Tongue strength and swallowing dynamics in chronic obstructive pulmonary disease

Abstract

Background Swallowing disorders occur in COPD, but little is known about tongue strength and mastication. This is the first assessment in COPD of tongue strength and a test of mastication and swallowing solids (TOMASS). Methods Anterior tongue strength measures were obtained in 18 people with COPD, aged 73±11 years (mean±sd), and 19 healthy age-matched controls, aged 72±6 years. Swallowing dynamics were assessed using an eating assessment tool (EAT-10), timed water swallow test (TWST), and TOMASS. Swallowing measures were compared to an inhibitory reflex (IR) in the inspiratory muscles to airway occlusion (recorded previously in the same participants). Results Tongue strength was similar between COPD and controls (p=0.715). Self-assessed scores of dysphagia EAT-10 were higher (p=0.024) and swallowing times were prolonged for liquids (p=0.022) and solids (p=0.003) in the COPD group. During TWST, ∼30% of COPD group showed clinical signs of airway invasion (cough and wet voice), but none in the control group. For solids, the COPD group had ∼40% greater number of chews (p=0.004), and twofold-higher number of swallows (p=0.0496). Respiratory rate was 50% higher in COPD group than controls (p <0.001). The presence of an IR was not related to better swallowing outcomes, but signs of airway invasion were associated with a delayed IR. Conclusion Dysphagia in stable COPD is not due to impaired anterior tongue strength, but rather swallowing–breathing discoordination. To address dysphagia, aspiration and acute exacerbations in COPD, therapeutic targets to improve swallowing dynamics could be investigated further.