Identification of Vocal Cord Dysfunction Phenotypes by Latent Class Analysis

Vocal Cord Dysfunction (VCD) is the inappropriate adduction of the vocal cords during respiration. Clinical presentation of VCD is heterogenous and is often induced by a range of stimuli including irritant exposure and emotional stress. The existence of several VCD phenotypes has been postulated. We used Latent Class Analysis (LCA) to identify VCD phenotypes. <bold>Methods:</bold> Consecutive patients with confirmed VCD were assessed between March 2016 and September 2023. LCA analysed by age, professional voice use, self-reported triggers (inhaled trigger, exertion, stress, eating/talking, presumed allergen exposure) and comorbidities (hyperventilation, anxiety, sino-nasal disease, lower airway obstruction, gastroesophageal reflux, obesity). Identified classes were compared by clinical course, laryngoscopy findings, and patient-reported outcomes. <bold>Results:</bold> 192 patients evaluated by LCA identified 4 classes as the optimal outcome by statistical criteria; isolated VCD (33%,n=63); hyperventilation-associated VCD (40%,n=80); polymorbid-associated VCD (20%,n=35); and patient-presumed allergen-triggered VCD (7%,n=14). Polymorbid-associated VCD was associated with higher VCD Questionnaire, lower Laryngeal Hypersensitivity Questionnaire scores, and expiratory phase-limited VCD (all p<0.01). Patient-presumed allergen-associated VCD had higher (less impairment) chemical sensory hyperreactivity (p<0.01), shorter duration of symptoms (p=0.05) and were the least likely to respond to laryngeal retraining (p=0.02). <bold>Conclusion:</bold> Four clinically distinct VCD phenotypes characterized by differences in clinical features, laryngoscopy findings and patient-reported outcomes support the concept of distinct pathogenic mechanisms in VCD.