Abstract TP150: Kinematic Visual Biofeedback is Best When Training Novel Swallowing Behaviors in Dysphagic Patients After Stroke

Abstract

Introduction: Dysphagia (swallowing impairment) is a common and often life threatening problem after stroke. Submental surface electromyography (ssEMG) visual feedback is a commonly used clinical tool to train novel swallowing maneuvers, even though its effectiveness has been questioned in studies of healthy adults. This study compares the effect of ssEMG and videofluoroscopy (VF) visual biofeedback on hyo-laryngeal accuracy when training the volitional laryngeal closure swallowing maneuver (vLVC) in post-stroke patients with dysphagia. The vLVC maneuver involves swallowing first, then maintaining laryngeal vestibule closure for at least 2 seconds. This study also examines the accuracy of clinician judgements about patient vLVC performance. Hypothesis: Accuracy will be reduced when only ssEMG (non-kinematic) versus VF (kinematic) visual feedback is used to teach the vLVC. Methods: Stroke participants (N=14) underwent 2 study phases. Phase 1: first demonstrated ability to perform the vLVC accurately. Phase 2 was vLVC training. Participants were randomized into three biofeedback groups including the ssEMG Group (ssEMG biofeedback in phases 1 and 2), the VF Group (VF biofeedback in phases 1 and 2), and the Mixed Group (VF phase 1, ssEMG phase 2). A clinician provided real-time, verbal cueing utilizing the assigned visual biofeedback to promote vLVC accuracy. The clinician could only see the assigned type of feedback also seen by the patient, although both VF and ssEMG were recorded for all participants. Results: Both accuracy of vLVC training performance and clinician feedback were worst in the ssEMG group compared to the VF and Mixed Groups (linear mixed models p<0.001). Conclusions: Swallowing airway protection requires precisely timed movements of small, hidden laryngeal and pharyngeal structures. Kinematic feedback may be required to ensure that target swallowing movements are being trained in rehabilitation.