Pilot Study of Respiratory–Swallow Coordination in Amyotrophic Lateral Sclerosis

Abstract

Purpose: Amyotrophic lateral sclerosis (ALS) impacts bulbar and respiratory musculature, which may contribute to impaired swallow function (dysphagia) and respiratory–swallow coordination. The purpose of this pilot study was to examine if respiratory–swallow coordination in individuals with ALS was perturbed compared to healthy controls. We further explored relationships between measures of respiratory function and self-reported swallowing outcomes on respiratory–swallow coordination. Method: We employed a cross-sectional design with eight participants with ALS and eight age- and sex-matched healthy participants. Respiratory inductance plethysmography and a nasal cannula were used to capture respiratory–swallow phase patterns during a standardized clinical swallow examination. The advantageous respiratory–swallow phase pattern was defined if exhalation surrounded the swallow (E–E). Spirometry was used to capture indices of respiratory function (forced vital capacity % predicted, peak cough flow [PCF]). Validated questionnaires were used to collect information regarding ALS-related bulbar functional status and swallowing-related concerns. Results: Compared to the matched healthy cohort, individuals with ALS demonstrated higher rates of non–E-E respiratory–swallow phase patterning and worse bulbar/swallow dysfunction. Group (ALS), swallow tasks, and PCF were significantly associated with respiratory–swallow phase pattern. Conclusions: These preliminary findings support altered respiratory–swallow phase patterning in ALS. Future work should employ an instrumental assessment to quantify swallowing physiology and elucidate the relationship between perturbed respiratory–swallow coordination and swallowing function.