Relationship between tongue thickness and tongue pressure in neuromuscular disorders

Background Few previous studies have objectively evaluated the relationship between tongue volume and tongue weakness in patients with neuromuscular disorders. Aim The present study aimed to show the relationship between tongue thickness and tongue pressure in patients with neuromuscular disorders. Methods A total of 21 Duchenne muscular dystrophy patients, 30 myotonic dystrophy type 1 patients and 33 amyotrophic lateral sclerosis patients were recruited for this study. Tongue thickness was measured using ultrasonography, and defined as the distance from the raphe of the mylohyoid muscle to the tongue dorsum. Maximum tongue pressure was also determined using an oral probe whose small balloon was compressed onto the palate with the tongue. Results Tongue thickness was significantly higher in the Duchenne muscular dystrophy group than in the other groups. The maximum tongue pressure was lower in the myotonic dystrophy type 1 group than the DMD group. A significant correlation between tongue thickness and maximum tongue pressure was found in the amyotrophic lateral sclerosis group, but not in the other groups. Conclusion Ultrasound is an effective tool to assess tongue thickness in patients with neuromuscular disorders. The present results suggested that tongue pressure, which was relevant to tongue thickness, especially in amyotrophic lateral sclerosis patients, was more useful to evaluate swallowing function than kinesiological analysis of tongue movement.