What is an NCV/EMG?
An NCV/EMG test is a diagnostic test that your doctor may order to assist in obtaining additional information in order to assist him/her in making the right diagnosis regarding your medical condition. The test has two components, the first is the NCV (nerve conduction test), the second component is the needle examination called an electromyogram. An electromyogram, or EMG, is a test that checks the response of muscles to messages sent by the nerves.
What type of patient needs an NCV/EMG?
Patients present with a lot of complaints, but the ones that require a nerve test (NCV/EMG) are those that complain of neck or back pain with radiating pain in the arm or legs, muscle weakness or involuntary twitching of muscles. Patients that complain of burning pain in the feet, hands or fatigue with minimal exertion are excellent candidates for the test.
What types of conditions are diagnosed with NCV/EMG?
Patients that have neck pain hand or arm numbness or tingling are usually referred for the test. Your doctor may want to exclude the following:
- Carpal tunnel syndrome,
- Ulnar neuropathy at the wrist or elbow,
- Pinched nerve (cervical radiculopathy),
- Brachial plexus injury,
- Radial neuropathy,
- Thoracic outlet syndrome,
- Myopathy (muscle weakness), or
- Myofascial referred pain.
Patents that have back pain with lower extremity pain may have the following:
- Lumbosacral radiculopathy,
- Peroneal neuropathy,
- Sciatic neuropathy,
- Tarsal tunnel syndrome, or
- Lumbosacral plexopathy.
How do I prepare for an electromyogram?
Tell your health care provider before the test if:
- You have any bleeding problems,
- You have a pacemaker,
- You have allergies, or
- You are taking any medicines.
On the day of the test, take a shower to remove body oil and do not use body lotion.
How is the test performed?
The first part of the test requires the doctor to isolate specific nerves with precisely placed electrodes and then he /she will provide a low voltage electrical stimulus to activate or depolarize the nerve. The doctor will evaluate different nerves in the extremity, protocols vary, but be prepared to have about 4-6 nerve stimulated. The second phase of the test is the needle examination study in which the doctor places a thin needle into 4-6 different muscles to look for muscle abnormality.
When can I expect the results of the test?
The typed EMG results can be faxed to your doctor within 24 hours.