EMG (Electromyography)

In order to diagnosis your condition, the physician will gather patient history information and perform a physical exam. X-rays reveal bones in the body, but not soft tissues like spinal discs. An MRI, conversely, can show soft tissue and if you have a herniated disc. Your physician may also order an EMG diagnostic test to record and analyze electrical impulses between muscles and nerves. These tests are used to diagnose, evaluate and treat neuromuscular, musculoskeletal, and nervous system disorders. EMG testing can provide your doctor with specific information about the extent of nerve and/or muscle injury. EMG testing can also determine the exact location of injury and give some indication whether the damage is reversible.

Why is an EMG test ordered?

An EMG diagnostic test may be ordered for patients who experience numbness, tingling, pain, weakness, or muscle cramping. Nerve conduction studies and EMGs are types of tests that the spine physician may use to diagnose symptoms. Conditions that EMG testing helps diagnose include a pinched nerve, radiculopathy, sciatica, muscle diseases, muscular dystrophy and many others.

How does an EMG test work?

Nerve conduction studies produce signals that travel down nerves and that are recorded by electrodes placed on the skin. An EMG is performed by placing a small, acupuncture-sized needle into several muscles. By gently moving the needle, electrical activity in the muscle is detected, and this information is relayed to the machine, which produces sound and wave patterns which are interpreted by the physician. Both nerve conduction studies and EMGs can help physicians determine the causes of a patient’s back or neck problems and the appropriate treatment options.

What happens if I don’t want to have an EMG?

The key benefit of an EMG diagnostic test is that the spine surgeon is trying to determine exactly what is the pain symptom generator and if there is damage done to the nerves that radiate into the arm and hand, and leg and foot. The diagnostic information from an EMG test can play an important role in deciding:

  1. IF you need surgery, and
  2. What level in your back or neck is likely causing your pain symptoms, numbness or weakness.

An EMG, along with an MRI, provides the spine surgeon key information to increase the likelihood that a spine surgery will be successful in relieving your symptoms.

Who performs the needle electromyogram (EMG) and nerve conduction study?

An EMG diagnostic test is performed by an MD or DO physician who has completed 4 years of medical school followed by residency program training of 3 or 4 more years. EMGs are typically performed by physiatrists or neurologists with advanced training and experience in these tests.

How do I prepare for an EMG?

Because oily skin may affect the outcome of the tests, you should shower the morning of your injection, and do not apply cream or lotion to the skin. Be sure to inform the doctor if you are taking any blood-thinners or aspirin medications or if you have a pacemaker. EMGs typically involve only mild discomfort and there are few serious risks. These include slight bruising, bleeding or soreness in areas where the electrodes or needles are placed. As with any injection into the skin, there is also a slight risk of infection.

What will a Nerve Conduction Study reveal?

Nerve conduction studies can show your spine specialist how well the body’s electrical signals are traveling to a nerve. During this test, small electrical shocks are applied to the nerve in order to record how the nerve works. The shocks may cause a quick, mild and tingling feeling. The doctor may test several nerves.

My doctor ordered an EMG. What does this involve?

During an EMG, a small, acupuncture size needle is placed in several muscles to help diagnosis a back or neck condition. There may be a bit of discomfort when the needle is inserted. The physiatrist will only test the muscles necessary for diagnosis. Physicians are able to see and hear the electrical signals that travel from the needle to the EMG machine.

How long will an EMG / Nerve Conduction Study take?

EMG testing usually takes anywhere from 30 to 90 minutes, depending on the condition being tested and findings of the study. Patients can do normal activities, like eating, driving, and exercising, before and after the tests.

What is Neuromuscular Medicine?

Medical care for patients with disorders of the peripheral nervous system (PNS) and its relationship with the central nervous system is known as Neuromuscular medicine. The peripheral nervous system involves the motor and sensory neurons, peripheral nerves, neuromuscular junctions, and muscles. A subset of neuromuscular medicine is electrodiagnostic medicine.


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