Nerve conduction velocity

Adhesive patches called surface electrodes are placed on the skin over nerves or muscles at different spots. A very mild electrical impulse is applied via other patches or a handheld stimulator to stimulate the nerve. The resulting electrical activity of the nerve is recorded by the electrodes. The distance between…

You must stay at a normal body temperature. Being too cold alters nerve conduction and can give false results. Tell your health care provider if you have a cardiac defibrillator or pacemaker, or other implanted device such as a deep brain stimulator. Special steps may need to be taken before the test if you have one…

The impulse may feel like an electric shock. You may feel some discomfort depending on how strong the impulse is. You should feel no pain once the test is finished. Often, the nerve conduction test is followed by EMG. In this test, a needle is placed into a muscle and you are told to contract that muscle. This process…

This test is used to diagnose nerve damage or destruction. The test may sometimes be used to evaluate diseases of nerve or muscle, including: Myopathy Lambert-Eaton syndrome Myasthenia gravis Carpal tunnel syndrome Tarsal tunnel syndrome Diabetic neuropathy Bell palsy Guillain-Barré syndrome Brachial plexopathy

NCV is related to the diameter of the nerve and the degree of myelination (the presence of a myelin sheath on the nerve fiber) of the nerve. Newborn infants have values that are approximately half that of adults. Adult values are normally reached by age 3 or 4. Note: Normal value ranges may vary slightly among…

Most often, abnormal results are due to nerve damage or destruction, including: Axonopathy (damage to the long portion of the nerve cell) Conduction block (the impulse is blocked somewhere along the nerve pathway) Demyelination (damage and loss of the fatty insulation surrounding the nerve cell) The nerve damage or…

An NCV test shows the condition of the best surviving nerve fibers. Therefore, in some cases the results may be normal, even if there is nerve damage.

Deluca GC, Griggs RC. Approach to the patient with neurologic disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 26th ed. Philadelphia, PA: Elsevier; 2020:chap 368. Nuwer MR, Pouratian N. Monitoring of neural function: electromyography, nerve conduction, and evoked potentials. In: Winn HR, ed. Youmans…