolina

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• History consistent with neurogenic cough
• Exclusion of other etiologies (see exclusion criteria)
• Age ≥ 18

Exclusion Criteria:

• Current neuromodulating medication use
• Untreated other etiologies of cough:

Current smoker Current ACE/ARB use Abnormal PFTs within 6 months Uncontrolled OSA Abnormal CXR within 6 months RSI > 13 or RFS >11 AND workup positive for GERD (esophagram, 24-hour pH probe, manometry, EGD)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Steroid-Lidocaine Mixture; Will receive numbing injection, which is a mixture of steroid and lidocaine	Procedure: Superior laryngeal nerve block; Injection of either the steroid-lidocaine mixture or placebo through the skin around where the superior laryngeal nerve is located on the neck. The procedure lasts 5 minutes and is done in the clinic.; Other Names: Injection of steroid-lidocaine mixture vs. placebo (saline); Procedure: Injection of steroid-lidocaine mixture; Superior laryngeal nerve block using 1mg 1:1 triamcinolone 40mg: 1% lidocaine with 1:200000 epinephrine as the injection.; Other Names: 1mg 1:1 triamcinolone 40mg: 1% lidocaine with 1:200000 epinephrine as the injection.
Placebo Comparator: Placebo; Will receive saline injection as a placebo	Procedure: Superior laryngeal nerve block; Injection of either the steroid-lidocaine mixture or placebo through the skin around where the superior laryngeal nerve is located on the neck. The procedure lasts 5 minutes and is done in the clinic.; Other Names: Injection of steroid-lidocaine mixture vs. placebo (saline); Procedure: Injection of placebo (saline); Superior laryngeal nerve block using 1mL of saline as the injection.; Other Names: 1mL of saline as the injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Cough Severity	Patient will complete the Leicester Cough Questionnaire at each visit. This is a validated survey that measures 3 domains (physical, psychological and social). The total score range is 3-21 and domain scores range from 1-7; a higher score indicates a better quality of life.	Change from Baseline to 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Subjective Improvement in Cough	Improvement was defined as a 'yes' response at any time point during the study (1-4 weeks or 3 months post-treatment). The reported value reflects the total number of participants who reported improvement at any time point.	Baseline, 1-4 weeks post-injection, and 3 months post-treatment
Summed Daily Change in Subjective Cough Severity	Participants rate cough severity on a 0-15 visual analogue scale. Scores are recorded daily and analyzed using regression. Higher scores indicate greater severity. VAS is a 0-15 scale completed daily by participants. Severity is measured using a ruler to determine percentage along the scale. Scores were analyzed using regression models to assess trends over time.	Daily for 3 months post-injection

Collaborators and Investigators

• Sponsor: Medical University of South Carolina
• Investigators: Principal Investigator: Courtney Tipton, Medical University of South Carolina

Study record dates

Study Major Dates

• Study Start (Actual): July 22, 2020
• Primary Completion (Actual): December 30, 2022
• Study Completion (Actual): December 30, 2022

Study Registration Dates

• First Submitted: June 4, 2020
• First Submitted That Met QC Criteria: June 4, 2020
• First Posted (Actual): June 9, 2020

Study Record Updates

• Last Update Posted (Estimated): October 23, 2025
• Last Update Submitted That Met QC Criteria: September 25, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: chronic cough; superior laryngeal nerve block
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Signs and Symptoms, Respiratory; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Chronic Cough; Cough; Organic Chemicals; Hydrocarbons; Hydrocarbons, Cyclic; Hydrocarbons, Aromatic; Polycyclic Compounds; Anilides; Amides; Aniline Compounds; Amines; Acetanilides; Inorganic Chemicals; Chlorine Compounds; Pregnadienes; Pregnanes; Steroids; Fused-Ring Compounds; Steroids, Fluorinated; Catechols; Phenols; Benzene Derivatives; Alcohols; Amino Alcohols; Ethanolamines; Biogenic Monoamines; Biogenic Amines; Catecholamines; Sodium Compounds; Chlorides; Hydrochloric Acid; Lidocaine; Triamcinolone; Epinephrine; Sodium Chloride
• Other Study ID Numbers: 00096384

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No