Sensory transcutaneous electrical stimulation improves post-stroke dysphagic patients

Oropharyngeal dysphagia is frequent in stroke patients and increases mortality, mainly because of pulmonary complications. We hypothesized that sensitive transcutaneous electrical stimulation applied submentally during swallowing could help rehabilitate post-stroke oropharyngeal dysphagia by improving cortical sensory motor circuits. Eleven patients were recruited for the study (5 females, 68 ± 11 years). They all suffered from recent oropharyngeal dysphagia (>eight weeks) induced by a hemispheric (n = 7) or brainstem (n = 4) stroke, with pharyngeal residue and/or laryngeal aspiration diagnosed by videofluoroscopy. Submental electrical stimulations were performed for 1 h every day for 5 days (electrical trains: 5 s every minute, 80 Hz, under motor threshold). During the electrical stimulations, the patients were asked to swallow one teaspoon of paste or liquid. Swallowing was evaluated before and after the week of stimulations using a dysphagia handicap index questionnaire, videofluoroscopy, and cortical mapping of pharyngeal muscles. The results of the questionnaire showed that oropharyngeal dysphagia symptoms had improved (p < 0.05), while the videofluoroscopy measurements showed that laryngeal aspiration (p < 0.05) and pharyngeal residue (p < 0.05) had decreased and that swallowing reaction time (p < 0.05) had improved. In addition, oropharyngeal transit time, pharyngeal transit time, laryngeal closure duration, and cortical pharyngeal muscle mapping after the task had not changed. These results indicated that sensitive submental electrical stimulations during swallowing tasks could help to rehabilitate post-stroke swallowing dysphagia by improving swallowing coordination. Plasticity of the sensory swallowing cortex is suspected.