Effect of neuromuscular electrical stimulation combined with effortful swallowing using electromyographic biofeedback on oropharyngeal swallowing function in stroke patients with dysphagia

Abstract

Background: Electromyographic biofeedback (EMG-BF) is known to be an effective therapy for stroke rehabilitation. However, because few studies have investigated the therapy in patients with dysphagia, its effectiveness is not yet clear. This study aimed to investigate the effect of neuromuscular electrical stimulation (NMES) using EMG-BF on swallowing function in stroke patients with oropharyngeal dysphagia. Methods: In this study, 10 patients with dysphagia were recruited. The 1-group, pre−post study design was adopted. All subjects received NMES combined with EMG-BF in the suprahyoid area. Electrical stimulation was provided as a reward when the electrical signal generated by effortful swallowing reached a preset threshold. The intervention was provided for 30 minutes a day, 5 times a week for 4 weeks. The videofluoroscopic dysphagia scale (VDS) and penetration–aspiration scale (PAS) based on the videofluoroscopic swallowing study were used to evaluate the swallowing function. Results: Pre-intervention showed no significant differences in all items of VDS (P > .05). However, there was a statistically significant change in VDS from 13.36 ± 5.94 to 9.36 ± 5.14 (P = .015) in the oral phase, and from 38.36 ± 7.42 to 20.71 ± 14.61 (P = .016) in the pharyngeal phase. The PAS scores showed significant change from 5.14 ± 2.27 to 3.00 ± 1.00 (P = .031). Conclusion: This study demonstrated that the use of NMES combined with EMG-BF had the potential to improve oropharyngeal swallowing in stroke patients with dysphagia.

Effectiveness of Different Application Parameters of Neuromuscular Electrical Stimulation for the Treatment of Dysphagia after a Stroke: A Systematic Review

“…A total of 21 articles were found, of which eleven were focused on experimental researchs [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ] and nine were randomized-controlled trials [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. The methodological characteristics of the analysed studies are shown in Table 2 and, in Table 3 , the characteristics of the interventions applied in them are presented.…”

“…The application of NMES was not conducted using the same parameters in the analysed investigations. Regarding the application frequency, the choice of 80 Hz was the most widely used [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 35 , 36 , 37 , 39 , 40 , 41 , 42 , 45 ], although, in several cases, this parameter was not mentioned [ 34 , 38 , 44 , 46 ] and in another two studies the authors selected lower frequencies (60 [ 47 ] and 30 Hz [ 43 ]). In all cases, the results were statistically significant; even those studies which used lower frequencies obtained significant reductions in oral and pharyngeal transit time [ 47 ], significant decreases in the severity of penetration and aspiration [ 43 ] and significant increases in the level of oral intake and quality of life [ 43 ].…”

“…The impulse time was also a parameter that varied depending on the study analysed. The most frequent duration was 700 μs [ 28 , 29 , 30 , 32 , 33 , 35 ], although there were studies that used shorter (300 μs [ 31 , 40 , 41 ]) and longer durations (300 [ 27 , 36 , 37 ], 700 [ 39 ] and 800 [ 44 ] ms). In all the analysed cases, the results were significantly positive; even the studies that used shorter impulse times detected improvements in the quality of sleep, level of oral intake, presence and severity of penetration and aspiration, and capacity to communicate and swallow (higher elevation of the pharynx, closing of the epiglottis and coaptation of the pharyngeal wall), although more notably in those cases in which NMES was combined with Mendelsohn maneuvers (and other conventional DP treatment techniques) compared to its use as a single treatment technique [ 31 , 40 , 41 ].…”

“…Regarding the intensity of the application, most of the obtained studies were aimed at reaching the motor threshold as the patient’s tolerance to the current increased with the sessions [ 28 , 29 , 30 , 35 , 42 , 43 , 45 , 46 , 47 ]. In contrast, other studies reached the pain threshold of the patient [ 31 ] or aimed to reach a certain level of intensity as the patient’s tolerance increased with each session: up to 7 [ 37 , 38 ], 8.5 [ 32 ], 12.5 [ 41 ], 20 [ 36 ], 25 [ 40 ] and 28 mA [ 37 ].…”

Post-stroke Dysphagia: Recent Insights and Unanswered Questions

“…The most common biofeedback technique used in post-stroke dysphagia therapy is surface electromyography (sEMG). sEMG biofeedback uses two small electrodes placed on the submental muscles to measure the timing and force of the muscle contraction, which is displayed graphically on a screen [ 88 , 89 ]. A recent meta-analysis found that sEMG biofeedback coupled with swallowing maneuvers increased hyoid displacement in post-stroke dysphagia patients when compared with controls [ 88 ].…”