Surface electromyographic characteristics of the bilateral submental muscles in dysphagia secondary to unilateral brainstem stroke

Abstract

Objective To observe the surface electromyographic characteristics of the bilateral submental muscles in dysphagia secondary to unilateral brainstem stroke. Methods A total of 25 subjects were recruited.There were 8 stroke patients with dysphagia secondary to a left brainstem stroke and 7 stroke patients with dysphagia secondary to a right brainstem stroke. There were also 10 healthy controls matched in age and gender. The duration and peak amplitude of the submental muscle when swallowing 5 ml of warm water were recorded using a surface electromyograph. Results The average amplitude of the left submental muscle in patients with a left brainstem stroke was significantly longer than that of those with a right brainstem stroke, but no significant differences in average duration were observed. Conversely, the amplitude of the right submental muscle in patients with a right brainstem stroke was significantly longer than that of those with left brainstem stroke, but again there were no significant differences in duration. No significant differences were observed among the healthy controls. The amplitude and duration of both the affected and healthy sides of the patients were of course significantly longer or stronger than those of the healthy controls. Conclusion The swallowing function of the bilateral submental muscles may be impaired among unilateral stroke survivors with dysphagia. The damage on the affected side is more severe than on the opposite side. Key words: Dysphagia; Surface electromyography; Brainstem; Stroke; Submental muscles