Por this reason, we interviewed Diego Rodríguez Mena, a neurophysiologist and secretary of the Spanish Society of Clinical Neurophysiology (SENFC), at Europa Press Infosalus. He explains that this technique is used to detect and analyze the electrical signal generated when a muscle contracts, in order to evaluate the muscular function and communication between nerves and muscles.
«The electromyographic signal allows the construction of the electromyogram, which corresponds to the temporal and spatial sum of the action potentials of motor units (PUMs) during contraction, allowing for a precise and objective quantification of muscle bioelectric behavior,» he adds.
ELECTRODES ARE INSERTED INTO VARIOUS MUSCLES
Therefore, this specialist explains that electromyography involves the direct recording of muscle activity, both at rest and during contraction, by inserting a needle electrode into various muscles: «A pinching sensation is felt when the needle is inserted, and sometimes a dull pain while the needle is in place. Electrical currents are not usually applied. The needles capture the electrical activity generated by the muscle. This activity appears on a screen and is reproduced through a speaker, allowing the doctor to see and hear it.»
As indicated, most patients describe EMG as ‘an uncomfortable procedure rather than painful’, as the insertion of needle electrodes can cause a pinching or tingling sensation; although the SENFC secretary insists that it is usually brief. «The discomfort varies depending on the patient’s sensitivity and the location of the muscle being evaluated,» he concludes.
During the test, this spokesperson for neurophysiologists maintains that it is important for patients to feel comfortable, communicating any concerns or questions they may have before and after the test; as this can help reduce anxiety and improve the overall experience.
WHEN IS IT INDICATED
Diego Rodríguez Mena emphasizes that electromyography is a valuable technique in the diagnosis of many neuromuscular diseases, as well as disorders related to the peripheral nervous system, as it allows for the evaluation of muscle and nerve electrical activity, which can help identify muscle damage or dysfunction, as well as nerve dysfunction.
«I would recommend an EMG when there is suspicion of neuromuscular disorders, or when other studies have not provided a clear diagnosis. EMG is particularly useful for evaluating muscle function and communication between nerves and muscles, which may not be evident in other tests,» this expert insists.
PREPARING FOR THE TEST
The duration of an EMG may vary, according to Rodríguez Mena, but generally takes about half an hour to an hour. «During the test, the patient may be asked to perform specific movements or to contract muscles for a more comprehensive evaluation. It is important for the patient to follow the technician’s instructions to obtain accurate results,» he adds.
According to the SENFC secretary, prior body hygiene is essential, and patients should not use lotions, oils, or moisturizing creams. «Fasting is not necessary, and no additional preparation is needed,» he emphasizes.
In fact, this expert indicates that the patient can take their regular medication; he also warns that before starting the study, the skin temperature will be checked, and if it is below the correct temperature, the area to be studied will be warmed to avoid errors in interpreting the findings. «It is also important to inform the doctor about any medication being taken, especially anticoagulants, and any relevant medical conditions,» he concludes.