Electromyography(EMG)

Overview

Electromyography is a form of electrodiagnostic testing that evaluates the health and function of the skeletal muscles. Aster provides the best services that can evaluate the health of the muscle. It is equipped with the latest equipment for evaluation. Electromyography is one of the most important investigations that not only evaluates the function of the muscles but also evaluates the nerves that control them. Every body movement, from lifting legs to nodding the head, involves complex communication between the central nervous system, nerves, and muscles. Motor nerves send electrical signals to the muscles to move. An electromyogram helps to detect issues with the motor nerves, muscles, or communication between the two.

Electromyography is usually done along with nerve conduction study. The nerve conduction study measures the flow of electrical current through the nerve before it reaches the muscles. EMG measures the response of the muscle to electrical activity. It also measures how much electrical activity a muscle contraction produces.

An electromyography helps to diagnose several injuries or diseases that affect the motor nerves and muscles. It can also help to accurately determine the presence, location, and extent of the injuries and diseases.

The various conditions that electromyography can diagnose are:

• Disorders related to the peripheral nerves, such as peripheral neuropathy. It also diagnoses nerve compression syndromes such as carpal tunnel syndrome.

• Disorders that affect the nerve roots when exiting the spine, such as pinched nerves, cervical radiculopathy, and sciatica.

• Muscle disorders such as muscular dystrophy, polymyositis, and dermatomyositis.

• Conditions that affect the motor neurons in the brain and spinal cord, such as amyotrophic lateral sclerosis.

• Conditions that affect the connection between nerve and muscle, such as myasthenia gravis.

To know the functioning of the EMG, one must understand how the muscle works. The motor nerves send electrical signals to the muscles to tell them what to do. These signals usually originate from the brain and travel down the cord, through the motor nerves, and to the muscles. This electrical stimulation produces electrical activity in the muscle, leading to contraction. The contraction of the muscle produces electrical activity.

At rest, the muscle does not produce any electrical activity. A slight contraction of the muscle produces some electrical activity. The intensity of electrical activity increases as the strength of contraction increases.

In electromyography, the healthcare expert inserts a small needle with electrodes into the muscle to record the electrical activity. However, electrical stimulation is not delivered through the needle. The electrodes record the electrical activity that is produced by the muscles. The needle electrode records the electrical activity when the muscle is at rest and contracting. The needle is then attached to the computer through a cable to see what the muscle is doing at rest and with the movement. An audio amplifier is used to hear the pulses of electrical activity.

The healthcare provider then analyses the recordings to look for any abnormality. This can be interpreted by observing the abnormal recordings obtained when the muscle is contracting and resting.

Before undergoing an EMG test, one must take precautions to prepare for the test.

• One should avoid putting cream, lotion, or perfume on the skin. Cream and lotions can affect the accuracy of the test.

• One must inform the healthcare provider if one takes any anticoagulant, such as warfarin. After the EMG test is done, blood thinners can increase the risk of bleeding.

• One must inform the healthcare provider if one has a pacemaker or any electrical medical device implanted in the body.

• Smoking or drinking caffeinated drinks can interfere with the test.

EMG is usually done after a nerve conduction study has been done. The healthcare provider puts electrodes on the skin's surface during a nerve conduction study. A small electrical impulse is delivered through the electrode, and the response is recorded. Different nerves are tested in this procedure.

The following steps are followed during an EMG:

• One is expected to sit or lie down for the test.

• The provider locates the muscle that they want to test.

• A small needle with an electrode is inserted through the skin into the muscle. These needles usually stay in the muscles. It usually takes 1-2 minutes to examine each muscle.

• One is asked to relax and use the muscles in specific ways, such as lifting or flexing one of the limbs. A machine usually measures or displays the electrical activity of the muscle.

• After the recording is over, the healthcare provider removes the needle and places it on another muscle.

Some soreness in the muscles may persist after the test is done. One must consult a doctor if one experiences pain, local tenderness, swelling, or pus at the needle insertion site. Electromyography is a less risky procedure. The needle insertion site has a small risk of bleeding, infection, and nerve injury. When the muscles along the chest are examined, there is a slight chance that air may leak into the area between the lungs and the chest wall. This can cause the lungs to collapse.

Health Conditions Treated

• Peripheral neuropathy

• Carpal Tunnel Syndrome

• Cervical radiculopathy

• Sciatica

• Muscular Dystrophy

• Polymyositis

• Dermatomyositis

• Amyotrophic Lateral Sclerosis

• Myasthenia gravis