Electrotherapy is the use of electrical current to decrease pain, improve movement, and strengthen muscles. Depending on the type of electric current used, the effect varies. Our Burnaby Physiotherapy may use electrotherapy to:
How does TENS Electrotherapy decrease pain?
1) Stimulating Sensory Nerves
Have you accidentally hit your shin somewhere and found yourself grabbing your leg then vigorously rubbing your shin to get rid of the pain? The effect of electrotherapy on pain relief is similar to this concept.
When you rub your shin, you are stimulating other sensory receptors to override the pain signals that are being sent to the brain from the impact. Using electrotherapy for pain relief works the same – you are using the electric current to stimulate other nerve receptors such as nerves that sense vibration, light touch, and pressure to override the pain signals going to your brain. This causes the brain to perceive more vibration, touch, and pressure sensations rather than the pain from your injury. This is known as the ‘Gating theory’.
2) Release Of Pain-Relieving Chemicals
Electrotherapy allows the body to release more endorphins in the body. Endorphins are naturally made by the body to decrease pain and increase the feeling of well-being.
3) Alter Brain and Spinal Cord Activity
Depending on the type of electrical current used, electrotherapy can alter the types of substances released at the brain and the spinal cord.
If you have chronic pain, you must have heard the term “central sensitization”. This is where your brain chemicals have changed leading to a lower pain threshold (hypersensitivity), and the normally non-painful stimuli can be perceived as painful (allodynia).
Electrotherapy can decrease certain chemicals in the spinal cord (ie. substance P, glutamate) which in effect decreases the pain signals going to the brain.
I Have My Own Tens Electrotherapy Machine. What Parameters Should I Use?
The setting of the TENS machine depends on your injury, your pain, and the goal of your treatment. The two most common settings are the:
1) Conventional TENS therapy (Low intensity, high frequency, short pulse duration)
Use this if you:
Setting: > 100hz, pulse duration 50-80 microseconds
2) Acupuncture-like TENS therapy (high intensity, low frequency, long pulse duration)
Use this if you:
Make sure you see a visible muscle twitch when using this setting, and it should not elicit any pain. One interesting fact about AL-TENS is that it will not work for you if you have built up a tolerance to opioids, so for those who are on medications such as oxycodone, hydrocodone, morphine, and codeine, conventional TENS will be a more effective setting.
With both conventional and AL-TENS, make sure the intensity is strong but comfortable.
Where Do I Place My Electrode Pads?
There are 4 ways to choose where to put your electrode pads from your electrotherapy machine. Certain methods require more anatomical knowledge, which may be better applied by one of our registered Physiotherapists in Burnaby.
1) Painful area- just place the electrode pads right over the painful area. This is best used with conventional TENS. Using AL-TENS at the painful area will likely irritate it.
2) Peripheral nerve- chosen depending on the area and nerve involved
3) Spinal nerve- chosen depending on the dermatome or myotome
4) Other points- such as acupuncture points, nerve points, trigger points
How Can I Maximize The Effects Of My Electrotherapy Treatment?
You can build a tolerance to TENS and other forms of electrotherapy. To prevent tolerance, avoid daily use of the machine with the same parameters (frequency, intensity, pulse duration). If you are using it daily, change the electrotherapy parameters.
Ensure Proper Intensity
To get the best result from your electrotherapy machine, make sure you are always using the strongest intensity that is still comfortable for you. This allows more sensory nerves to be activated.
Proper Electrode Placement
You can choose one of the 4 methods mentioned above for electrode placement, but there is evidence that using acupuncture points is more effective than non-acupuncture points.
INTERFERENTIAL CURRENT (IFC) THERAPY
Another widely used form of electrotherapy is the IFC current. The main difference between IFC and TENS electrotherapy is how deep it travels under the skin, and the comfort level.
IFC electrotherapy is mainly used for:
IFC allows the user to focus the electrotherapy current on specific tissues, and it decreases pain by stimulating the peripheral nerves of the body. It uses two medium frequency electrical currents and crosses them to produce a resultant beat frequency. To the user, it may feel quite similar to a TENS machine. The advantage of IFC electrotherapy is that you can focus the treatment on a deeper structure, stimulate more tissues at once, and can potentially stimulate the healing of tissues.
NEUROMUSCULAR ELECTRICAL STIMULATION (NMES)
The third most common form of electrotherapy is NMES or electrical muscle stimulation. This form of electrotherapy is used for activating, retraining, and strengthening muscles.
Our Burnaby Physiotherapists may choose NMES as the preferred form of electrotherapy if you have difficulty contracting specific muscles, or after surgery, if your muscles have significantly reduced in size. When NMES is used, it feels like your muscles are contracting fast and strong during the work interval, and relaxed during the rest interval.
There are other forms of electrotherapy offered at our Physiotherapy clinic such as microcurrent, and Trabert current. These forms of electrotherapy are less commonly used, but if you are curious about a specific type of electrotherapy not mentioned in this section, feel free to contact us!