Gum Chewing Exercise Synchronised With Neuromuscular Electrical Stimulation is Better Than Gum Chewing Exercise Alone for Improving Masticatory Function and Mucosal Moisture in Older Adults With Sarcopenic Dysphagia

BACKGROUND: Gum chewing exercise (GCE) is widely used to improve masticatory function in older adults. Nevertheless, it is necessary to develop new therapeutic methods that exert synergistic effects with GCE. OBJECTIVE: This study aimed to examine the effects of GCE synchronised with neuromuscular electrical stimulation (NMES) on masticatory function and mucosal moisture in older adults with sarcopenic dysphagia. METHODS: This study enrolled 40 older adults with sarcopenic dysphagia. The participants were randomly assigned to the GCE and GCE plus NMES groups. The GCE group underwent GCE using xylitol gum for 30 min/day, 5 days/week for 4 weeks. The GCE plus NMES group performed GCE with NMES on the upper border of the masseter muscle, below the zygomatic bone in the facial area for 30 min/day, 5 days/week, for 4 weeks. The primary outcome measures were the maximum bite force and masseter muscle thickness. The secondary outcome measure was mucosal moisture on the dorsum of the tongue. RESULTS: The GCE plus NMES group showed a significant increase in the maximum bite force, masseter muscle thickness, and saliva secretion compared with the GCE group (p < 0.05, all). CONCLUSION: This study demonstrated that NMES synchronised with GCE was more effective than GCE alone in improving masticatory function and mucosal moisture in older adults with sarcopenic dysphagia.