Electromyography (EMG) – Purpose & Procedure

What is an EMG (Electromyography) test?

EMG (Electromyography) is a diagnostic test mainly done to check the muscle’s health. At the same time, muscle contraction or relaxation is a response to the nerve’s stimulation of the muscle. EMG can be prescribed to detect neuromuscular abnormalities. EMG measures the electrical signals produced by the muscle during forceful contraction, slight contraction, and rest. Your healthcare provider or your doctor can ask you to take EMG if you have symptoms like muscle soreness, tingling or numbness. 

During EMG test, one or more needles are inserted through the skin into the muscles, these small needles are also called electrodes. These electrodes then detect the electrical activities and display them on an oscilloscope (Is a monitor that used to display electrical activity in the form of waves to make them understand). Whereas, an audio-amplifier is also used to hear the electrical activity of muscles. 

Every movement you do, like moving your leg to nod your head, involves complex communication between the central nervous system (your brain and spinal cord), nerves, and muscles. When you move your motor nerve send electrical signals to your muscles and those muscles are detect by the EMG during the test. If there is any issue with the motor nerve, muscle or the communication between the two will be detected by the EMG and the result will be printed out. 

Why is EMG performed?

Mainly, EMG is suggested to a person who has signs or symptoms that may indicate nerve muscle or nerve disorder. Symptoms may include:

• Numbness
• Tingling
• Muscle cramp or pain
• Muscle weakness
• Certain types of limb pain

Whereas an EMG can detect several diseases or injuries that affect your motor nerve and muscle. The result of EMG can help the healthcare provider or the doctor to know the real reason for these symptoms. 

• Problem that affects the nerve root that exits to your spin cord, such as pinched nerves, cervical (neck) radiculopathy or sciatica.
• Muscle disorder such as polymyositis or muscular dystrophy.
• Diseases that affect the connection between muscle and nerve, such as myasthenia gravis. 
• Disorder of the spinal cord (peripheral nerves)
• Disorder that affects the motor nerve in the spinal cord or brain. 
• Disorder that affects nerve roots, like herniated disk in the spin. 

How to prepare for an EMG?

For EMG (Electromyography) test you don’t need fasting or any major preparation but when you schedule your EMG you can ask if you need to stop any over-the-counter medication, or any other specific medication needed to be stop before the examination. In some cases, caffeinated beverages such as tea, coffee and cola may be restricted before the test.  

It’s important to bathe or take a shower shortly before the examination to remove any kind of oil from your skin. Make sure not to apply any kind of lotion or cream before the EMG test. Wear comfortable cloths that allow the access to the area to be tested. 

As you go for the EMG test, make sure to notify your doctor if you have a pacemaker or any other electrical medical device, and provide information about your medication and supplements if you are taking any. You should always inform your doctor or the EMG technician if you have any specific medical condition.  

What to do during the EMG test?

An EMG procedure may require you to stay in the hospital if needed. At the same time, the procedure may depend on your health condition and your doctor’s practice. Mostly, EMG is performed by neurologists as they specialise in nerve and brain disorders. In some cases, technologists can also perform some portion of the test. EMG test is mainly performed immediately after nerve conduction, Whereas it is a test that measures the flow of current in nerves before reaching muscles rather than the response made by muscles.

A simple EMG procedure follows these processes:

• First of all, you will be asked to remove any clothing that may cover the testing part; if you are asked to remove clothing, then you will be given a gown to cover. 
• Then, you will be asked to remove jewellery, eyeglasses, hairpins, hearing aids, or any other metal-like object that may interfere with the test or the result. 
• Next, you will be asked to lie down or sit. 
• Then, the neurologist will check and locate the muscles to be studied.
• Then your skin will be cleaned with an antiseptic solution. 
• Next, a fine, sterile needle will be inserted through the skin into your muscle. A ground electrode will be positioned under your leg or arm. 
• There will be five or more needles for the test, as the needle insertion is important. You may feel little pain during the insertion of the electrode. Usually, the process is painless. 
• If you feel pain during the test, you must tell the examiner, as it can interfere with the results. 
• Then, the result of electrical activity from your working muscle will be measured and displayed on the screen.

They may use an audio amplifier to check the sound of the electrical potentials to get better results. If the recorder is attached to an audio amplifier, you may hear the sound of muscle contraction. 

Results of EMG (Electromyography) test

The neurologist will analyse the result of your test and prepare a report. That report will then be checked by your primary care doctor, who orders the EMG and will discuss the report with you to make you understand the situation. Some basic results can be found are:-

• The result will be given to you right after the test.
• EMG shows the electrical activity in the resting muscles.
• It can help to detect muscle disorders.
• Disorders that involve the nerve that connects to the muscle. 
• It can detect inflammation caused by an injury.
• Electromyography tests can reveal abnormal electrical activity that happens when muscles contract or show if a person has a herniated disc or a nerve disorder. 
• Basically, depending on the result, the doctor will suggest the right treatment options for you. 

Conclusion

EMG (Electromyography) test is an easy process; it is mainly used to evaluate the health of muscles and nerve cells that regulate them. EMG is mainly prescribed by doctor to people with symptoms like muscle weakness, tingling and numbness. It also helps to detect muscle or nerve disorder.

EMG test records electrical activity done by muscle during contraction. EMG test includes insertion of needles through skin into the muscles to check there electrical activity while muscle contract. It may be little painful but the pain will be bearable. 

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