A nerve conduction study (NCS), also known as a nerve conduction velocity (NCV) test, is a diagnostic procedure used to assess the functionality of peripheral nerves in the body. These peripheral nerves are the ones located outside the central nervous system, which includes the brain and spinal cord.
During the NCS, a nerve is stimulated by attaching electrode patches to the skin. Two electrodes are strategically placed over the nerve of interest. One electrode delivers a mild electrical impulse to stimulate the nerve, while the other records the resulting electrical activity. This process is repeated for each nerve under examination.
The test calculates nerve conduction speed by measuring the distance between the electrodes and the time it takes for electrical impulses to travel between them. More specifically, the NCS assesses the flow of electrical current through two types of nerves:
An NCS may be recommended by your healthcare provider if you experience symptoms such as tingling or numbness in various parts of your body, including the arms, legs, hands, feet, and face. Depending on your specific situation, you may undergo this study in an outpatient setting or as part of your hospital stay. Typically, NCS is performed in conjunction with an Electromyography (EMG) test for a comprehensive evaluation of nerve and muscle function.
Nerve conduction studies diagnose peripheral nerve issues, like neuropathy and nerve compression. They determine the cause, severity, and prognosis of these conditions.
The electrical pulses used in NCV tests are typically very low in voltage, but the potential risks associated with the procedure can vary based on your individual medical condition. It is crucial to address any concerns with your healthcare provider beforehand. Several factors, such as spinal cord damage, severe pre–test pain, and body temperature, may affect the accuracy of NCV results. Additionally, it’s important to inform your healthcare provider if you have a cardiac defibrillator or pacemaker, as special precautions may be necessary.
Nerves function like cables, transmitting electrical signals from the brain to the body’s organs, allowing muscle movement and sensations. In a nerve conduction study, electrodes are placed on the skin along the nerve’s path, and a mild electrical shock stimulates the nerve. This test measures the strength and speed of the electrical impulses. Motor nerve responses are measured in the controlled muscles, while sensory nerve responses are recorded elsewhere along the nerve.
Healthy nerves conduct electrical signals at speeds up to 120 miles per hour. Damage to the nerve results in weaker and slower signals. By stimulating the nerve at multiple points, healthcare providers can pinpoint the location of the damage.
Electromyography (EMG) is a similar test that measures muscle electrical activity and is often performed alongside nerve conduction studies. These tests help identify the presence, location, and severity of muscle and nerve disorders.
Before undergoing a nerve conduction study, it is important to:
The procedure for a nerve conduction study can vary based on the specific purpose of the test and which nerves are being evaluated. However, generally, you can anticipate the following steps during a nerve conduction study:
Following the completion of the test, the adhesive paste securing the electrodes to your skin will be removed. Typically, you can resume your usual activities unless your healthcare provider recommends otherwise, which may include avoiding strenuous activities for the remainder of the day. Furthermore, additional post–procedure instructions may be provided by your healthcare provider based on your specific circumstances.
Nerve conduction studies, while valuable for diagnosis, may not be standalone diagnostic tools. Healthcare providers typically assess the results in conjunction with additional tests, the patient’s medical history, and their symptoms to arrive at a diagnosis. When a patient displays signs of nerve injury or damage, a nerve conduction study can offer supplemental insights to the healthcare provider, aiding in both diagnosis and treatment planning.
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