Functional Lingual Pressure Thresholds for Swallowing Safety and Efficiency Impairments in Amyotrophic Lateral Sclerosis

Abstract

Although reductions in lingual strength are reported in individuals with amyotrophic lateral sclerosis (ALS) that are associated with dysphagia; determination of a functional lingual pressure threshold (FLPT) has not yet been established. The present study therefore sought to identify an FLPT for impaired swallowing safety and efficiency in individuals with ALS.Thirty individuals with ALS completed a standardized videofluoroscopic swallowing examination and maximum anterior isometric lingual pressure testing using the Iowa Oral Performance Instrument. Duplicate, blinded ratings of the validated Penetration-Aspiration Scale (PAS) scores and Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) were performed. Binary classifications of safety (unsafe: PAS: ≥ 3) and efficiency (inefficient: ≥ 3% worst total pharyngeal residue) were derived. Descriptives and receiver operating characteristic curve analyses (AUC, sensitivity, specificity) were performed.Unsafe and inefficient swallowing were instrumentally confirmed in 57% and 70% of ALS patients, respectively. Across the entire cohort, the mean maximum lingual physiologic capacity was 32.1 kilopascals ('kPa'; SD: 18.1 kPa). The identified FLPT for radiographically confirmed unsafe swallowing was 43 kPa (sensitivity: 94%, specificity: 62%, AUC 0.82, p = 0.003). FLPT for inefficient swallowing was 46 kPa (sensitivity: 86%, specificity: 56%, AUC = 0.77, p = 0.02).These data provide preliminary FLPT data in a small cohort of individuals with ALS that need to be further investigated in larger cohorts to inform clinical screening practices.

Keywords: Amyotrophic lateral sclerosis; Deglutition; Deglutition disorders; Functional reserve; Lingual pressure.