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

The Mendelsohn Maneuver (MM) is a therapeutic strategy that targets reduced laryngeal elevation. Both clinicians and clients identify the MM as one of the more difficult interventions to teach and learn. The purpose of this study was to examine the effect of applying real-time ultrasound as visual feedback in teaching the MM to healthy adults. Twenty-four healthy adults were randomized to two-parallel groups. The standard care group (control group) received verbal instruction, verbal reinforcement, and tactile cueing while practicing the maneuver. The experimental group received the same instruction with additional real-time ultrasound as visual biofeedback. Participants completed a single session which consisted of baseline assessment, training, and post-training assessment. Outcomes were submental surface electromyography (sEMG) signal duration, maximum amplitude, and area under the curve. Statistical analysis revealed that training with feedback significantly increased submental sEMG activity during the MM; however, the addition of ultrasound as biofeedback did not significantly increase muscle activation when performing the MM over verbal instruction with verbal/tactile feedback alone. Both groups demonstrated significantly greater muscle activity measured by sEMG when applying the MM. Although the current study did not indicate that adding ultrasound biofeedback was superior to traditional training alone in teaching healthy adults to perform the MM, it does support the clinical use of biofeedback tools for learning swallowing maneuvers. Ultrasound may be a biofeedback option for people with language deficits or differences to learn a swallowing maneuver. Further studies are required to determine the clinical application of ultrasound as biofeedback on people with dysphagia.