The Effect of Four-Channel Neuromuscular Electrical Stimulation on Swallowing Kinematics and Pressures: A Pilot Study

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.