Associate Professor UCSF Voice and Swallowing Center University of California, San Francisco San Francisco, California
Background/Objectives: Laryngeal sensory abnormality has been proposed as an etiology of spasmodic dysphonia. We objectively assessed laryngopharyngeal sensation in Adductor Spasmodic Dysphonia (AdSD) patients utilizing a calibrated, tactile aesthesiometer to deliver differential tactile stimuli to lateral pyriform sinus (PS), aryepiglottic (AE) fold, and false vocal fold (FVF).
Methods: Patients with Botox-responsive AdSD underwent sensory testing using a previously-validated methodology involving calibrated tactile stimuli (6-0, 5-0,4.5-0, 4-0 nylon monofilaments). Laryngeal adductor reflex (LAR) was recorded, and participants rated perceptual strength of each stimulus. Responses were compared to normative controls (n=32). Mixed-effects statistical model assessed association of filament size, stimulus site, and AdSD status on LAR and perceptual strength rating. Two-sample Mann-Whitney and Fisher exact tests compared mean strength ratings and LAR between AdSD and control groups.
Results: Ten AdSD patients (7 women, mean age 50+/-17 years) completed testing. Increased LAR rates were significantly correlated with more medial laryngopharyngeal site (p <.001), but not with increased filament size (p=0.272). LAR response rate was increased in AdSD vs controls with 6-0 at PS (50% vs 8%, p=0.002) and AE (100% vs 39%, p=0.002) but not with FVF or other-sized filaments. Mean perceptual strength was statistically different for 6-0 and 5-0 at AE (p=0.0015 and 0.045, respectively).
Conclusions: This is the first study to objectively assess laryngopharyngeal sensation in AdSD. In this study, findings demonstrate increased laryngopharyngeal sensation in AdSD patients compared to controls. The identification of increased laryngeal hypersensitivity in these patients may improve understanding of AdSD pathogenesis and identify future targets for intervention.