Electromyography (EMG) is the process of measuring the response of muscles to electrical signals sent by nerves. This test is used to help detect abnormalities of the neuromuscular (muscle and nerve structure) system. During an EMG, one or more thin needle electrodes are inserted into muscle tissue. The electrical activity collected by the electrodes is then visualized on an oscilloscope screen. Normally, muscles do not produce electrical signals when they are at rest, but when the electrode is inserted, activity can be observed for a short period of time. The electrical activity during resting, mildly contracting and strongly contracting states of the muscles is measured and evaluated.
The patient may also be asked to move their muscles in certain ways during the EMG test. This is done to observe and evaluate how the muscles respond. In addition to EMG, a nerve conduction study (NCS) may also be performed. NCS measures the speed and amount at which nerves transmit electrical impulses. Using a combination of EMG and NCS, the presence, location and extent of nerve and muscle damage can be determined. These procedures play an important role in the diagnosis and treatment of many nerve and muscle diseases.
Advantages of EMG (Electromyography) performed by a Neurologist
For precise signal monitoring and testing, the quality of the EMG device and electrical noise separation and filtering software are of utmost importance. Our hospital uses world-leading and high-tech EMG devices.
However, these tests are usually performed by technicians and interpreted by specialized physicians. This can cause some diagnoses to be missed. For this reason, in our hospital, EMG tests are performed only by a "Neurology Specialist", which is rarely seen in our country.
Which diseases is EMG (Electromyography) performed to diagnose?
EMG test is applied for the diagnosis of diseases occurring in the muscle and nerve structure. The functionality of the muscles and nerve structure is determined through EMG testing. The most common of these diseases are muscle-nerve diseases, ALS, spinal cord diseases, focal neuropathies.
The EMG test is mostly used to diagnose the following diseases:
Focal Neuropathies
EMG (electromyography) is often used to diagnose problems that cause damage to a single nerve. Common examples are carpal tunnel syndrome in the wrist and cubital tunnel syndrome in the elbow.
In addition, EMG is used in peroneal nerve neuropathy in the leg or tarsal tunnel syndrome in the ankle. In clinical experience, sciatic nerve damage can be seen in incorrect injection from the hip or hip dislocations. In such cases, EMG test is preferred to make the correct diagnosis. In addition, this method also provides information about the severity of nerve damage and future recovery in facial paralysis.
Diabetes and Kidney Failure
EMG is used for diagnostic purposes in widespread damage to peripheral nerves due to diabetes, kidney failure and some genetic causes that impair the function of nerves.
Damage to Nerve Roots due to Lumbar and Cervical Hernia
It is also used to identify diseases that cause damage to the nerve roots leading to a herniated disc or cervical disc of spinal cord origin.
Myopathies
EMG testing is an effective method for diagnosing diseases that cause damage and wasting of muscle fibers.
Polio or ALS
EMG is also used to diagnose diseases that cause damage to motor nerve cells in the spinal cord, such as polio or ALS.
Neuromuscular Diseases
EMG is an important test used to identify diseases such as myasthenia gravis, in which the electrical conduction between nerves and muscles is impaired.
Althoughthe EMG procedure varies depending on the patient's condition and the preferences of the practicing physician, the general steps are as follows:
Pre-Procedure Preparations:
- Your doctor will explain the details of the procedure and give you the opportunity to answer your questions.
- In most cases, you do not need to follow a special diet before the test.
- All medications and supplements should be reported to the doctor.
- Avoid applying lotions or oils on the skin on the day of the procedure.
- If you have a pacemaker, this should be reported to your doctor.
Procedure Sequence:
- The procedure is led by a neurologist. During the test, thin, sterile needles are inserted into the muscle. These needles measure electrical activity and display it on an oscilloscope.
- The insertion of the needles is usually painless, but a slight pain may be felt.
- The patient is asked to make various movements by contracting the muscles. This provides information about how well the nerves stimulate the muscles and how the muscles respond to these stimuli.
Post Procedure Instructions:
- You may experience mild muscle soreness after the procedure. If any excessive pain, swelling or pus is noticed, a doctor should be consulted.
"NCS" Procedure
NCS (Neural Conduction Studies) is a test that measures how quickly and efficiently electrical impulses are transmitted along a nerve. This procedure is often performed in conjunction with EMG testing, and together both procedures help to identify conditions such as nerve damage and muscle diseases.
Before the Procedure:
- NCS usually does not require any special preparation.
- Just as with the EMG, all medications should be reported to the doctor and the skin should be left clean on the day of the procedure.
During the Procedure:
- During NCS, mild electric shocks are delivered through electrodes placed on specific nerves. This measures the nerve's response to electrical impulses.
- Mild discomfort may be felt during the test, but it is usually brief and mild.
After the Procedure:
- After the test, the paste used to attach the electrodes is cleaned and patients can usually return to their normal activities.
- Both tests are important tools for assessing nerve and muscle health and are used to diagnose many neuromuscular disorders.
