The roots of using electrical stimulation for pain control and relief stretch all the way back to ancient Rome. In about 63 AD, Scribonius Largus reported that standing on an electrical fish at the seashore could reduce pain. Between the 16th and 18th centuries, several devices were used to produce electrical signals for the treatment of headaches and other types of pain. Benjamin Franklin was reportedly an advocate of early electrotherapy techniques for pain reduction. Fast forward to today, and electrotherapy equipment and techniques have blossomed into a well-respected and widely used field of medicine used by physiotherapists and sports medicine professionals across the globe, helping to treat sports injuries and other health-related issues. In this post, we set out to briefly explain how this form of therapy works. We will also identify some of the most commonly experienced benefits of electrotherapy.
What Is Electrotherapy?
Electrotherapy is a form of medical treatment that uses small electrical impulses to repair tissue, stimulate muscles and increase sensations and muscle strength. It can assist pain reduction and the natural healing response of the body. Electrotherapy has short-term benefits that can assist with the earlier introduction of other longer lasting techniques such as exercise prescription.
While many patients will feel the immediate benefits of electrotherapy, it is wise to think of these passive modalities as comparable to pain relieving or anti-inflammatory medications. Electrotherapy offers short term pain relief or inflammation reduction and allows you to continue moving and functioning as comfortably as possible until you can address the underlying cause of the pain.
Benefits Of Electrotherapy
Electrotherapy utilizes electrical signals to disrupt the ability of the body to transmit neural pain signals to the brain. It effectively overwhelms the pain signals that the body is sending to the brain using the “gateway” approach to pain mitigation. The gateway approach is used in other forms of therapy such as the application of topical analgesics. However, generally speaking, electrotherapy has proven to be a more useful tool for the application of the gateway theory than many types of conventional medication.
In addition to pain reduction, the electric current can also speed tissue healing in the case of patients with tissue damage.
There are several different forms of electrotherapy. Some of the most commonly used forms include ultrasound, transcutaneous electrical nerve stimulation (TENS), interferential therapy, electrical muscle stimulation and laser therapy.
There are also widely varying benefits of electrotherapy. Ultrasound uses sonic waves to promote healing, while interferential therapy and TENS (discussed below) reduce pain through nerve manipulation. Laser therapy is useful for repairing damaged tissues; this treatment can target the injured tissues with high levels of accuracy but is also extremely intense.
Transcutaneous Electrical Nerve Stimulation (TENS)
TENS is an electrotherapy treatment that is a popular solution for a variety of painful conditions such as arthritis, lower back pain, labour pain and nerve related pain, including phantom pain.
TENS works by using a (usually portable) electrical device to deliver electrical impulses through the skin. The device is connected by wires to electrodes which the physiotherapist places on the skin adjacent to the area of the pain. The device then passes a small, low-intensity electric charge through the area.
Benefits Of TENS
TENS can work in two ways. The first uses high frequency signals to selectively stimulate certain ‘non-pain’ nerve fibres to send signals to the brain that block (“overwhelm”) other nerve signals carrying pain messages.This is the gateway approach to pain reduction discussed earlier.
In addition, TENS uses low frequency signals that stimulate the production of endorphins. Endorphins are natural pain-relieving hormones which act as a built-in pain management system.
There is a tradeoff between high and low frequency stimulation. High frequency stimulation is tolerable for hours, but the resultant pain relief lasts for a shorter period of time. Low frequency stimulation is comparable to acupuncture and is usually tolerable for short periods only. However, the resulting pain relief lasts much longer than that resulting from high frequency stimulation. Low-frequency stimulation, sometimes compared to acupuncture, is more uncomfortable and tolerable for only around 20-30 minutes, but the resultant pain relief lasts longer.
TENS users should try placing the electrodes in various places relative to the painful area. For example, they can place them directly over the area, on an adjacent area or over the nerves serving the area. In some cases, TENS users may even find relief placing them on the side of the body opposite the site of the pain. It is important to try the unit for periods of several days with alternative electrode positions before deciding whether this will be an effective type of treatment. For these reasons, users should consider a home trial that could last for several days to weeks.
Interferential Therapy (IFT) is a deeper, more intensive type of TENS treatment. IFT uses dual high frequency electrical signals that are slightly out of phase and are transmitted into the body simultaneously. The signals are transmitted so their paths will actually interfere with one another (giving the treatment its name). This interference produces a “beat” frequency that simulates the effect of subcutaneous (i.e. under the skin) low frequency stimulation.
IFT is usually administered by a health care practitioner such as a physiotherapist. The therapist places damp sponges on the body and these produce low level signals that simulate a “pins and needles” sensation. The physiotherapist will adjust the treatment to target the correct bodily structures and/or to treat a specific condition or body area.
Benefits Of IFT
There are five main clinical needs for which research has found IFT to be an effective solution. These include pain relief, muscular stimulation (to mitigate muscle wastage, facilitate muscle re-education and to maintain joint range of motion), improved local blood flow, edema reduction and acceleration of soft tissue healing.
For patients experiencing acute conditions, the physiotherapist will usually try shorter treatment times of 5-10 minutes. For other patients, he/she may try stimulating the tissues for longer periods of possibly 20-30 minutes.
In future posts we will go into additional details of the benefits of electrotherapy and how health care professionals can combine it with other types of therapy for optimal results. We will also discuss the benefits of electrotherapy as experienced through other modalities such as laser therapy.