Rehabilitation Exercise for Dysphagia Subsequent to Stroke

Swallowing problems affect as many as 40% of adults over age 60. Serious consequences are suffered by the numerous patients with neuromuscular deficits secondary to stroke. Patients with dysphagia subsequent to stroke face risk of death from pneumonia, perhaps the most serious sequelae of dysphagia, with malnutrition and dehydration also dire secondary consequences. If stroke patients survive, they require longer hospital stays and nursing home placements with diminished rehabilitation potential. Despite these devastating influences that dysphagia secondary to stroke has on health, evidence supporting the effects of specific interventions on swallowing outcomes in this population is sparse.

Neural plasticity is the mechanism by which the damaged brain relearns "lost behavior" in response to rehabilitation. A goal of this proposal is to implement several principles of exercise and neural plasticity (specificity, repetition, and intensity) in a clinically justifiable manner so they may be used to guide clinical research and ultimately practice. To that end, we will determine how neuromuscular changes affect swallowing outcomes in response to 3 unique 8-week exercise interventions compared with a sham hand (control) exercise group.

The main hypothesis is that after 8 weeks of intense progressive rehabilitation exercise with feedback - lingual press (high-intensity, oral, non-swallowing) stroke patients with dysphagia will show swallowing improvement (defined as an improved score on the Penetration/Aspiration Scale and/or the Residue Scale in the absence of worsening in the other average score) to a greater extent than subjects who perform natural swallowing (low-intensity swallowing) exercises or the sham (control) exercise group. This hypothesis will be tested by 3 discrete objectives: Objective 1: Compare outcomes of four different 8-week exercise interventions among dysphagic stroke patients; Objective 2: Characterize bolus flow, swallowing biomechanics, lingual anatomy and swallowing function of stroke patients through initial calculation of multi-dimensional swallowing profiles pre-intervention and comparison of these profiles post-intervention; and Objective 3: Determine the most appropriate dose of treatment between 4 and 8 weeks for study subjects.

We will randomize 200 men and women post-stroke into four groups (50 subjects per group). Subjects will be randomized into one of four groups, to identify treatment outcomes. The exercise interventions include (a) lingual press (high-intensity, oral, non-swallowing) (b) effortful swallowing (high-intensity swallowing); and (c) natural swallowing (low intensity swallowing), compared with (d) a non-oral sham (control) exercise. All exercises will involve 2 sets of 10 repetitions performed 3 times a day on 3 non-consecutive days per week.

For Objectives 1 and 2 at baseline, week 4, and week 8, each subject will complete simultaneous videofluoroscopic and lingual pressure measures to calculate measures of bolus flow and swallowing biomechanics, which comprise 1) direction (average Penetration/Aspiration Scale Score), completeness (average Residue Scale Score), and duration in msec; 2) isometric and swallowing pressures; and 3) duration and extent of hyolaryngeal excursion and opening of the upper esophageal sphincter. At each of the 3 timepoints, each subject also will complete magnetic resonance imaging (MRI) to measure stroke lesion volume, lingual volume, and lingual tissue differentiation as well as complete swallowing-specific quality of life and dietary questionnaires. For Objective 3, subjects will complete all measures at baseline and weeks 4 and 8 to determine when the most benefits are made during the course of exercise. Knowledge of the dose response will allow for more accurate prescription of the clinical programs.