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Table of Contents    
Year : 2017  |  Volume : 65  |  Issue : 4  |  Page : 743-745

The effect of sensory-level electrical stimulation of the masseter muscle in early stroke patients with dysphagia

1 Department of Neurology, Govind Ballabh Pant Institute of Postgraduate Medical Education and Research-GIPMER (Delhi University), New Delhi, India
2 Department of Microbiology, Janakpuri Superspecialty Hospital Society, Janakpuri, New Delhi, India

Date of Web Publication5-Jul-2017

Correspondence Address:
Man Mohan Mehndiratta
Department of Neurology,Govind Ballabh Pant Institute of Postgraduate Medical Education and Research-GIPMER (Delhi University), New Delhi - 110 002
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/neuroindia.NI_522_17

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How to cite this article:
Mehndiratta MM, Gupta P, Kaur M. The effect of sensory-level electrical stimulation of the masseter muscle in early stroke patients with dysphagia. Neurol India 2017;65:743-5

How to cite this URL:
Mehndiratta MM, Gupta P, Kaur M. The effect of sensory-level electrical stimulation of the masseter muscle in early stroke patients with dysphagia. Neurol India [serial online] 2017 [cited 2020 Dec 4];65:743-5. Available from:

Dysphagia is a disorder of deglutition affecting the oral, pharyngeal, and esophageal phases of swallowing. Oropharyngeal dysphagia is an abnormality in the swallowing physiology of the upper digestive tract, is seen frequently after stroke, and is associated with malnutrition, dehydration, pulmonary infections, prolonged hospital stay, and especially aspiration pneumonia. There is an increased risk of aspiration pneumonia after post-stroke dysphagia in 43–70% of patients, associated with a mortality rate of 45%. Other than aspiration pneumonia, it also causes dehydration, malnutrition, and increased length of hospital stay, all of which lead to a poor functional recovery.[1] Up to one-third of stroke patients suffer from pneumonia and this increases the morbidity and mortality of the patients. Intubation is needed after respiratory failure from stroke in up to 6% of patients suffering from an ischemic stroke and in 30% of patients having a haemorrhagic stroke.[2]

Stroke due to cerebral lesions may interrupt voluntary control of mastication and bolus transport during the oral phase. Cortical lesions involving the precentral gyrus produce contralateral impairment in facial, lip, tongue motor control, and contralateral compromise in the pharyngeal peristalsis. Brain stem lesions affect the sensation of the mouth, tongue, and cheek, timing in the trigger of the pharyngeal swallow, laryngeal elevation, glottis closure, and cricopharyngeal relaxation.[1] The present study highlights that electrical stimulation plays a role in partial/complete recovery of impaired muscle function involved in swallowing and functional recovery of the affected hemisphere by the restoration mechanism. This is first study in literature which is aimed at evaluating the effects of sensory-level electrical stimulation (SES) to bilateral masseter muscles in early stroke patients with dysphagia. This study was conducted at the Physical Medicine and Rehabilitation Clinic of Ankara, Turkey between 2013 and 2015. Ninety-eight patients with dysphagia within the first month after ischemic stroke were included in the study.[3]

Patients were evaluated by bedside screening tests (Bedside Dysphagia Score, Neurological Examination Dysphagia Score, Total Dysphagia Score, and Mann Assessment of Swallowing Ability test) and the flexible fiberoptic endoscopic evaluation of swallowing (FEES) methods. All patients were included in a traditional swallowing therapy. Patients were divided into two groups designated as the “stimulation group” and the “sham group.” SES was applied to bilateral masseter muscles. Evaluation parameters were compared between the groups before and after therapy. Statistical analysis was done using Friedman test, Wilcoxon Signed Rank test, Mann–Whitney U test, and Fisher exact test. There was a significant improvement in the dysphagia severity scores evaluated by bedside screen tests and FEES in cognitive and total functionality levels, the only exception being the motor functional independence level in the stimulation group. In the sham group, there were no significant changes in the evaluation parameters. SES applied to bilateral masseter muscles may provide an effective treatment for both dysphagia and cognitive function in early stroke patients. Functional treatment of dysphagia is based on restoration, compensation, and adaptation mechanisms. The masseter muscle is selected for electrical stimulation because it is a big muscle which is easily accessible and application of stimulation to its surface is practically applicable. Moreover, it has an activity during both oral and pharyngeal phases. There was a significant improvement of dysphagia severity in the SES plus traditional therapy group compared to the traditional group.

In a study done by Ianessa A et al., stimulation by surface electrical stimulation was done on the suprahyoid muscles (anterior belly of digastric, mylohyoid, and geniohyoid), which pull the hyoid bone upward and forward, a motion that is used for swallowing. Percutaneous bilateral stimulation of the mylohyoid muscle induces displacement of the larynx of ~50% during swallowing. The unavoidable stimulation of all muscles within the electrical field might not pose a limitation if all muscles in the field serve the same function.[4]

Similarly, in another study, the effects of neuromuscular electrical stimulation (NMES) combined with the traditional dysphagia therapy (TDT) versus the traditional dysphagia therapy in acute/subacute ischemic stroke patients with moderate to severe dysphagia, were assessed by the video fluoroscopic swallowing study (VFSS). It was concluded that an early application of NMES combined with TDT showed a positive effect in acute/subacute ischemic stroke patients with dysphagia. These results indicated that the early application of NMES could be used as a supplementary treatment of TDT for acute/subacute dysphagic stroke patients by improving their swallowing coordination.[5]

Falsetti A et al., studied 151 patients in a neurorehabilitation centre who had developed ischemic or haemorrhagic stroke. 62 out of 151 patients (41%) were diagnosed with dysphagia. 49 patients (79% of the clinically dysphagic patients) underwent a video fluoroscopy (VFS), out of which six patients had a normal VFS finding. The correlation between the clinical and VFS diagnosis of dysphagia was significant. Dysphagia occurs in more than a third of patients with stroke admitted to rehabilitation centres. The dysphagia was not influenced by the type of stroke. Clinical assessment demonstrated a good correlation with VFS. Cortical stroke of the nondominant side was associated with dysphagia and subcortical nondominant stroke showed a reduced frequency of dysphagia.[6]

Rehabilitation of pharyngeal phase impairments presents as the challenge for clinicians, and will continue to do so. More challenges ensue since pharyngeal swallowing is not readily seen without imaging technology (i.e., video fluoroscopy or fiberoptic endoscopic evaluation of swallowing). Therefore, the greatest challenge for the clinicians and researchers is to determine the parameters of improvement or deterioration for a given treatment. Efficacy studies are challenging, costly and time intensive due to the need for a robust control group, a strict randomization process, researcher and patient blinding, and a large, homogeneous sample of patients. The effectiveness of electrical stimulation in stroke patients with dysphagia may be enhanced by increasing the muscle activity. Stimulation of the suprahyoid and infrahyoid muscles, which are active during the pharyngeal phase, were preferred as they increased the hyolaryngeal elevation, thus being helpful in preventing aspiration. Electrical stimulation has been shown to be effective primarily in chronic stroke patients with dysphagia in uncontrolled studies when applying electrical stimulation alone at different intensities. However, in some of the comparison studies, it has been reported that traditional therapies such as thermal tactile stimulation and modifications, as well as electrical stimulation, were both equally effective. In order to ensure a sufficient control of swallowing, the oral phase is also essential for the initiation and continuation of swallowing, as well as for the maintenance of the neural process. [Table 1] illustrates some of the important studies applying stimulation therapies to patients of stroke with dysphagia [11].
Table 1: Published studies of stimulation therapies in patients of stroke with dysphagia

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  References Top

Martino R, Foley N, Bhogal S, Diamant N, Speechley M, Teasell R. Dysphagia after stroke: Incidence, diagnosis, and pulmonary complications. Stroke 2005;36:2756-63.  Back to cited text no. 1
Armstrong JR, Mosher BD. Aspiration pneumonia after stroke intervention and prevention. Neurohospitalist 2011;1:85-93.  Back to cited text no. 2
Humbert IA, Michou E, MacRae PR, Crujido L. Electrical stimulation and swallowing: How much do we know? Semin Speech Lang 2012;33:203-16.  Back to cited text no. 3
Umay EK, Yaylaci A, Saylam G, Gundogdu I, Gurcay E, Akcapinar D, et al. The effect of sensory-level electrical stimulation of the masseter muscle in early stroke patients with dysphagia: A randomized controlled study. Neurol India 2017;65:734-42.  Back to cited text no. 4
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Lee KW, Kim SB, Lee JH, Lee SJ, Ri JW, Park JG. The effect of early neuromuscular electrical stimulation therapy in acute/subacute ischemic stroke patients with dysphagia. Ann Rehabil Med 2014;38:153-9.  Back to cited text no. 5
Falsetti P, Acciai C, Palilla R, Bosi M, Carpinteri F, Zingarelli A, et al. Oropharyngeal dysphagia after stroke: Incidence, diagnosis, and clinical predictors in patients admitted to a neurorehabilitation unit. J Stroke Cerebrovasc Dis 2009; 18:329-35.  Back to cited text no. 6
Gallas S, Moirot P, Debono G, Navarre I, Denis P, Marie JP, et al. Mylohyoid motor-evoked potentials relate to swallowing function after chronic stroke dysphagia. Neurogastroenterol Motil 2007;19:453-8.  Back to cited text no. 7
Lim KB, Lee HJ, Lim SS, Choi YI. Neuromuscular electrical and thermal-tactile stimulation for dysphagia caused by stroke: A randomized controlled trial. J Rehabil Med 2009;41:174-8.  Back to cited text no. 8
Bülow M, Speyer R, Baijens L, Woisard V, Ekberg O. Neuromuscular electrical stimulation (NMES) in stroke patients with oral and pharyngeal dysfunction. Dysphagia. 2008;23:302-9.  Back to cited text no. 9
Ludlow CL, Humbert I, Saxon K, Poletto C, Sonies B, Crujido L. Effects of surface electrical stimulation both at rest and during swallowing in chronic pharyngeal dysphagia. Dysphagia. 2007;22:1-10.  Back to cited text no. 10
Freed ML, Freed L, Chatburn RL, Christian M. Electrical stimulation for swallowing disorders caused by stroke. Respir Care 2001;46:466-74.  Back to cited text no. 11


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