A nerve conduction study (NCS) evaluates nerve function, assessing nerve health and identifying potential issues.
What is a Nerve Conduction Study?
A nerve conduction study measures how quickly electrical signals travel through peripheral nerves. These nerves extend outside the brain and spinal cord, playing a role in sensation and muscle movement. The test helps detect damage or dysfunction in these nerves.
Healthcare providers use NCS to diagnose various conditions that affect the nerves. These conditions include carpal tunnel syndrome, peripheral neuropathy, and Guillain-Barré syndrome. Often, an NCS is performed alongside an electromyography (EMG) test, which assesses muscle activity, to determine if symptoms stem from a nerve or muscle disorder.
What Does the Test Feel Like?
During a nerve conduction study, individuals experience distinct sensations from electrical impulses. Most describe these as a brief, mild electrical shock, often compared to static electricity after touching a metal object.
The electrical stimulation can cause a tingling, buzzing, or twitching sensation in the muscle controlled by the stimulated nerve. While startling or uncomfortable, these sensations are generally described as discomfort rather than intense pain. Some may feel a sharp tapping or brief burning sensation.
Individual tolerance varies. While some find it significantly uncomfortable, many patients report the test was not as difficult as anticipated. Any discomfort is brief and resolves quickly once the electrical pulse stops.
Preparing for and Undergoing the Test
Preparation
Patients should bathe or shower before the test. Avoid applying lotions, creams, perfumes, or oils to the skin on the day of the test, as these can interfere with electrode adhesion and test accuracy.
Wearing loose-fitting clothing is recommended for easy access to tested areas. Maintaining a normal body temperature is also important, as cold skin can affect nerve conduction velocity and influence results. Patients should inform their healthcare provider about any implanted electrical devices, such as pacemakers, or if they are taking blood-thinning medications, as special precautions may be necessary.
During the Test
During the test, the patient will sit or lie down. A healthcare provider places adhesive electrodes on the skin over the nerves. One electrode delivers a mild electrical impulse to stimulate the nerve, while other electrodes record the nerve’s response and signal speed.
This process is repeated for each nerve, and the procedure can take 15 minutes to over an hour, depending on the number of nerves examined. Patients can communicate any significant discomfort to the technician during the test.