The purpose of this study was to evaluate the effectiveness of the sequential four-channel neuromuscular electrical stimulation system.
As a prospective case-control study, ten healthy subjects and ten patients with dysphagia were prospectively enrolled. Swallowing with and without sequential four-channel neuromuscular electrical stimulation (suprahyoid, infrahyoid muscles) was evaluated via videofluoroscopic swallowing study and high-resolution manometry.
Results showed that the sequential four-channel neuromuscular electrical stimulation significantly improved the videofluoroscopic dysphagia scale during thick-fluid swallowing in patients with dysphagia. Furthermore, the kinematic analysis of videofluoroscopic swallowing study showed a tendency that neuromuscular electrical stimulation reduced duration of hyoid bone movement during thin- or thick-fluid swallowing. The high-resolution manometry parameters—maximal pressure of velopharynx, tongue base, cricopharyngeal pressure, minimal upper esophageal sphincter pressure, area of velopharynx, upper esophageal sphincter activity time, and duration of nadir upper esophageal sphincter—during thin-fluid swallowing were significantly improve in both groups compared with the high-resolution manometry parameters without neuromuscular electrical stimulation.
The sequential four-channel neuromuscular electrical stimulation may help improve the parameters of videofluoroscopic swallowing study, kinematic analysis of the hyoid bone movement, and high-resolution manometry during swallowing. Further investigations are needed to better examine the effects of neuromuscular electrical stimulation in patients with dysphagia.