Laryngeal Sensory Testing and Superior Laryngeal Nerve Block for Neurogenic Cough

Introduction: Neurogenic cough is a chronic cough subtype often associated with abnormal sensory function of the internal branch of the superior laryngeal nerve (SLN). A safe and effective treatment involves percutaneous injection of anesthetic and corticosteroid at the site of the SLN. We assessed whether abnormal laryngeal sensory testing was predictive of success of an ipsilateral SLN block.

Methods: Retrospective chart review was performed on adult patients with chronic cough who underwent laryngeal sensory testing and staged SLN blocks by a single laryngologist between 2018 and 2023. The relationship between outcome of laryngeal sensory testing and benefit with SLN block was evaluated.

Results: In total, 22 patients were included; mean age at presentation was 70 years and 68.2% were female. Of those, 15 patients exhibited laryngeal hypersensitivity on examination. Of those patients, 11 (73.3%) also demonstrated a response to SLN block compared to 4 (57.1%) without hypersensitivity (p = 0.63, Fisher’s exact test). Of the 15 patients, 9 (60%) demonstrated a concordance between side of hypersensitivity and side of benefit with SLN block. A binomial test (n = 15) assuming expected probability of perfect match of 50% was performed (p = 0.26). Two patients (13.3%) had improvement from a contralateral SLN block, while 4 (26.6%) had no benefit with either SLN blocks.

Conclusions: Although results were not statistically significant for concordance between side of laryngeal hypersensitivity and side of improvement with SLN block, a trend towards ipsilateral concordance was observed. This study corroborates prior studies demonstrating a lack of predictive accuracy when using patient characteristics to identify successful SLN block candidates. Future studies with a larger patient cohort are needed to confirm whether laryngeal sensory testing can predict SLN block success for treatment of neurogenic cough.