Ann Rehabil Med.  2015 Apr;39(2):199-209. 10.5535/arm.2015.39.2.199.

Changes in Hyolaryngeal Movement and Swallowing Function After Neuromuscular Electrical Stimulation in Patients With Dysphagia

• Lee HY
• Hong JS
• Lee KC
• Shin YK
• Cho SR

• KMID: 2273041
• DOI: http://doi.org/10.5535/arm.2015.39.2.199

Abstract

OBJECTIVE
To investigate immediate changes in hyolaryngeal movement and swallowing function after a cycle of neuromuscular electrical stimulation (NMES) on both submental and throat regions and submental placement alone in patients with dysphagia.
METHODS
Fifteen patients with dysphagia were recruited. First, videofluoroscopic swallowing study (VFSS) was performed before NMES. All patients thereafter received a cycle of NMES by 2 methods of electrode placement: 1) both submental and throat regions and 2) submental placement alone concomitant with VFSS. The Penetration-Aspiration Score (PAS) and the NIH-Swallowing Safety Scale (NIH-SSS) were measured for swallowing function.
RESULTS
During swallowing, hyolaryngeal descent significantly occurred by NMES on both submental and throat regions, and anterior displacement of hyolaryngeal complex was significant on submental placement alone. NMES on submental placement alone did not change the PAS and NIH-SSS. However, NMES on both submental and throat regions significantly reduced the NIH-SSS, although it did not change the PAS. Patients with no brainstem lesion and with dysphagia duration of <3 months showed significantly improved the NIH-SSS.
CONCLUSION
Immediate hyolaryngeal movement was paradoxically depressed after NMES on both submental and throat regions with significant reductions in the NIH-SSS but not the PAS, suggesting improvement in pharyngeal peristalsis and cricopharyngeal functions at the esophageal entry rather than decreased aspiration and penetration. The results also suggested that patients with dysphagia should be carefully screened when determining motor-level NMES.

Keyword

Deglutition; Electric stimulation; Hyoid bone; Larynx

MeSH Terms

Brain Stem
Deglutition Disorders*
Deglutition*
Electric Stimulation*
Electrodes
Humans
Hyoid Bone
Larynx
Peristalsis
Pharynx

Figure

• 

  Fig. 1 The electrode positions relative to hyoid bone and thyroid cartilage. (A) Electrodes placement in both submental and throat regions. The top pair was placed horizontally in the submental region over the region of the mylohyoid muscle above the hyoid bone. The bottom pair was placed on the skin over the thyroid cartilage on either side of the midline over the region of the thyrohyoid muscle medial to the sternocleidomastoid muscle. (B) Electrodes in submental placement alone. Both pairs of horizontally arranged electrode were placed in the skin overlying the submental region.

• 

  Fig. 2 Change in dysphagia rating scale after neuromuscular electrical stimulation. (A) There was no significant difference in the PAS after NMES on both submental and throat area and submental placement alone. (B) Application to both submental and throat regions significantly decreased the NIH-SSS (*p<0.05), in contrast to the finding that submental placement alone did not change the dysphagia rating scores. PAS, Penetration-Aspiration Score; NIH-SSS, National Institutes of Health-Swallowing Safety Scale; NMES, neuromuscular electrical stimulation.

• 

  Fig. 3 Change in dysphagia rating scale according to the presence of brainstem lesion. (A, B) In the PAS, there was no significant difference after NMES on both submental and throat area and submental placement alone regardless of the brainstem lesion. (C) In the NIH-SSS, patients with no brainstem lesion in whom NMES was applied to both submental and throat regions showed significantly decreased scores (*p<0.05), whereas submental placement alone did not change the scores in the same patients. (D) On the other hand, patients with brainstem lesion did not show significant change in the NIH-SSS after NMES in both placement methods. PAS, Penetration-Aspiration Score; NIH-SSS, National Institutes of Health-Swallowing Safety Scale; NMES, neuromuscular electrical stimulation.

• 

  Fig. 4 Change in dysphagia rating scale according to the duration of dysphagia. (A, B) In the PAS, there was no significant difference after NMES on both submental and throat area and submental placement alone irrespective of the duration of dysphagia. (C) In the NIH-SSS, patients whose dysphagia duration was <3 months showed significant decrease in the NIH-SSS after NMES on both submental and throat area (*p<0.05), whereas submental placement alone did not change the scores in the same patients. (D) On the other hand, subjects whose duration of dysphagia was >3 months did not show a significant change in the NIH-SSS after NMES in both placement methods. PAS, Penetration-Aspiration Score; NIH-SSS, National Institutes of Health-Swallowing Safety Scale; NMES, neuromuscular electrical stimulation.

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