Tongue Pressure Profile Training for Dysphagia Post Stroke

Overview

People with swallowing impairment experience particular difficulty swallowing thin liquids safely; the fast flow of liquids makes them difficult to control. The tongue plays a critical role in containing liquids in the mouth, channeling the direction of their flow towards the pharynx (throat) and controlling their flow along that channel. The investigators are engaged in a program of research to better understand tongue function in swallowing, particularly with respect to controlling the flow of liquids. In this study the investigators will compare two different tongue-pressure resistance training protocols, to determine whether a protocol that emphasizes strength-and-accuracy or one that emphasizes pressure timing work better for improving liquid flow control in swallowing.

Drinking thin liquids is something that most of us take for granted; yet this task is one that many patients with dysphagia (swallowing impairment) cannot do safely. Instead, these individuals receive liquids in thickened form: thickened juice, thickened coffee… even thickened water. The literature tells us that patients dislike the taste and feel of thickened liquids and find that their thirst is not quenched. Patients on thickened liquids are prone to inadequate fluid intake and dehydration. Many patients are non- compliant and drink thin liquids, despite documented risk for aspiration (i.e., airway invasion) and its consequences. Given these limitations, it is important that dysphagia researchers continue to pursue treatments with the potential to restore safe and functional thin liquid swallowing in people with dysphagia. In the past decade, tongue pressure resistance training has emerged as an innovative treatment for dysphagia. Dr. JoAnne Robbins (University of Wisconsin - Madison)has shown that 8-weeks of intensive tongue pressure resistance training improves tongue strength in healthy seniors and those with dysphagia following stroke. In our lab (the Swallowing Rehabilitation Research Laboratory at the Toronto Rehabilitation Institute), the investigators have studied a variation on Dr. Robbins' treatment called "Tongue Pressure Strength and Accuracy Training". This approach also improves tongue strength and improves aspiration. However, the investigators continue to be bothered by the fact that people with dysphagia post stroke often have difficulty controlling the flow of thin liquids, even after these strength-focused protocols of tongue-pressure training. The investigators have recently completed a study of tongue pressures profiles (strength and timing) in healthy people, which shows that tongue pressures are released more slowly with thin liquids than with thick liquids. This reveals active control of thin liquid flow, and suggests that both the strength and timing of tongue pressure play a role in flow-control. The investigators believe that treatment outcomes may be better if tongue pressure resistance training protocols take both strength and timing into consideration. To this end, the investigators have recently identified a subset of tongue pressure training tasks for which the strength and timing profile of tongue pressure onset and release is similar to that seen in liquid swallowing. The investigators propose that a treatment protocol will have better potential to yield favourable outcomes for thin liquid flow-control if it focuses on such tasks. In this study, the investigators want to determine whether tongue pressure profile training, which addresses both timing and amplitude issues in tongue pressure generation, yields better functional outcomes in swallowing than strength-and-accuracy focused treatment. The investigators will pursue this question in a small randomized prospective trial, building on our prior work in this area. The investigators will recruit 60 new patients with who demonstrate thin liquid flow-control difficulties secondary to stroke. These individuals will be randomized either to tongue-pressure strength-and-accuracy training (TPSAT) or to the novel intervention, tongue-pressure profile training (TPPT). The investigators will study their treatment outcomes after 12 weeks (24-sessions) of treatment.