Electrical stimulation (e-stim), most people are familiar with the term. It has become a mainstay in many physiotherapy practices, but what actually is it? Did you know there are actually many different types?
What is e-stim?
E-stim is an umbrella term for various different electrotherapy devices with different intervention goals. Of the most commonly used are Neuromuscular Electrical Stimulation (NMES), Transcutaneous Electrical Nerve Stimulation (TENS) and Inferential Stimulation (IFT). Despite these devices conducting electrical currents through the body via electrodes on the skin, they are in fact used to treat different things and thus their practical application varies .
NMES is used with the primary outcome to maintain strength and flexibility in order to restore, maintain and improve function [1,2]. Normally our brain sends messages to our muscles to initiate contractions. After muscular injuries, our muscle’s ability to activate becomes inhibited due to pain, swelling and/or trauma [1,2]. This leads to muscle wastage and poorly controlled muscle activation patterns, limiting the individual’s ability to properly recover during the healing process and placing them at an increased risk of future injury . To prevent this, NMES is used to send an electrical current into the muscle to cause it to contract. In doing so, the muscle is being used and thus minimises muscle wastage; whilst also aiding to regain strength and restore correct movement patterns [1,2]. NMES has a wide practical application with research supporting its efficacy in chronic disease management , post ACL repairs  and even in neurological injuries such as stroke . The small battery-operated device is portable and thus can be used on essentially any type of land-based exercise whether that be in laying down or during a functional movement.
TENS is similar to NMES, however where NMES is used for muscle activation, TENS is used for pain management [5,6]. The pulsed currents are sent through the muscle to help stimulate the release of various chemicals . These chemicals help assist in reducing the sensitivity of the muscles and surrounding tissue by inhibiting neural pain pathways to the brain [5,7]. Current research demonstrates proven efficacy for TENS in decreasing pain compared to both placebo and anti-inflammatories . TENS is often used for a multitude of different conditions including arthritis (both osteo and rheumatoid) , neuropathic (nerve related)  and even post- surgical pain . It is a small portable battery-operated device, making it easily portable and usable regardless of whether you are at home, in the clinic or at work.
IFT is a form of TENS where rather than sending one frequency current, it utilises two alternating currents simultaneously . These two currents become superimposed on each other where they intersect, enabling the ability to stimulate deeper within the targerted tissue . This results in a reduction in pain in a similar underlying mechanism to TENS . Compared to placebo, IFT has been found to have a positive effect on pain reduction . IFT also can have positive effects on improving circulation and decreasing oedema by assisting in the removal of fluid in both the circulatory and lymph systems . Unfortunately, unlike NMES and TENS, IFT is a larger stationary device and thus does not provide the portable convenience like the others.
Take home message
There is a variety of different e-stim devices all used for different purposes. Current research supports their use as an adjunct to therapy, meaning they aren’t a complete cure within themselves . The use of e-stim is relatively safe with the most common side effects reported including pain, discomfort and skin irritation . Several contraindications and precautions do come with the use of these devices , but your physio will assess you to clear these risks before starting the treatment to ensure your safety.
If you have any questions regarding e-stim or think you may benefit from its application, please give us a call at (02) 8411 2050. At Thornleigh Performance Physiotherapy, we can give you an accurate diagnosis and treatment, to help you get back in action as soon as possible. We are conveniently located near Beecroft, Cherrybrook, Hornsby, Normanhurst, Pennant Hills, Waitara, Wahroonga, Westleigh, West Pennant Hills, and West Pymble.
Brukner P. Brukner and Kahn’s Clinical Sports Medicine. 4th Editio. McGraw-Hill Australia; 2012.
Kim K-M, Croy T, Hertel J, Saliba S. Effects of Neuromuscular Electrical Stimulation After Anterior Cruciate Ligament Reconstruction on Quadriceps Strength, Function, and Patient-Oriented Outcomes: A Systematic Review. J Orthop Sport Phys Ther. 2010;40(7):383-391. doi:10.2519/jospt.2010.3184
Jones S, Man WD-C, Gao W, Higginson IJ, Wilcock A, Maddocks M. Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease. Cochrane Database Syst Rev. 2016;(10). doi:10.1002/14651858.CD009419.pub3
Pomeroy VM, King LM, Pollock A, Baily-Hallam A, Langhorne P. Electrostimulation for promoting recovery of movement or functional ability after stroke. Cochrane Database Syst Rev. 2006;(2). doi:10.1002/14651858.CD003241.pub2
Sluka KA (Kathleen A, International Association for the Study of Pain. Mechanisms and Management of Pain for the Physical Therapist. https://books.google.com.au/books?hl=en&lr=&id=ng2DCwAAQBAJ&oi=fnd&pg=PT22&dq=Mechanisms+and+management+of+Pain+for+Physical+therapists+&ots=QW8vap0AOC&sig=7v6EK-jAhIoZbjlXu--KnLykUvs#v=onepage&q=Mechanisms and management of Pain for Physical therapists&f=false. Accessed February 26, 2019.
Gibson W, Wand BM, Meads C, Catley MJ, O’Connell NE. Transcutaneous electrical nerve stimulation (TENS) for chronic pain - an overview of Cochrane Reviews. Cochrane Database Syst Rev. 2019;2:CD011890. doi:10.1002/14651858.CD011890.pub2
Ahmed S, Haddad C, Subramaniam S, Khattab S, Kumbhare D. The Effect of Electric Stimulation Techniques on Pain and Tenderness at the Myofascial Trigger Point: A Systematic Review. Pain Med. January 2019. doi:10.1093/pm/pny278
Gibson W, Wand BM, O’Connell NE. Transcutaneous electrical nerve stimulation (TENS) for neuropathic pain in adults. Cochrane Database Syst Rev. 2017;9:CD011976. doi:10.1002/14651858.CD011976.pub2
Almeida CC de, Silva VZM da, Júnior GC, Liebano RE, Durigan JLQ. Transcutaneous electrical nerve stimulation and interferential current demonstrate similar effects in relieving acute and chronic pain: a systematic review with meta-analysis. Brazilian J Phys Ther. 2018;22(5):347-354. doi:10.1016/j.bjpt.2017.12.005
Samuel SR, Maiya GA. Application of low frequency and medium frequency currents in the management of acute and chronic pain-a narrative review. Indian J Palliat Care. 2015;21(1):116-120. doi:10.4103/0973-1075.150203