George Umemoto, Hirokazu Furuya, Yoshio Tsuboi, Shinsuke Fujioka, Hajime Arahata, Miwa Sugahara, Mitsuaki Sakai

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. 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. 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). 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.