What is electromyography?
Electromyography (EMG) is a diagnostic procedure that evaluates the health condition of muscles and their controlling nerve cells. These neurons are referred to as motor neurons. They transmit electrical signals that contract and relax muscles. The EMG converts these signals into graphs or statistics, aiding diagnosis.
A doctor will usually prescribe an EMG when someone shows muscle or nerve disorder symptoms. Among these symptoms may be tingling, paralysis, or unexplained limb weakness. EMG results can aid in diagnosing muscle disorders, nerve disorders, and disorders influencing the nerve-muscle connection.
Why is electromyography performed?
If you are experiencing symptoms that may indicate a muscle or nerve disorder, your doctor may perform an EMG. Among the signs that may necessitate an EMG:
- a tingling sensation
- lack of sensation
- muscle weakness
- muscle pain or cramps
- a state of paralysis
- involuntary muscle twitches.
The results of an EMG can assist your physician in determining the underlying cause of your symptoms. Possible reasons may include:
- musculoskeletal conditions, such as muscular dystrophy
- Myasthenia gravis is a disorder that affects the ability of the motor neuron to transmit electrical signals to the muscle.
- Peripheral nerve disorders, such as carpal tunnel syndrome, affect nerves outside the spinal cord.
- Neurological disorders, such as amyotrophic lateral sclerosis (ALS).
How should I prepare for an electromyogram?
Inform your physician of any over-the-counter and prescription medications you may be taking. It is also essential to inform your doctor if you have a bleeding disorder, a pacemaker, or an implanted defibrillator. If you have any of these medical conditions or devices, you may not be able to have an EMG.
If you can undergo an EMG, you should take the following precautions beforehand:
- Do not smoke at least three hours before the procedure.
- Take a shower to remove any oils from your epidermis. Do not apply lotions or cosmetics following cleansing.
- Put on comfortable apparel that does not obstruct the area that your doctor will evaluate. You may be required to change into a hospital garment immediately before the procedure.
What occurs throughout electromyography?
You will be instructed to lie on an examination table or recline in a chair. Your physician may advise you to assume various positions during the procedure.
An EMG examination consists of the nerve conduction study and needle EMG. The nerve conduction examination is the initial step in the process. It involves placing small sensors called surface electrodes on the skin to assess the ability of the motor neurons to transmit electrical signals. The second portion of the EMG procedure, needle EMG, also evaluates electrical signals using sensors. These sensors are referred to as needle electrodes, and they are inserted directly into muscle tissue to assess muscle activity at rest and during contraction.
The nerve conduction examination is carried out initially. During this portion of the procedure, your physician will apply multiple electrodes to the surface of your skin, typically in the affected area. These electrodes will evaluate the communication between your motor neurons and muscles. Upon completion of the examination, the electrodes are removed from the epidermis.
Following the nerve conduction study, your physician will execute the needle EMG. Your physician will first apply an antiseptic to the affected area. Then, they will insert electrodes into your muscle tissue using a catheter. You may experience minor discomfort or pain as the needle is inserted.
The needle electrodes will assess the electrical activity of your contracting and at-rest muscles. These electrodes will be removed once the examination is complete.
Throughout both phases of the EMG procedure, the electrodes will transmit minute electrical signals to the nerves. A computer will convert these signals into graphs or numerical values that your physician can interpret. The duration of the total process should be between 30 and 60 minutes.
What risks are associated with electromyography?
An EMG is a low-risk examination. However, you may experience discomfort in the tested area. The discomfort may last a few days and can be alleviated with an over-the-counter pain reliever such as ibuprofen.
Rarely, you may experience tingling, bruising, and oedema at the needle insertion sites. Inform your physician immediately if the swelling or discomfort worsens.