Electromyography Laboratory

Electromyography (EMG) and Nerve Conduction Study (NCS) is the electrical testing of nerves and muscles. First, we review your medical history and perform a neurological examination. Second, we will perform the EMG/NCS study which consists of two parts:

1. First part is the NCS, this involves brief electrical stimulations delivered over the skin to the nerves usually in the arm and/or leg to determine how well your nerves are conducting the electrical signals. This may be performed by a specially trained Nerve Conduction Technologist or a Specialized Neurologist.

2. Second part is the assessment of the muscle activity with an electromyogram (EMG), which requires the insertion of a fine needle into selected muscles to see if there are signs resulting from a nerve damage or if the disease involves the muscles themselves. Typically, during the needle exam, no electrical shocks are delivered. This will be performed by a Specialized Neurologist. 

Both tests may result in some discomfort but are usually well tolerated. The entire test takes approximately 1 hour. Following the testing, the data acquired will be analyzed and a written report will be prepared in the Electronic Medical Record (EMR) and available for your doctor for review. The results of these tests help your doctor determine the cause of your symptoms and select the best treatment for you.

Do not apply any creams, lotions and/or oils on the arms, hands, legs or feet. A shower before the test helps remove natural skin oil, this will reduce the interference with the application of the electrodes. You may be asked to change into a hospital gown and remove jewelry worn on the wrist or fingers.

Please advise the lab staff if you are taking anticoagulants (blood thinning medication such as Coumadin, Xarelto or Eliquis) or if you have any type of blood disorder which may cause excessive bleeding such as hemophilia.

If you are under treatment for Myasthenia Gravis, such as Mestinon, with the authorization of your doctor, please hold off the medication 48 hours prior to your appointment.

Single Fiber Electromyography is a sensitive test in the assessment of the neuromuscular transmission (the connection between the muscle and nerve) when repetitive nerve stimulation is normal.

Before the Single Fiber EMG test:

If you are taking medication such as Mestinon, with the authorization of your doctor, please hold off the medication 48 hours prior to your appointment.

During the Single Fiber EMG test:

The test will take approximately 2 hours and will be performed by a Neurophysiologist.

• First, we review your medical history and perform a neurological examination.
• During the test you will be asked to lie down and relax, and a very fine needle electrode will be placed into one of your muscles which then samples the electrical potentials coming from the muscle while you maintain a low level of activation. The needle electrode will stay in place throughout the test, to record activity from the muscle.
• Though you will feel the needle, it is unlikely to cause you too much discomfort.
• Following the testing, the data acquired will be analyzed and a written report will be prepared and sent to your referring physician. The results of these tests help your doctor determine the cause of your symptoms and select the best treatment for you.

Repetitive Nerve Stimulation is the electrical testing of the neuromuscular junction which is responsible for the chemical transmission of the electrical impulse from a nerve to the muscle. This test may be combined with the routine nerve conduction study (NCS) and is similar to it but does require repetitive stimulation to several nerves. This study is useful in diagnosis of muscle weakness due to disorders of the neuromuscular junction (eg. Myasthenia Gravis, Lambert Eaton myasthenic syndrome).

SUDOSCAN evaluates sudomotor function on the palms of the hands and soles of the feet. It uses a very low DC voltage (<4V) to activate the sweat glands and measures the current of chloride ions that flow out of the sweat glands in response to the electrical impulse. The test is painless, very quick (about 3 minutes), and easy to perform.

How is it performed?

You will be asked to take your shoes and socks off; then you will stand still with your hands and feet on the sensor plates. If you are unable to stand still for 3 minutes on the plates, you may be asked to sit for the test.

What information does SUDOSCAN provide?

Testing the function of sweat glands, which are innervated by the autonomic system, may help your referring physician utilize this information to complement findings from their examination when Peripheral Autonomic or Small Fiber Neuropathy is suspected. The test results are readily available within minutes and will be sent to your referring physician.

What is a Sudoscan? 

In addition to nerve conduction and EMG testing, patients referred for evaluation of neuromuscular symptoms may undergo nerve or muscle ultrasound. This is a painless, noninvasive procedure that is used in conjunction with standard electrodiagnostic studies. High resolution ultrasound allows visualization of affected nerves and muscles in search for diagnostic anatomic abnormalities that may reflect various compressive or inflammatory conditions. An ultrasound will be performed only if its clinically indicated, which is determined by the Neurologist performing the EMG/NCS study.

The UC Davis EMG Laboratory is located at: 

UC Davis Health Midtown Ambulatory Care Center
3160 Folsom Blvd. Suite 3100
Sacramento CA 95816

Parking Information: 

Patient parking is available in the parking garage, entrance is located on Folsom Blvd in the middle of the building. 
Once you have entered the parking garage you will see a sign pointing to the left that directs you toward the Valet parking and elevators. To the right will be the entrance to the self-parking structure. Turn right to park on the 4^th floor for the EMG lab Suite 3100 and it will take you to the 3^rd floor of the building. Please know your vehicle's license plate number to receive free parking validation for your visit. Validation is done at the front desk of the EMG Lab.

If you choose valet parking, the elevators are in the middle of the garage. Please park next to the elevators and the Valet staff will assist you. 

Take the elevator up to the third floor. Suite 3100 will be on your left.