Compensatory Effects of Sequential 4-Channel Neuromuscular Electrical Stimulation for the Treatment of Acute, Subacute, and Chronic Dysphagia in a Prospective, Double-Blinded Randomized Clinical Trial

Abstract

Background. The precise mechanism of 2-channel neuromuscular electrical stimulation (NMES) treatment is unknown, and controversy remains over its efficacy. The sequential 4-channel NMES was newly developed based on normal contractile sequences of swallowing-related muscles. Objective. To assess the clinical efficacy of sequential 4-channel NMES during swallowing. Methods. In this prospective RCT, 52 inpatients with dysphagia (acute, subacute, and chronic state) after stroke, brain tumor, or encephalitis were enrolled. Participants who underwent a videofluoroscopic swallowing study (VFSS) and clinical evaluation were enrolled and were randomly assigned to the 4-channel NMES or sham group. The 4-channel NMES and sham groups swallowed thin and honey-like fluids under NMES (sequential stimulation on suprahyoid and infrahyoid) and sham stimulation, respectively. The procedures were evaluated with the VFSS. Pre- and post-treatment evaluations were performed with the videofluoroscopic dysphagia scale (VDS), penetration–aspiration scale (PAS), Likert scale, and kinematic analysis. Results. The 4-channel NMES group showed significantly greater improvements than the sham group with respect to oral VDS, pharyngeal VDS, total VDS, and PAS ( P < .05). Furthermore, the Likert scale for satisfaction, easiness, and discomfort for swallowing showed favorable results for the 4-channel NMES group ( P < .05). In the kinematic analysis, the peak speed point, distance, and velocity of hyoid movement were significantly greater in the 4-channel NMES group ( P < .05). Conclusions. Sequential 4-channel NMES activating the suprahyoid, thyrohyoid, and other infrahyoid muscles during swallowing showed significant clinical improvement with respect to VDS, PAS, and kinematic analysis. Therefore, sequential 4-channel NMES is a potential new functional electrical stimulation system for the treatment of dysphagia.

Kinematic mechanism of the rehabilitative effect of 4-channel NMES: post-hoc analysis of a prospective randomized controlled study

“…In our previous structured studies, the sequential 4-channel NMES showed significant compensatory effects in clinical and kinematic parameters during swallowing 12 . Moreover, in a recent randomized controlled study comparing rehabilitative effects of the sequential 4-channel NMES to the 2-channel NMES, the 4-channel NMES showed significant clinical improvement in penetration-aspiration scale and videofluoroscopic dysphagia scale scores.…”

Physiotherapy Intervention in Dysphagia Among Post Stroke Patients-a Narrative Review

“…Given that No negative consequences were seen during the study, 4-channel NMES appears to hold the position of secure and well-absorbed dysphagia treatment option. Thus, a novel therapeutic approach for the method of compensation in dysphagic patients is consecutive 4-channel NMES 45) .…”

The Thyrohyoid Muscle: A Crucial Player in Deglutition and Vocalization

“…Optimal electrode placement for TNMES should target suprahyoid muscles or both suprahyoid and thyrohyoid muscles (Doan et al, 2022). Sequential fourchannel TNMES targeting suprahyoid, thyrohyoid, and other infrahyoid muscles has also shown significant clinical improvement in dysphagia treatment in terms of the videofluoroscopic dysphagia scale, penetration-aspiration scale (PAS), and kinematic analysis, highlighting the potential of this novel functional electrical stimulation system (Lee et al, 2021).…”