Ultrasonography as Biofeedback to Increase Muscle Activation During the Mendelsohn Maneuver in Healthy Adults

Abstract

The purpose of this study was to examine the effect of applying real-time ultrasound as visual feedback in addition to verbal instruction/tactile feedback to facility the accuracy of learning the Mendelsohn maneuver. The Mendelsohn maneuver is one of the commonly used swallowing exercises targeting hyolaryngeal elevation and prolonging upper esophageal sphincter opening during swallow. It was hypothesized that the additional visual cueing provided by ultrasound would significantly increase sEMG activity which may be associated with increased duration and extent of hyolaryngeal elevation during the Mendelsohn maneuver as compared to the effect of verbal instruction/tactile feedback alone. A total of twenty-four healthy adults aged between 20 and 59 years were randomly assigned into training with ultrasound biofeedback versus training with verbal instruction/tactile cueing groups. Outcomes were measured via sEMG before and after training. Statistical analysis of the data with three-way repeated measures ANOVA revealed both ultrasound feedback and traditional cueing were effective for teaching the Mendelsohn maneuver. However, there were no significant differences between the two groups in maximum amplitude of sEMG, sEMG duration, and the area under the curve of sEMG signal when performing swallows with the Mendelsohn maneuver. Although the findings do not demonstrate that the addition of ultrasound biofeedback in training will significantly increase the electromyographic outcomes when performing the Mendelsohn maneuverer, it is still an effective and feasible tool for learning a new swallowing maneuver.