Transcutaneous Electrical Nerve Stimulation (TENS) and Neuromuscular Electrical Stimulation (NMES) are forms of electrotherapy. Many people use TENS and NMES units during physical therapy to help with various conditions. However, some have gotten confused between these two devices. TENS units relieve pain. Meanwhile, NMES units help with muscle re-education. To use them, people place electrode pads on specific areas and adjust the output settings. Then, TENS will stimulate the body to alleviate pain, while NMES will cause involuntary muscle contractions.
TENS and NMES therapy have grown in popularity for their non-invasive and drug-free methods of helping patients. However, it is crucial to consult a healthcare professional before using any electrotherapy devices. This ensures safety and compatibility with the device. Moreover, professionals may advise on how to use the machine. This article will present the difference between NMES and TENS machines, how they work, and how to operate them.
What is the Difference Between TENS and NMES Units
Many people use TENS and NMES units in the field of physical therapy. These are both medical electronic devices, but they serve different purposes. TENS primarily provides temporary relief from pain. It works on many acute and chronic pain conditions. A TENS machine generally has electrodes, lead cables, and a controller. However, there are also wireless TENS that use Bluetooth to remove the need for cables.
On the other hand, NMES units include electrode pads, an output controller, lead cables, and a pulse generator. The pulse generator creates the electrical pulses which travel through wires into the body. Typically, TENS machines have a built-in pulse generator, removing the need for an additional device. This makes many TENS units more portable and compact than NMES units.
Furthermore, TENS and NMES machines differ in cost. NMES devices tend to be more expensive than TENS. Their price range lies between $200 to more than $1000. In comparison, TENS machines range from $50 to around $300. This is because NMES machines have more complex systems. Thus, it is crucial to understand which device better suits the condition.
Conditions that Can Benefit from the Devices
These are conditions that can benefit from TENS:
- Fibromylagia: causes widespread musculoskeletal pain, general fatigue, and stiffness.
- Arthritis: a condition born from inflammation of one or more joints.
- Sciatica: caused by injury or pressure to the sciatic nerve. Those with sciatica feel pain in the lower back, which may radiate to the leg.
These are the conditions that NMES helps with:
- Dysphagia: a medical condition wherein people have difficulty swallowing liquids and foods.
- Spastic cerebral palsy: causes muscle stiffness in the legs that makes it difficult for people to walk
- Spinal cord injuries: these can drastically affect mobility.
How TENS and NMES Units Work to Provide Relief
TENS and NMES units both use electrical stimulation to treat their users. Both machines allow users to adjust the device settings for their needs. However, the power and settings used are quite different. TENS machines use electric stimulation to trigger the body to relieve pain. High-frequency stimulation induces the spinal nerve cells to block pain signals from reaching the brain. It also helps increase blood circulation to the area and relieve muscle tension.
Low-frequency stimulation triggers the production of endorphins. This painkilling hormone builds and reduces pain in the area. Endorphins also aid in reducing inflammation and improve moods. To an extent, it can help increase mobility and encourage the person to engage in more activities.
Generally, NMES machines use higher settings than TENS. This allows the electric currents to reach the muscles and cause involuntary muscle contractions. They may also stimulate motor nerves for muscle re-education. NMES units reduce muscle atrophy and increase muscle strength. This is particularly helpful for people undergoing rehabilitation.
Advantages Over Other Relief Methods
TENS and NMES are both non-invasive forms of electrotherapy. This is ideal compared to invasive techniques because there is no risk of infections and complications. Furthermore, these are drug-free and non-addictive. In particular, TENS helps many people reduce or replace their intake of pain medicines. This lessens their risks of experiencing potential adverse effects from medicine, like stomach bleeding, nausea, and kidney diseases.
Furthermore, people may use these electrotherapy devices from the comfort of their homes. This removes the hassle of going to hospitals or therapy clinics. A TENS or NMES session also does not require medical supervision.
How to Operate TENS and NMES Units
TENS and NMES units are straightforward to use. However, consulting a healthcare professional is recommended before using any electrotherapy device. They may ensure the machines are safe for the person to use. In addition, they may advise on how to use the machine for the condition. Moreover, users may read the instruction manual provided by the device manufacturer.
Proper electrode placement is crucial for treatment. But before that, the device user must clean their skin with soap and water. This helps to maintain hygiene and allows the electrode pads to stick better. After attaching the pads, the user may turn the machine on. It is ideal to start on low settings to avoid sudden shock or discomfort. Afterwards, they may increase the settings to their preferred levels.
Generally, TENS sessions last between 20 to 30 minutes. Meanwhile, NMES sessions may take between 45 to 60 minutes. This varies from person to person. However, it is crucial to refrain from overusing these machines to avoid adverse effects, such as skin irritation, mild burns, and muscle damage. After the treatment time elapses, they may turn the machine off and remove the electrodes.
Placement Guide for Electrodes for Effective Use
To ensure the effective delivery of the electrical currents, people must place the electrode pads in the correct areas. For TENS, these are muscle areas near or on the origin of the pain. Meanwhile, users place NMES pads on targeted muscle groups. People may refer to pad placement charts or guides for more specific examples.
It is crucial to avoid sensitive areas when placing electrodes. This includes the spinal cord, throat, chest, eyes, and joints. People must also avoid areas with irritated, infected, or broken skin. This is because electric stimulation may worsen the condition.
TENS and NMES units are helpful for those seeking non-invasive and drug-free methods of relieving pain and increasing muscle strength, respectively. However, it is essential to avoid confusing the two electrotherapy devices. Otherwise, it may result in adverse effects due to misuse. TENS machines relieve pain using high and low frequencies. These trigger endorphin release and blocking of pain signals. Meanwhile, NMES machines induce muscle contractions to maintain or re-establish muscle function.
TENS machines help with conditions like fibromyalgia, sciatica, and arthritis. Meanwhile, NMES units aid those with spinal cord injuries, dysphagia, and spastic cerebral palsy. Generally, TENS units are more compact and portable compared to NMES. One reason for this is that NMES has a separate pulse generator. However, using TENS and NMES are quite similar. Users place the electrodes in their target areas and adjust the settings to their comfort.