The effects of neuromuscular electrical stimulation on swallowing functions in stroke patients with dysphagia: Single blind randomized controlled trial

Objective: To evaluate the effect of neuromuscular electrical stimulation (NMES) treatment on swallowing functions, severity of dysphagia-related symptoms, swallowing and voice- related quality of life in stroke patients with dysphagia, and to examine the changes in dysphagia imaging findings after treatment. Patients and Methods: Thirty-four stroke patients with dysphagia were included in our prospective, randomized, controlled, and single-blind study, and the patients were randomized into two groups. In our study, traditional dysphagia therapy (TDT) was applied to the control group for 3 consecutive weeks, 5 days a week for 45 minutes a day. TDT for 45 minutes a day and 45 minutes of NMES was applied to the study group 5 days a week for 3 consecutive weeks. Before treatment, after treatment, and 3 months after treatment patients were evaluated with the Functional Oral Intake Scale (FOIS), Eating Assessment Tool-10 (EAT-10), Swallowing Quality of Life Questionnaire (SWAL-QOL), Voice-Related Quality of Life (V-RQOL) questionnaire, and Visual Analogue Scale (VAS). Fiberoptic endoscopic evaluation of swallowing (FEES) and laryngestroboscopic evaluation were performed before and after treatment. Results: Significant improvement was achieved after treatment in FOIS, EAT-10, SWAL-QOL, VRQOL and VAS levels in both groups compared to before treatment, and there was no difference between the two groups; in addition, improvements were maintained at 3 months after treatment. Significant improvement was achieved in both groups in terms of leakage, penetration and aspiration scale (PAS) and residue levels in FEES performed with low and high volume fluid after treatment compared to before treatment. There was no difference between the groups in terms of changes in these parameters. Significant improvement was achieved in the level of leakage and PAS in the TDT-NMES group compared to the before treatment levels in FEES performed with semi-solid food after treatment. There was no significant improvement in these parameters in the TDT group. In FEES performed with semi-solid food after the treatment, significant improvement was achieved in both groups compared to the before treatment residue levels. There was no difference between the groups in terms of changes in this parameter. There was no improvement in PAS and residue levels in either group compared to before treatment in FEES performed with solid food after treatment. In FEES performed with solid food after the treatment, significant improvement was achieved in both groups compared to the before treatment leakage levels. There was no difference between the groups in terms of changes in this parameter. There was no significant change in laryngestroboscopic evaluation parameters and build-up phenomenon after treatment in both groups compared to before treatment. Conclusion: With the application of NMES added to TDT and TDT, improvement was achieved in the swallowing functions, the severity of dysphagia-related symptoms, swallowing and voice-related quality of life values, and it was found that the gains obtained with the treatment continued in the 3rd month. The leakage and PAS levels that occurred with semi-solid food improved significantly only in the group that was applied NMES in addition to TDT. It has been shown that TDT is effective on dysphagia rehabilitation in stroke patients, and adding NMES to TDT may contribute to some functions of swallowing. There is a need for clinical studies on this subject that include larger numbers of patients and longer follow-up periods. Volunteers included in studies on this subject should be selected from special patient groups according to their stroke-related characteristics. In this way, the patient group that benefits most from NMES can be determined. Keywords: stroke, dysphagia, rehabilitation, neuromuscular electrical stimulation