Comparison of NMES, tDCS, and TMS Treatments in Post-Stroke Dysphagia

Swallowing safety for liquid boluses will be assessed from videofluoroscopic swallowing recordings using the 8-point Penetration-Aspiration Scale (PAS). Scores range from 1 to 8, with higher scores indicating greater airway invasion and more severe impairment. The change from baseline to post-treatment will be compared among the four intervention groups.

The severity of pharyngeal dysphagia will be assessed from videofluoroscopic swallowing recordings using the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST). DIGEST combines swallowing safety, based primarily on the Penetration-Aspiration Scale, and swallowing efficiency, based on pharyngeal residue, to generate an overall grade ranging from 0 to 4. Grade 0 indicates no pharyngeal dysphagia, while grades 1, 2, 3, and 4 indicate mild, moderate, severe, and life-threatening pharyngeal dysphagia, respectively. Lower scores represent better swallowing function. Change from baseline to post-treatment will be compared among the intervention groups.

Pharyngeal residue will be assessed from videofluoroscopic swallowing recordings using the Bolus Residue Scale (BRS). The scale ranges from 1 to 6 according to the number and location of pharyngeal structures containing residue. A score of 1 indicates no residue, while higher scores indicate residue involving a greater number of pharyngeal structures and therefore worse bolus clearance. Change from baseline to post-treatment will be compared among the intervention groups.

Functional oral intake will be evaluated using the Functional Oral Intake Scale (FOIS). The FOIS is a 7-level ordinal scale ranging from 1, indicating no oral intake, to 7, indicating a total oral diet with no restrictions. Higher scores represent greater functional oral intake and less dependence on tube feeding or dietary modification. Change from baseline to post-treatment will be compared among the intervention groups.

The presence of clinical signs associated with dysphagia will be evaluated using the Toronto Bedside Swallowing Screening Test (TOR-BSST). Each item is rated as pass or fail. Failure on any item results in an overall failed screening result and indicates an increased risk of dysphagia. The number and proportion of participants passing or failing the screening before and after treatment will be evaluated.