Level 2 / 11-19 Bank Place
Melbourne Victoria 3000
T 61 3 9642 4899
F 61 3 9642 4922
office@speechpathologyaustralia.org.au
www.speechpathologyaustralia.org.au
Position
Statement
Neuromuscular Electrical Stimulation (NMES)
Copyright © 2008 The Speech Pathology Association of Australia Limited
Disclaimer: To the best of The Speech Pathology Association of Australia Limited’s ("the Association") knowledge,
this information is valid at the time of publication. The Association makes no warranty or representation in relation to
the content or accuracy of the material in this publication. The Association expressly disclaims any and all liability
(including liability for negligence) in respect of use of the information provided. The Association recommends you
seek independent professional advice prior to making any decision involving matters outlined in this publication.
The Speech Pathology Association of Australia Limited
ABN 17 008 393 440
Speech Pathology Australia
Working Party:
Project Officer:
LEWIS Emily
Royal Melbourne Hospital, Royal Park Campus,
Melbourne, Vic
Working party:
BRIFFA Charmaine
Angliss Hospital, Melbourne, Vic
CLARK Kathy Princess Alexandra Hospital, Brisbane, Qld
DILWORTH Cindy
Royal Brisbane and Women’s Hospital, Brisbane, Qld
DOBBRICK Angie
Royal Brisbane and Women’s Hospital, Brisbane, Qld
DUNKIN Liz
Sir Charles Gardiner Hospital, Perth, WA
FITZGERALD Bron
Kids Are Kids! Therapy and Education Centre, Perth, WA
HOLMES Rhonda
Austin Hospital, Melbourne, Vic
MAHONEY Janine
Alfred Hospital, Melbourne, Vic
MILES Rachel War Memorial Hospital, Sydney, NSW
PIGGOTT Claire
Royal Rehabilitation Centre Sydney, NSW
SCHOLES Susan
Royal Brisbane and Women’s Hospital, Brisbane, Qld
SLATTERY Justine
Royal Children’s Hospital, Melbourne, Vic
TOMOLO Gracie
Royal Melbourne Hospital, City Campus, Melbourne, Vic
TOWNSEND Sarah
Balmain Hospital, Sydney, NSW
WEIR Kelly
Royal Children’s Hospital, Brisbane, Qld
This position statement was developed in consultation and discussion with the above listed
clinicians, as a part of a national working party. The working party members contributed to
the project on the basis of their work context. The working party as a whole was considered
to be representative of the range of contexts in which speech pathologists work.
Neuromuscular Electrical Stimulation in dysphagia and related disorders
2
Speech Pathology Australia
Speech Pathology Australia Position Statement
Speech Pathology Australia (the Association) recognises the increasing interest in the use of
Neuromuscular Electrical Stimulation (NMES) for the treatment of dysphagia and related
disorders.
The use of NMES is considered an advanced skill, requiring specialized knowledge and
training.
Speech pathologists are alerted to the limited research and evidence base regarding the
efficacy of NMES in the management of dysphagia and facial paralysis. The current literature
does not adequately address the benefits of the procedure nor its potential harm or long
term effects.
Speech pathologists intending to perform NMES must commit to contributing to the
research and evidence base for NMES. Any application of NMES must be conducted within
a strict quality or research framework.
It is imperative that speech pathologists consult relevant professional colleagues and engage
the formal support of their employing organisation prior to performing NMES.
This position statement has been developed to guide speech pathologists considering or
intending to implement NMES in Australian healthcare contexts. This position statement has
been informed by current available evidence, international position statements, policies and
procedures of international organisations and consensus opinion.
DEFINITION OF NEUROMUSCULAR ELECTRICAL STIMULATION
Neuromuscular Electrical Stimulation (NMES) is defined as ‘the application of electrical
currents to neural tissue for the purpose of restoring a degree of control over an abnormal or
absent body function’ (Ragnarsson & Baker, 2001 p.723).
NMES usually refers to the use of transcutaneous electrical stimulation, where the electrodes
are applied to the skin. When an electrode is inserted into the muscle motor point or body, it
is referred to as percutaneous or implanted stimulation.
In a normal functioning nerve and muscle unit, electric impulses (known as action potentials)
transmit information from the nerve to the muscle. NMES ‘is the process of eliciting an action
potential in a nerve axon through the delivery of an electric charge to an axon’ (Steele,
Thrasher & Popovic, 2007 p.9). If a muscle is innervated by a nerve, then electrical
stimulation will stimulate this nerve and initiate the contraction of a muscle. If the muscle is
dennervated, then the muscle fibres are directly stimulated (Robertson, Ward, Low & Reed,
2006).
The electrical stimulation provided by NMES is different from normal muscle activity in
several important ways, including the method of muscle fibre recruitment, the synchronicity
of individual motor units, and the intensity of stimuli required to produce muscle changes
(Huckabee & Doeltgen, 2007a).
Neuromuscular Electrical Stimulation in dysphagia and related disorders
3
Speech Pathology Australia
DESCRIPTION OF NMES AND RATIONALE FOR THE PROCEDURE
NMES is conducted with the use of specialised equipment that includes a stimulus
generator, electrodes, power source and user control unit (which allows different parameters,
such as the frequency, pulse duration, amplitude, duty cycle and ramping
to be altered by the therapist). Transcutaneous stimulation involves placing small electrodes
on the skin of the face, anterior neck or submental area. The exact placement will vary
dependent upon the specific muscles and nerves being targeted.
NMES can be used in isolation or applied in conjunction with a specific exercise program (for
example completing oral motor exercises whilst using NMES) (Robertson et al, 2006). Each
exercise program will vary dependent upon the client’s pathophysiology. The principles
behind the use of NMES with innervated muscle include strengthening of normal muscle,
increasing muscle endurance, strengthening following disuse atrophy, re-education of
muscle control and increasing the range of joint movement. The principle for using NMES
with denervated muscle is to reduce or prevent muscle atrophy (Robertson et al, 2006).
CONTRAINDICATIONS
Due to limitations in the current evidence base, it is not possible to identify all potential
contraindications to the use of NMES. However, it has been stated that pregnancy and the
presence of indwelling stimulators (i.e. a pace maker) are two contraindications to the use of
NMES (Robertson et al, 2006; Ragnarsson & Baker, 2001). It is also recommended that
NMES not be used over known tumors, damaged or broken skin and superficial indwelling
metal implants (i.e. plate or screws located subcutaneously) (Robertson et al, 2006).
Concerns have also arisen in relation to stimulation of the anterior neck, with the potential to
trigger laryngospasm or inadvertedly stimulate the carotid sinuses (Robertson et al, 2006).
Stimulation of a carotid sinus reflex can lead to bradycardia or vasodilatation, resulting in
hypotension, presyncope, or syncope (Wijetunga, 2005). To date, none of the available
literature regarding the use of NMES in the management of dysphagia and facial paralysis
has reported episodes of laryngospasm or carotid sinus stimulation as a consequence of
treatment. However, the literature advises caution be exercised.
CURRENT LITERATURE
The use of NMES for the management of dysphagia
There continues to be discrepancy and inconsistency in the literature regarding the
effectiveness and safety of NMES in the treatment of dysphagia. The level of evidence for the
majority of the literature is low, varying between case series (i.e. a Level IV on the NHRMC
scale, see Shaw, Sechtem, Searl, Keller, Rawi & Dowdy 2007; Burnett, Mann, Cornell &
Ludlow, 2003; Shrode, 1993), to pseudo-randomised trials (i.e. NHRMC Level III-1, see
Freed, Freed, Chatburn, & Christian, 2001)
The majority of the literature regarding NMES and dysphagia management relates to the use
of transcutaneous electrodes for pharyngeal dysphagia. There is a small body of evidence
suggesting that NMES is an effective therapeutic tool for the treatment of pharyngeal
dysphagia (Freed,et al, 2001; Leelamanit, Limsakul & Geater, 2002; Blumenfeld, Hahn,
LePage, Leonard & Belfasky, 2006; Shaw et al, 2007). A study conducted by Leelamanit,
Limsakul & Geater (2002) indicated improved laryngeal elevation for those clients receiving
NMES. Other studies suggest an overall change in swallowing function as demonstrated by
improvement on swallowing outcome scales (Freed et al, 2001; Shaw et al, 2007). However
a review of these studies reveals limitations in methodology which impact their validity
(Steele, 2004; Logemann, 2007; Huckabee & Doeltgen, 2007b).
There is another body of literature that suggests NMES is not effective in swallowing
rehabilitation and indeed has adverse effects on swallow function (Ludlow, Humbert, Saxon,
Poletto, Sonies & Crujido, 2007; Humbert, Poletto, Saxon, Kearney, Crujido, Wright-Harp,
Neuromuscular Electrical Stimulation in dysphagia and related disorders
4
Speech Pathology Australia
Payne, Jefferies, Sonies, & Ludlow, 2006; Burnett, Mann, Stoklosa & Ludlow, 2005; Suiter,
Leder & Ruarch, 2006; Kiger, Brown & Watkins, 2006). These studies indicate that when
particular electrode placements and parameters are used, there is potential for stimulated
swallows to be ‘less safe’ than non-stimulated swallows (Humbert et al, 2006). Kiger, Brown
& Watkins (2006) found no statistical difference in dysphagia outcomes when using NMES or
traditional swallow therapy such as oral motor exercises, compensatory strategies and
thermal stimulation.
As is the case in the literature promoting NMES, literature questioning the validity of NMES is
limited by methodological issues, including variability in length, frequency and number of
treatment trials (Kiger, Brown, & Watkins, 2006; Humbert et al, 2006), small subject numbers
and mixed aetiology of clients (Ludlow et al, 2007).
The use of NMES for the management of facial paralysis
There are two main articles reporting the use of NMES for the treatment of facial paralysis
(Targan, Alon & Kay, 2000; Farragher, Kidd & Tallis, 1987). Both of these articles report use
of NMES with lower motor neuron facial paralysis; to date, there are no published reports of
the application of NMES with upper motor neuron facial paralysis. These two articles suggest
positive outcomes in using NMES, but the clinical application of both the studies is limited
due to methodological flaws (for example no control group, poor description of the treatment
regime and electrode placements, no follow up of subjects post treatment) and incomplete
statistical analysis.
There are several other published studies on the use of NMES for the treatment of facial
paralysis, but they are also limited by significant methodological constraints and very small
subject numbers (Shrode, 1993; Paniora, 1994; Frach, Osterbauer & Fuhr, 1992). A review of
the evidence base undertaken in Queensland (Watter, 2007) concluded there to be a paucity
of information regarding both the long-term consequences of using NMES, and its effects on
neuronal regeneration in the spontaneous period of recovery of facial paralysis.
Clinical experts in the area of NMES in Australia caution that neuromuscular retraining of the
face is more complex than is often perceived (Cindy Dilworth, personal correspondence,
2008). One of the issues in the treatment of facial paralysis (along with other problems such
as hypertonicity and spasm), is synkinesis. Facial synkinesis is defined as the involuntary
movement of facial muscles that accompanies purposeful movement of another set of
muscles (for example the eye involuntarily closing when smiling) (Chamberlin & Narins, 2005).
Unfortunately, research into the area remains limited and the exact mechanisms of
synkinesis are not well understood.
Summary statement regarding current literature
Evaluation of the current available evidence for the use of NMES in the management of
dysphagia and facial paralysis reveals significant limitations related to methodology, client
groups and reported outcomes. Many authors conclude that further research in the area is
essential to facilitate an increased understanding of the procedure and its efficacy. It is with
this further information that the effectiveness of NMES as a therapeutic tool can be
evaluated.
Neuromuscular Electrical Stimulation in dysphagia and related disorders
5
Speech Pathology Australia
ISSUES
Limited evidence base
There is currently limited evidence to support the use of NMES in the management of
dysphagia and facial paralysis. In addition, the literature on NMES does not address the long
term effects or benefits, nor does it provide guidance regarding the potential for NMES to
cause harm.
Speech Pathology Australia acknowledges the growing interest and use of NMES in clinical
practice and seeks to promote further research into and evaluation of the procedure.
Speech pathologists intending to use NMES are obliged to contribute to the developing
evidence base. Speech pathologists using NMES must do so within a strict quality or
research framework, with explicit workplace support from their employing organisation.
Advanced knowledge and skills required by speech pathologists
Speech pathologists intending to use NMES are required to have a thorough understanding
of a client’s pathophysiology and neuronal recovery pattern. This applies for both the
treatment of dysphagia and facial paralysis.
The use of NMES is an advanced skill. The depth of knowledge required to fully understand
the electrophysiology behind NMES is not currently addressed at Entry Level Undergraduate
or Masters speech pathology courses. Within Australia, those professions using NMES, such
as physiotherapy, have dedicated subjects in Undergraduate and Masters courses to
provide education and training regarding NMES.
Specific skills and knowledge required to conduct NMES may include:
• Knowledge of the principles of electrophysiology,
• Knowledge of parameters such as pulse frequency, pulse duration, amplitude, duty
cycle and ramping,
• Knowledge of how altering a parameter may affect the outcome for a client,
• Knowledge and skill in the assessment and management of dysphagia and facial
paralysis,
• Knowledge of neuronal recovery patterns,
• A thorough understanding of a client’s pathophysiology,
• An ability to accurately diagnose problems such as synkinesis, spasm and
hypertonicity,
• An ability to identify contraindications for use and monitor for adverse outcomes,
• An ability to problem solve when the desired therapeutic outcome does not
eventuate.
Currently, outlining the requirements for credentialing and training of speech pathologists for
the use of NMES is considered premature. Should the developing evidence base indicate
that the application of NMES is effective and safe to be used in clinical practice, then the
issue of credentialing, training and ongoing professional development will be addressed by
the Association.
Experts in NMES agree that a training program should involve an integrated supervised,
problem solving approach underpinned by thorough knowledge and understanding of
anatomy and physiology, the principles of electrotherapy and neuromuscular rehabilitation.
Neuromuscular Electrical Stimulation in dysphagia and related disorders
6
Speech Pathology Australia
SUMMARY
•
•
•
•
•
•
•
•
Speech Pathology Australia recognises the increasing national and international
interest in the use of NMES in the treatment of dysphagia and related disorders.
NMES is an area of advanced skill and knowledge.
There is limited research and evidence base to support the use of NMES in
swallowing rehabilitation and management of facial paralysis.
There is currently inadequate information regarding the potential for NMES to cause
harm or information regarding its long term effects.
Speech pathologists wanting to apply NMES to clinical practice must do so within a
strict quality or research framework, with appropriate support from their employing
organisation, treating medical team and informed consent from the client.
Speech pathologists practicing in NMES are obliged to contribute to the evidence
base regarding NMES in dysphagia and related disorders.
Speech pathologists wanting to apply NMES within a quality or research framework,
must seek support and professional training from a speech pathologist with
experience in NMES. Other appropriately trained professionals such as an
experienced physiotherapist may also be consulted.
Should the developing evidence base support the use of NMES in clinical practice,
then guidelines regarding its use and application and further clarification around the
credentialing and training of speech pathologists will be addressed by the
Association.
Neuromuscular Electrical Stimulation in dysphagia and related disorders
7
Speech Pathology Australia
CITED REFERENCES
Blumenfeld, L., Hahn, Y., LePage, A., Leonard, R., & Belfasky, P. (2006). Transcutaneous electrical
stimulation versus traditional dysphagia therapy: A nonconcurrent cohort study. Otolaryngology Head
and Neck Surgery, 135, 754–757.
Burnett, T., Mann, E., Cornell, S., & Ludlow, C. (2003). Laryngeal elevation achieved by neuromuscular
stimulation at rest. Journal of Applied Physiology, 94, 128–134.
Burnett, T., Mann, E., Stoklosa, J., & Ludlow, C. (2005). Self-triggered functional electrical stimulation
during swallowing, Journal of Neurophysiology, 94, 4011–4018, December.
Chamberlin, S., & Narins, B. (Ed). (2005). Facial Synkinesis. Encyclopedia of Neurological Disorders.
Retrieved 10th June 2008. <http://www.enotes.com/neurological-disorders-encyclopedia/
facial-synkinesis>
Farragher, D., Kidd, G., & Tallis, R. (1987). Eutrophic electrical stimulation for Bell’s Palsy. Clinical
Rehabilitation, 1, 265–271.
Frach, JP., Osterbauer, P.J., & Fuhr, A.W. (1992). Treatment of Bell’s Palsy by mechanical force,
manually assisted chiropractic adjusting and high-voltage electrotherapy. Journal of Manipulative and
Physiological Therapeutics, 15 (9), 596–598.
Freed, M., Freed, L., Chatburn, R., & Christian, M. (2001). Electrical stimulation for swallowing disorders
caused by stroke. Respiratory Care, 46 (5), 466–474, May.
Humbert, I., Poletto, C., Saxon, K., Kearney, P., Crujido, L., Wright-Harp, W., Payne, J., Jeffries, N.,
Sonies, B.,& Ludlow, C. (2006). Effects of surface electrical stimulation on hydro-laryngeal movement
in normal individuals at rest and during swallowing. Journal of Applied Physiology, 101, 1657–1663.
Huckabee, ML., & Doeltgen, S. (2007a) Emerging modalities in dysphagia rehabilitation: neuromuscular
electrical stimulation. The New Zealand Medical Journal, 120, 1-9
Huckabee, ML., & Doeltgen, S. (2007b) Position paper on neuromuscular electrical stimulation in
swallowing rehabilitation. New Zealand Speech Therapists Association
Kiger, M., Brown, C., & Watkins, L. (2006). Dysphagia management: an analysis of patient outcomes
using VitalStim therapy compared to traditional swallow therapy.
Dysphagia, 21 (4), 243–253.
Leelamanit, V., Limsakul, C., & Geater, A . (2002). Synchronised electrical stimulation in treating
pharyngeal dysphagia. Laryngoscope, 112, 2204–2210, December.
Ludlow, C., Humbert, I., Saxon, K., Poletto, C., Sonies, B., & Crujido, L. (2007). Effects of surface
electrical stimulation both at rest and during swallowing in chronic pharyngeal dysphagia, Dysphagia,
22 (1), 1-10.
Logemann, J. (2007). Effects of VitalStim on clinical and research thinking in dysphagia. Dysphagia, 22,
(1),11-12
Paniora, L. (1994). The treatment of Bell’s Palsy using the respond unit. A case study. NZ Journal of
Physiotherapy, Dec, 30–32.
Ragnarsson, K., & Baker, L. (2001). Functional electrical stimulation in persons with spinal cord injury.
In: Gonzalez, E., Myers, S., Edelstein, J., Lieberman, J., & Downey, J, Physiological Basis of
Rehabilitation Medicine (3rd ed), Boston, Butterworth Heinemann.
Robertson, V., Ward, A., Low, J., & Reed, A. (2006). Electrotherapy Explained – Principles and Practice
(4th ed), New York, Butterworth Heinemann Elsevier.
Shaw, G., Sechtem, P., Searl, J., Keller, K., Rawi, T., & Dowdy, E. (2007). Transcutaneous
neuromuscular electrical stimulation (Vital Stim). Curative therapy for severe dysphagia: Myth or reality?
Annals of Otology, Rhinology & Laryngology, 116 (1), 36–44, January.
Neuromuscular Electrical Stimulation in dysphagia and related disorders
8
Speech Pathology Australia
Shrode, L. (1993). Treatment of facial muscles affected by Bell’s Palsy with high voltage electrical
stimulation. Journal of Manipulative and Physiological Therapeutics, 16 (5), 347–352.
Steele, C. (2004). Electrical stimulation of the pharyngeal swallow: Does the evidence support
application in clinical practise? Journal of Speech-Language Pathology and Audiology, 28 (2), 78–84,
Summer.
Steele, C., Thrasher, A., & Popovic, M. (2007). Electrical stimulation approaches to the restoration and
rehabilitation of swallowing: a review. Neurological Research, vol 29 9-15, January.
Suiter, D., Leder, D., & Ruarck, J. (2006). Effects of neuromuscular electrical stimulation on submental
muscle activity Dysphagia, 21 (1), 56–60.
Targan, R., Alon, G., & Kay, S. (2000). Effect of long-term electrical stimulation on motor recovery and
improvement of clinical residuals in patients with unresolved facial nerve palsy. Otolaryngology - Head
and Neck Surgery, 122 (2), 246–252.
Watter, K. (2007). Evidence based review – speech pathology and microfacial stimulation. Queensland
Government, Queensland Health.
Wijetunga, N (2005). Carotid Sinus Hypersensitivity. Retrieved 6th May 2008.
http://www.emedicine.com/med/TOPIC299.HTM
ADDITIONAL REFERENCES:
Broniatowski, M., Vito, K., Shah, B., Shields, R., & Strome, M. (1997). Artificial control of glottic
adduction for aspiration by orderly recruitment in the canine, Dysphagia, 12 (2), 93–97.
Crary, M., Carnaby-Mann, G., & Faunce, A. (2007). Electrical stimulation therapy for dysphagia:
descriptive results of two surveys. Dysphagia 22 (3),165–173.
Diels, J. (2000). Facial Paralysis: Is there a role for a therapist? Facial Plastic Surgery, 16 (4), 361–364.
Gittens, J., Martin, K., Sheldrick, J., Reddy, A., & Thean, L. (1999) Electrical stimulation as a therapeutic
option to improve eyelid function in chronic facial nerve disorders. Investigative Ophthalmology &
Visual Science, 40 (3), 547–554.
Hamby, S., Rothwell, J., Aziz, Q., Singh, K., & Thompson, D. (1998). Long-term reorganization of
human motor cortex driven by short term sensory stimulation. Nature Neuroscience, 1 (1), 64-68, May.
Park, C., O’Neill, P., & Martin, D. (1997). A pilot exploratory study of oral electrical
stimulation on swallow function following stroke: An innovative technique. Dysphagia, 12, 161-166.
Power, M., Fraser, C., Hobson, A., Rothwell, J., Mistry, S., Nicholson, D., Thompson, D., & Hamdy, S.
(2003). Changes in pharyngeal corticobulbar excitability and swallowing behaviour after oral
stimulation. American Journal of Gastrointestinal Liver Physiology, 286, G45–50.
Power, M., Fraser, C., Hobson, A., Sing, S., Tyrrell, P., Nicholson, D., Turnbull, I., Thompson, D., &
Hamdy. S. (2006). Evaluation oral stimulation as a treatment for dysphagia after stroke. Dysphagia 21,
(1), 49–55.
Power, M., Hamdy, S., Singh, S., Tyrrell, P., Turnbull, I., & Thompson, D. (2007).
Deglutitive laryngeal closure in stroke patients. Journal of Neurology, Neurosurgery and Psychiatry, 78,
141–146.
Shafshak, T. (2006). The treatment of facial palsy from the point of view of physical and rehabilitation
medicine. Europa Medicophysica, 42, 41–47, March.
Neuromuscular Electrical Stimulation in dysphagia and related disorders
9