Effect of Localized Muscle Vibration on Oral and Swallowing Pressure in Patients with Dysphagia Following Stroke

This study examined the effects of vibratory stimulation on swallowing-related muscle strength in patients with dysphagia due to stroke, using three types of stimulators and a systematic exercise program. This study was conducted in two stages. In Experiment 1, we examined the effects of three types of vibratory stimulation on the pressure of the tongue and lips (N = 23). In Experiment 2, the effect of submental vibratory stimulation applied during the effortful swallowing (ES) exercise program-consisting of five sets-on swallowing pressure, was examined (N = 37). Vibratory stimulation was applied to the corresponding muscles for 1 min immediately prior to measuring isometric peak pressure or swallowing pressure of the tongue and lips. In Experiment 1, the electric toothbrush showed a limited increase in strength in two tongue-related variables, while the mini-massager and customized vibratory stimulator showed significant increases in strength in all five variables related to tongue and lip pressure (p < 0.05). In Experiment 2, it was found that vibration applied to the submental area for 1 min before each set of ES exercises, consisting of 10 repetitions, significantly increased oral swallowing pressure. This study shows the following preliminary results, which are encouraging and require replication: vibratory stimulation applied to swallowing-related muscles can significantly increase their strength in the short term. Further research through larger trials is necessary to confirm efficacy, determine optimal stimulation parameters, and evaluate effects on functional swallowing.