Tongue pressure resistance training for swallowing impairment post-stroke: study protocol for a randomized crossover clinical trial

Abstract

Introduction For patients who have suffered a stroke, tongue strength may be decreased compared to healthy individuals. Patients with dysphagia following stroke are more likely to experience aspiration pneumonia, which has been associated with higher mortality rates and medical complications. Research on strengthening the tongue in the stroke population has shown positive effects of a tongue resistance training protocol. Research also suggests that swallow safety, or protection of the airway, may be improved as a result of such interventions, however the mechanism of improvement remains poorly understood, particularly whether improvement is attributed to the intervention alone, or to spontaneous recovery. This study aims to determine what aspects of the swallowing mechanism (response time, movement, etc. of different structures) are directly impacted in order to provide guidance to clinicians using such treatments.Methods and analysis A multi-site, assessor-blinded, randomized crossover trial was designed to determine the effects of a 4-week course of tongue pressure intervention supplemented with home practice in participants who experience dysphagia (PAS of 3 or greater) at baseline. An instrumental evaluation of swallowing (videofluoroscopic swallowing study) is utilized at baseline to determine whether swallowing safety is impaired. Additionally, a requirement for reduced tongue pressures (<40 kilopascals) on all three trials was added in order to target patients who would benefit from this training. Participants are randomized into a delayed treatment group or an immediate treatment group to control for the effects of spontaneous recovery. All participants receive the 4 week treatment consisting of 2 weekly sessions with a speech-language pathologist and complete daily homework plans. Videofluoroscopic swallowing studies are also performed pre and post intervention to quantify the degree of change attributed to the intervention. The study launched in May 2019 and will enroll a maximum of 40 participants.Discussion This study will explore the effects of tongue pressure intervention on swallowing parameters in patients presenting with dysphagia post-stroke. Describing how the intervention effects specific swallowing mechanisms will provide guidance to clinicians using such treatments with this population. Trial registration number ClinicalTrials.gov identifier NCT03969095, published May 31 2019; https://clinicaltrials.gov/ct2/show/NCT03969095?term=NCT03969095&rank=1