What is a nerve conduction test? A nerve conduction test measures the speed and strength of electrical impulses as they move down a nerve. Healthy nerves can transmit signals at speeds up to 120 miles per hour. Nerve damage or a blockage in the conduction will slow and weaken this transmission. Doctors usually order nerve conduction testing in combination with another test, an EMG (electromyogram or electromyography). An EMG measures the electrical activity in muscles. Together, the two tests can show doctors the origin of nerve or muscle symptoms. An EMG will reveal problems with the muscle. A nerve conduction test will find problems with the nerves that supply the muscles. Other names for the test include nerve conduction velocity test and nerve conduction study. Why is a nerve conduction test performed? A nerve conduction test can identify nerve damage. It will show if a nerve is conducting signals to muscles the way it should. If the test is normal, the problem may be with the muscle itself. If the test is abnormal, nerve damage or a nerve disorder may be the culprit. Your doctor may recommend a nerve conduction test to find the cause of muscle or nerve symptoms. This includes stiffness, weakness, spasticity, numbness, tingling or pain. The test can evaluate nerve and muscle diseases and conditions including: ALS (amyotrophic lateral sclerosis) and myasthenia gravis Carpal tunnel and tarsal tunnel syndromes Guillain-Barre syndrome, Charcot-Marie-Tooth disease, and Lambert-Eaton syndrome Myopathies including muscular dystrophy Neuropathies including diabetic neuropathy and alcoholic neuropathy Spinal problems, such as herniated discs or sciatica There are many other potential nerve problems doctors can evaluate with a nerve conduction test. Talk with your doctor to understand exactly why you need the test and what the possible diagnosis could be. Who performs a nerve conduction test? A neurologist usually performs a nerve conduction test. A neurologist specializes in diseases and conditions of the brain and nervous system. This includes the spinal cord, nerves, muscles, and related blood vessels. Sometimes, doctors who perform this procedure are called electrodiagnosticians. A technologist may assist the doctor or perform some parts of the procedure. How is a nerve conduction test performed? A nerve conduction test is usually an outpatient procedure. Your doctor may even perform it as an office-based procedure. However, you may also have the test as part of a hospital stay to evaluate the cause of nerve symptoms. What to expect the day of your nerve conduction test In general, this is what happens the day of your nerve conduction test: You will need to remove all metal accessories, such as jewelry and eyeglasses, which could interfere with the test. Clothing with metal can also interfere. You can change into a patient gown if you need to remove clothing. You will be sitting or lying down for the test. The neurologist will locate the nerve needing testing. The doctor will place two electrodes on your skin at a specific distance apart over the nerve. One electrode sends out the signal and another one receives and records it. Using the distance, the doctor can know how fast the signal travels. Activating the stimulating electrode will send a mild electrical impulse to the nerve. It can produce brief pain, tingling and twitching. It may feel like the shock you get from static electricity. While the test can be uncomfortable, each impulse is very brief, lasting less than a millisecond. Once the test is over, you should not feel any pain or discomfort. The total time it takes to complete the testing depends on how many nerves the doctor needs to test. It can take anywhere from 15 minutes to over an hour. If you will also have an EMG, nerve conduction testing usually occurs first. What are the risks and potential complications of a nerve conduction test? A nerve conduction test is a very low-risk procedure. There are generally no complications from the testing, aside from discomfort during the test. Theoretically, nerve conduction testing impulses could possibly interfere with cardiac pacemakers and implantable cardiac defibrillators. However, there is no evidence it actually causes problems in people with these devices. To be safe, make sure your doctor knows if you have one of these devices. How do I prepare for a nerve conduction test? Nerve conduction testing does not require much preparation. Do not use oils, lotions, moisturizers, sunscreen or colognes or perfumes the day of your test. Your doctor may ask you to avoid these products for a few days before your test. Be sure to tell your doctor about all your medications. This includes prescriptions, over-the-counter drugs, herbal products, and supplements. Also, it’s important to know you must stay at a normal body temperature during the test. Being cold can slow nerve conduction. If you feel chilled, let your doctor know. Questions to ask your doctor Making a list of questions can help you remember everything you want to ask your doctor before nerve conduction testing. Questions you may want to ask include: Why do I need a nerve conduction test? What information will you get from a nerve conduction test? How many nerves do you need to test? How long will the testing take? Will you also do an EMG? How and when will I get the results? What other testing or procedures might I need? What can I expect after a nerve conduction test? Knowing what to expect makes it easier to plan and prepare for testing. How long will it take to recover? Generally, most people can return to their usual activities right after nerve conduction testing. In some cases, your doctor may advise you to avoid strenuous activities for the day of testing. Will I feel pain? Nerve conduction test pain or discomfort is usually brief. You should not feel any pain or discomfort once the testing is complete. When should I call my doctor? Ask your doctor about follow-up appointments after your nerve conduction test. Call your doctor’s office during normal business hours if you have questions between your testing and follow-up appointment. The results of your nerve conduction test will determine your next steps. Your doctor may recommend additional testing, procedures or treatments depending on the results.