Introduction
dysphagia, stroke, Dysphagia
DYSPHAGIA, STROKE, DYSPHAGIA, CONTRACTIONS
Dysphagia is one of the most common and serious problems in patients with stroke and its prevalence ranges from 37 to 78%The 2-channel NMES, one of the most common therapeutic methods for dysphagia, is known to strengthen swallowing-related muscles by motor stimulation and facilitating the swallowing reflex through sensory stimulationOur previous study demonstrated that the suprahyoid muscles are activated approximately 150-350 ms earlier than the infrahyoid muscles. These sequential contractions of the swallowing-related muscles cause a circular movement of the hyoid bone during normal swallowingIn our previous structured studies, the sequential 4-channel NMES showed significant compensatory effects in clinical and kinematic parameters during swallowingHowever, the mechanism by which clinical improvement in swallowing occurs when 4-channel NMES is used has not yet been fully elucidated. The videofluoroscopic swallowing study (VFSS) is considered the gold standard evaluation of dysphagia, and a kinematic analysis of VFSS data can provide quantitative information about the hyoid movement and bolus, detecting subtle abnormalities of swallowingTherefore, a clearer understanding of how the sequential 4-channel NMES shows the rehabilitative effectiveness is needed. The aim of this study was to investigate the mechanism of the rehabilitative effects of the sequential 4-channel NMES using kinematic analysis of the hyoid bone movement, using data from a randomized controlled trial