Do We Know the Long-Term Effects of the Most Popular Traditional Swallow Maneuvers on the Submental Muscles?

Background: Various trainings focus on the submental muscles (SMs) for dysphagia rehabilitation because of their importance for swallowing safety and efficiency. According to the current literature, swallow-specific tasks may be optimal exercises for dysphagia. The effortful swallow (ES) and the Masako maneuver (MM) are the most commonly used swallow-specific tasks in the clinical settings for dysphagia for years, but long-term effects for these trainings is insufficient.

Objectives: This study aims to investigate and compare the effects of ES and MM on SM activity, strength and thickness.

Methods: Thirty-seven healthy adults were randomised to ES, MM and control groups, and ES and MM groups completed 6 weeks of swallowing training. Participants in both training groups performed a total of 120 swallows in each session, while control group did not participate in any swallowing training. Surface electromyography was used to evaluate SM activity, digital dynamometer for SM strength and ultrasonography for SM thickness.

Results: Both trainings did not change SM activity (p > 0.05), but increased SM strength (p < 0.05). MM increased the thickness of all SM (p < 0.05), and ES increased the thickness of mylohyoid (right, left) and digastric muscle (right) (p < 0.05), and there was no change in all evaluation parameters in the control group (p > 0.05). Also, trainings were not superior to each other in any parameter (p > 0.05).

Conclusion: The results of this study provided new evidence to the literature to show that ES and MM trainings are effective for improving SM strength and thickness. Considering that SM is important in terms of swallowing safety and effectiveness, it is thought that both trainings may be promising by increasing the strength and mass of SM, especially in individuals with reduced SM strength and mass.