When was the last time you checked the state of your mTrigger biofeedback electrodes? With all the commotion of the clinic, little attention is likely paid to the state of electrode pads. Most rehab professionals often just slap the electrodes on and get the patient started exercising. However, not paying attention to the quality of your electrodes and improper electrode care can drastically alter the data and ultimately the outcome of your exercises. Just like you wouldn’t give a patient a resistance band you know is going to break, you don’t want to use electrode pads you know aren’t going to perform well.
mTrigger electrodes are sensing electrodes. Meaning they pick up the electrical signal from the efferent neural axon to the muscle. Therefore, full contact with the skin over the target muscle belly is extremely important.
As rehab professionals, we strive to help patients improve while demonstrating competence, confidence, and knowledge in our practice. When a patient is performing exercises with biofeedback but getting inconsistent and confusing results due to poor electrode adherence, they quickly become confused, and lose confidence in their therapist. When things like this happen, we are quick to blame the technology or some other factor, but the answer could simply be overused electrodes.
Whether due to being in a time crunch, trying to cut costs, or out of laziness, electrodes often get used well past their prime. Aside from the sanitary issues this raises, trying to overuse electrodes doesn’t provide accurate results or look good for the therapist.
Let’s review some of the common issues related to improper electrode usage.
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- Electrodes fall off during the exercise
- Poor adherence to the skin leads to increased feedback and false readings on the monitor
* Notice how during this exercise the sEMG readings don’t really make sense. The goal is very low and still there is very little to no electrical activity. This can happen when there is poor electrode contract with the skin. The opposite can also happen where you get extremely high electrical activity that doesn’t match what you would expect either. See the video below for this example. Notice how throughout the exercise the meter “jumps” all over and appears to be out of sync with the exercise. This is another indication of poor electrode contact with the skin.
- Improper skin care causes too feedback (hair/lotion)
* Notice how in this video, the amount of arm hair significantly interferes with the sEMG signal, leading to false readings.
- Electrodes fall off during the exercise
While best practice is for each patient to get their own set of electrodes, let’s take it one step further and say best practice is to also use electrodes that still have a strong adhesive, maintain full contact with the skin, and are used on skin that has been properly cleaned and prepped. Depending on the frequency of use, this may mean some patients require more than one package of electrodes for their full course of rehab.
To help with increasing the longevity of the sensing electrodes, here are some best practices when it comes to electrode care.
Skin Preparation
EMG signals can be highly variable due to extrinsic factors such as skin preparation and impedance. In order to promote a clear signal, the targeted area should be shaved of excess hair and cleaned with alcohol. The skin should also be free of any dirt, oils, or lotion before the electrodes are placed. This helps maintain the longevity of adhesive, minimizing the breakdown that occurs from skin oils.
Improving Contact
In cases where the electrodes are over a smaller muscle or an area of the body that moves a lot, the electrodes can be gentle secured with something like flex wrap to improve contact. Note that if wrapped too tight, this will interfere with the EMG signal.
Storage
To help maintain the adhesiveness of the electrodes, it is recommended they are stored in a cool, dry place. Furthermore, each package should be labeled with each individual patient’s name.
In the scheme of what rehab professionals do every day, practicing proper electrode care and usage is quite simple. Don’t let overused electrode pads interfere with your quality of care.
Summary
Proper electrode usage with the mTrigger biofeedback device ensures you get the results you want when performing exercises with your patients. Simple steps such as cleaning the skin, not sharing pads between patients, and correct storage are easy ways to achieve favorable results. Make sure you are taking care of your electrodes so you can better take care of your patients.
Adjusting your mTrigger Time Settings
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References
1. Koiler R, Bakhshipour E, Glutting J, Lalime A, Kofa D, Getchell N. Repurposing an EMG Biofeedback Device for Gait Rehabilitation: Development, Validity and Reliability. International Journal of Environmental Research and Public Health 2021, Vol 18, Page 6460. 2021;18(12):6460. doi:10.3390/IJERPH18126460
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