Table of ContentsView AllTable of ContentsUsesWhat to ExpectResultsFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Uses
What to Expect
Results
Frequently Asked Questions
Nerve conduction velocity (NCV), also called a nerve conduction study, is a noninvasive test that measures nerve function. This test involves small electrical shocks. It can be slightly uncomfortable but not painful—and it is safe.
An NCV is sometimes part of the evaluation of sensory problems, pain, and weakness of the extremities. It’s often done with anelectromyography (EMG), a nerve test that involves the placement of tiny needles into the muscles.
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This article describes what you can do to prepare for NCV, what to expect, and why you might have this test.
Nerve Conduction Velocity Test Uses
Generally, NCV is ordered to assess diseases of theperipheral nerves—those that connect from the muscles, organs, and skin to the spinal cord or brain. This test can be used to identify the type and location of nerve damage.
Often, peripheral nerve conditions cause pain, sensory loss, tingling, or burning. Sometimes, mild weakness and diminished reflexes are detected during a neurological examination.
Some of the conditions that are often evaluated with NCV are:
NCV testing does not help in the diagnosis of conditions that affect the brain, such as a stroke (blockage of a blood vessel or bleeding in the brain), meningitis (inflammation of the brain lining), a brain tumor, or Parkinson’s disease (progressive degeneration of the brain cells that produce the chemical messenger dopamine).
If your healthcare provider orders an NCV for you, it typically requires another appointment. This test usually is done in a clinic. Sometimes, NCV testing is performed in a hospital for evaluation of certain conditions, like GBS, which may require hospitalization.
You will not need to make any changes to your diet before having an NCV. You will be asked to avoid lotions or creams on your skin before the test.
If you are also having an EMG at the time of your NCV, you might be asked to stop taking medications or supplements that increase the risk of bleeding and bruising. If your healthcare provider says you can’t stop taking these medications for health reasons, you might be warned that you could have some bruising after the EMG test.
ContraindicationsFor some people who have electrical device implants, NCV may be contraindicated (advised against using). Make sure your healthcare providers are aware of your whole medical history.
Contraindications
For some people who have electrical device implants, NCV may be contraindicated (advised against using). Make sure your healthcare providers are aware of your whole medical history.
While it isn’t always possible, it can be helpful to wear clothes that provide access to the nerves that need to be tested in some situations. For example, if your test is to evaluate ulnar neuropathy, you can wear a shirt that can be rolled up to expose your arms.
Preparation
When you arrive for your test, you will be asked to sign a consent form, provide your order form, and show your identification and health insurance information. You might also have to pay a co-pay (a set amount paid for each healthcare service).
You will be led to the examination room where you will have your test, and you might be asked to take off your shoes and socks or change into a gown—this depends on which nerves you will have tested.
You may have your temperature, pulse, and blood pressure checked prior to your test.
During the Test
A physician typically will perform your NCV, and you might also have a technician present during your test. They might review your medical record and talk to you about your symptoms. They may also examine your muscle strength or sensation before your NCV. This would help your physician decide which nerves to test during your NCV.
You may be asked to lie down, and your skin will be cleaned, typically with an alcohol pad, on the areas where the electrodes will be placed.
For each nerve tested, you will have a small device, about the size of a toothbrush head, placed on your skin and another similar device placed on a different area of your skin.
You will be told when to expect a small shock sensation from the device. The sensation should go away within a few seconds. If more than one nerve is being tested, the process will be repeated for each nerve tested.
If you are having an EMG, this will be done after the NCV.
After the Test
After your test, you will be able to change or put your shoes back on. You can let the healthcare professional conducting the test know if you are feeling any discomfort or if you have any bleeding from the EMG needle (which is very rare). You should be able to leave to go home as soon as you are dressed.
Nerve Conduction Velocity Test Results
Your results will be ready in a report form about a week after the test.
An NCV test measures velocity (how fast a nerve transmits signals) and amplitude (how many nerve fibers were activated).These measurements are transmitted to a computer and shown as waves, as well as numerical values.
The values are compared to a standard measurement based on the nerve that’s being tested, the distance between the electrodes, and the person’s age. By comparison to the standard, the NCV results can identify certain patterns of nerve damage.
Outcomes of the NCV include:
Summary
A nerve conduction study (NCV) is a noninvasive test that measures the speed and strength of nerve stimulation, with the use of electrical probes placed on the skin. It is often part of the diagnostic process for evaluating nerve diseases.
Often, an electromyography (EMG), which is a needle test, is done at the same appointment. The results of NCV testing can be used to determine the type, severity, and location of nerve damage.
A Word From Verywell
After getting the results of your NCV study, you might need a combination of physical therapy, medical treatment, or a surgical procedure for the treatment of your condition. Most of the time, with treatment, painful symptoms of nerve diseases can improve. Treatment can often help stop the progression of conditions that cause nerve damage.
Frequently Asked QuestionsA normal NCV is determined based on the standard value for that nerve in the body (for example, theulnar nervein the arm or the sural nerve in the calf), the distance between the two devices, and the age of the person being tested.Many issues can affect NCV, including inflammation, nerve damage, nerve disease,demyelination, trauma to a nerve, and nutritional deficits. These factors affect nerves differently, and the NCV results will help determine what factors are affecting nerve function.In general, NCV is uncomfortable, but it is not a painful test. It may be more uncomfortable for people who have painful symptoms of peripheral neuropathy.
A normal NCV is determined based on the standard value for that nerve in the body (for example, theulnar nervein the arm or the sural nerve in the calf), the distance between the two devices, and the age of the person being tested.
Many issues can affect NCV, including inflammation, nerve damage, nerve disease,demyelination, trauma to a nerve, and nutritional deficits. These factors affect nerves differently, and the NCV results will help determine what factors are affecting nerve function.
In general, NCV is uncomfortable, but it is not a painful test. It may be more uncomfortable for people who have painful symptoms of peripheral neuropathy.
4 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ferdousi M, Kalteniece A, Azmi S, et. al.Corneal confocal microscopy compared with quantitative sensory testing and nerve conduction for diagnosing and stratifying the severity of diabetic peripheral neuropathy.BMJ Open Diabetes Res Care.2020;8(2):e001801. doi:10.1136/bmjdrc-2020-001801Shibuya K, Tsuneyama A, Misawa S, et al.Different patterns of sensory nerve involvement in chronic inflammatory demyelinating polyneuropathy subtypes.Muscle Nerve. 2022 Mar 20. doi:10.1002/mus.27530Tada K, Murai A, Nakamura Y, Nakade Y, Tsuchiya H.In carpal tunnel syndrome, sensory nerve conduction velocities are worst in the middle finger than in the index finger.Front Neurol. 2022;13:851108. doi:10.3389/fneur.2022.851108Tavee J.Nerve conduction studies: Basic concepts.Handb Clin Neurol.2019;160:217-224. doi:10.1016/B978-0-444-64032-1.00014-X
4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ferdousi M, Kalteniece A, Azmi S, et. al.Corneal confocal microscopy compared with quantitative sensory testing and nerve conduction for diagnosing and stratifying the severity of diabetic peripheral neuropathy.BMJ Open Diabetes Res Care.2020;8(2):e001801. doi:10.1136/bmjdrc-2020-001801Shibuya K, Tsuneyama A, Misawa S, et al.Different patterns of sensory nerve involvement in chronic inflammatory demyelinating polyneuropathy subtypes.Muscle Nerve. 2022 Mar 20. doi:10.1002/mus.27530Tada K, Murai A, Nakamura Y, Nakade Y, Tsuchiya H.In carpal tunnel syndrome, sensory nerve conduction velocities are worst in the middle finger than in the index finger.Front Neurol. 2022;13:851108. doi:10.3389/fneur.2022.851108Tavee J.Nerve conduction studies: Basic concepts.Handb Clin Neurol.2019;160:217-224. doi:10.1016/B978-0-444-64032-1.00014-X
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Ferdousi M, Kalteniece A, Azmi S, et. al.Corneal confocal microscopy compared with quantitative sensory testing and nerve conduction for diagnosing and stratifying the severity of diabetic peripheral neuropathy.BMJ Open Diabetes Res Care.2020;8(2):e001801. doi:10.1136/bmjdrc-2020-001801Shibuya K, Tsuneyama A, Misawa S, et al.Different patterns of sensory nerve involvement in chronic inflammatory demyelinating polyneuropathy subtypes.Muscle Nerve. 2022 Mar 20. doi:10.1002/mus.27530Tada K, Murai A, Nakamura Y, Nakade Y, Tsuchiya H.In carpal tunnel syndrome, sensory nerve conduction velocities are worst in the middle finger than in the index finger.Front Neurol. 2022;13:851108. doi:10.3389/fneur.2022.851108Tavee J.Nerve conduction studies: Basic concepts.Handb Clin Neurol.2019;160:217-224. doi:10.1016/B978-0-444-64032-1.00014-X
Ferdousi M, Kalteniece A, Azmi S, et. al.Corneal confocal microscopy compared with quantitative sensory testing and nerve conduction for diagnosing and stratifying the severity of diabetic peripheral neuropathy.BMJ Open Diabetes Res Care.2020;8(2):e001801. doi:10.1136/bmjdrc-2020-001801
Shibuya K, Tsuneyama A, Misawa S, et al.Different patterns of sensory nerve involvement in chronic inflammatory demyelinating polyneuropathy subtypes.Muscle Nerve. 2022 Mar 20. doi:10.1002/mus.27530
Tada K, Murai A, Nakamura Y, Nakade Y, Tsuchiya H.In carpal tunnel syndrome, sensory nerve conduction velocities are worst in the middle finger than in the index finger.Front Neurol. 2022;13:851108. doi:10.3389/fneur.2022.851108
Tavee J.Nerve conduction studies: Basic concepts.Handb Clin Neurol.2019;160:217-224. doi:10.1016/B978-0-444-64032-1.00014-X
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