The interaction between breathing and swallowing in amyotrophic lateral sclerosis.

The aim of the study is to determine the association between respiratory swallow patterns in amyotrophic lateral sclerosis (ALS) patients. Furthermore, it aims to clarify the role of the dysphagia limit in defining the relationship between swallowing disorders and respiratory disorders. Functional rating scales were used to describe swallowing and respiratory function. Swallowing was observed using the dysphagia limit. Dysphagia limit is the volume at which a second or more swallows are required to swallow the whole bolus. Laryngeal and chest movement sensors, pulmonary function tests, submental, and diaphragm electromyography activity were used to evaluate the relationship between swallowing and respiratory phase. Of the 27 patients included in the study, 14 were dysphagic and 13 were non-dysphagic. Tests showed normal respiratory function in 11 of the non-dysphagic patients and 3 of the dysphagic patients. There was a high correlation between the dysphagia limit and Amyotrophic Lateral Sclerosis Functional Rating Scale swallowing parameters. Non-dysphagic patients were able to swallow during inspiration but only six patients in the dysphagic group were able to swallow during inspiration. The occurrence of dysphagia in ALS is related to piecemeal deglutition and respiration consistency during swallowing. Detecting the timing of disturbances in the relationship between swallowing and respiration may be a way of identifying dysphagia. Dysphagia limit may be a useful, complementary test for assessing swallowing disturbances in amyotrophic lateral sclerosis.