Tongue Pressure Profile Training for Dysphagia Post Stroke (TPPT)

• Change in Swallow Response Time for 5 cc thin liquid swallows [ Time Frame: Post treatment (12 weeks) ] [ Designated as safety issue: No ]
  Swallow response time (the time duration between bolus passing the ramus of the shadow of the mandible and onset of hyolaryngeal excursion for airway protection 5cc thin liquid barium boluses in videofluoroscopy. Measures > 350 ms are considered to reflect impairment and a heightened risk of penetration-aspiration. The participant's mean swallow response time will be calculated across a series of 3 X 5 cc swallows and then reduced to a binary score < vs > 350 milliseconds.
  
  

• Penetration-Aspiration Scale score for 5 cc thin liquid swallows [ Time Frame: Post-treatment (12 weeks) ] [ Designated as safety issue: Yes ]
  The Penetration-Aspiration Scale is an 8-point ordinal scale that addresses the depth of airway invasion and response to airway invasion during swallowing. We will measure penetration-aspiration for a series of 3 X 5 cc thin liquid swallows in videofluoroscopy. The participant's worst score will be taken to reflect their swallowing safety. This score will be collapsed into a binary score < vs. > 3 on the scale, reflecting material entering and remaining in or below the supraglottic space (versus transient entry or no entry at all).
  
  
• Changes in tongue-palate pressure amplitude for maximum isometric pressures [ Time Frame: Pre vs. post-treatment comparison ] [ Designated as safety issue: No ]
  We will measure the amplitude of peak tongue-pressure amplitudes on maximum isometric pressure tasks performed using the Iowa Oral Performance Instrument. The mean amplitude across a series of 5 maximum isometric pressure tasks performed with the bulb in a posterior position (flat end aligned with the first molar tooth) will be used to document changes in tongue strength.
  
  

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.