The Effects of Contrast Medium on Food Viscosity and Muscle Activity of the Submental Muscle Group

Abstract

A videofluoroscopic swallowing study (VFSS) is utilized for diagnosis of dysphagia or to determine dysphagia diets. For the evaluation of swallowing function via VFSS, contrast medium needs to be added to the food. The purpose of this study was to assess the effects of contrast medium on food viscosity and the muscle activity of the submental muscle group. Viscosity measurements were performed using a viscometer and a line spread test (LST), after adding contrast medium into water, yogurt, and porridge to 0%, 12.5%, 25.0%, and 37.5% v/v concentrations. Surface electromyography (sEMG) was performed on 20 healthy adults by attaching EMG electrodes to the submental muscle group. Diet consisted of non-contrast medium food and food containing 37.5% v/v contrast medium. There were significant differences in viscometer and LST results between non-contrast medium food and food with contrast medium (p < 0.001). There was a significant negative correlation between viscometer and LST outcomes (water r = - 0.889, p < 0.001; yogurt r = - 0.952, p < 0.001; porridge r = - 0.837, p < 0.001). Finally, there was a significant difference in muscle activity between non-contrast medium water (2.5 cc) and water containing contrast medium 37.5% v/v (2.5 cc) (p = 0.025). These findings suggest that, when performing VFSS, clinicians should consider changes in food viscosity due to contrast medium in order to provide accurate diagnoses and dysphagia diet plans.