Characteristics of tongue and pharyngeal pressure in patients with neuromuscular diseases.

Background: Tongue and pharyngeal pressure is an essential factor associated with the swallowing function; however, little is known about the difference in tongue and pharyngeal pressure between neuromuscular diseases. This study aimed to characterize tongue and pharyngeal pressure in myotonic dystrophy type 1 (DM1), Duchenne muscular dystrophy (DMD), and amyotrophic lateral sclerosis (ALS) patients.

Methods: This study recruited 17 DMD patients, 32 DM1 patients, and 26 ALS patients. They underwent separate measurements of tongue and pharyngeal pressure under videofluoroscopy, swallowing 5 mL of barium water. We measured the largest change in pharyngeal pressure in the hypopharynx and the upper esophageal sphincter (UES) over several swallows.

Results: The mean tongue pressure (TP) was greatest in the DMD group than in the other groups (p<0.01). There was a significant difference in pressure changes in the hypopharynx and UES between the DM1 group and other groups (p<0.01). Significant correlations were observed between pressure change in the UES and the patient's age in the DMD group (R=-0.500, p=0.045) and between pressure change in the hypopharynx and TP in the DM1 group (R=0.421, p=0.016). There was a significant correlation between pressure change in the hypopharynx and disease severity in the ALS group (R=0.435, p=0.030).

Conclusion: Patients with DMD, DM1, and ALS have weakness in the muscles involved in swallowing; however, the results of this study suggested that each disorder has a distinctive profile of impairment in the swallowing function.