Nerve Conduction Study

What is a nerve conduction study?

Nerve conduction studies (NCS) measure the rate at which electrical impulses move through your nerves. This is an important diagnostic procedure, being able to help diagnose neurological disorders which affect the nerves. In our bodies, nerves control the muscles, and electrical impulses are constantly transmitted between nerves and muscles.

In an NCS, the speed of conduction of electrical impulses along your peripheral nerves is measured, and small patches which deliver electrical pulses will be attached to your skin. Another test that is often done with an NCS is an electromyography (EMG). This test measures the electrical activity in your muscles. Both of these tests can work together to diagnose the disorders you might have and the extent of damage that might be done to your nerves and muscles.

Why may you need nerve conduction studies?

An NCS is often used together with an EMG, in order to tell the difference between a nerve disorder and a muscle disorder. The NCS is used to detect any issues with your nerves, and the EMG can detect if the muscles respond properly to the nerves. 

Some of the conditions that can be diagnosed with an NCS include:

• Myopathy. Myopathy is a general term that refers to diseases that affect muscles in the body, also known as neuromuscular disorders.
• Motor neurone disease (MND). MND refers to a group of neurodegenerative diseases that deteriorate your body’s motor neurons, causing the nerves in your spine and brain to gradually lose function over time.
• Peripheral neuropathy. Peripheral neuropathy refers to conditions resulting from damage to the peripheral nerves. The peripheral nerves are the network of nerves outside the brain and spinal cord, and they work to send information from the brain and spinal cord to other parts of the body.
• Sciatica is pain caused by irritation or compression of the sciatic nerve. 

What happens during a nerve conduction study?

During an NCS, a number of electrodes will be placed on your skin, on different areas which are along your peripheral nerves. 

Small electrical shocks will then be generated, to stimulate your nerves at one site and record the electrical current received at a different site. You will need to relax so that the results are recorded accurately

From this, we can determine if the nerve is conducting electrical impulses as expected. Each electrical stimulation is tracked on a computer and analysed by the electromyographer who is carrying out the test.  This process may cause you some discomfort depending on the strength of the electrical stimulation, but is usually painless. 

What to do before a nerve conduction study?

Before an NCS, do clarify any queries or concerns you have with your doctor before coming to your scheduled appointment. There are no restrictions on dietary and fluid intake before the procedure and you may eat, drink, or take your medications per normal.

Let your doctors and nurses know if you are on any blood-thinning medications, other anticoagulants, any antibiotics or if you have a pacemaker or bleeding disorder that you know of.

You can take a shower before coming to your appointment, but do not use lotion on your skin, as this might interfere with the NCS. The doctor might warm your body before the diagnostic test by using a blanket or warm water to heat up your skin. 

Are there any risks and side effects of a nerve conduction study?

There are generally very few risks like mild pain or transient discomfort of this procedure. Any risks specific to your case will be explained to you before the test. 

What do I do after a nerve conduction study?

Generally, after an NCS is conducted, you will be able to return to your normal daily activities, unless otherwise instructed by your doctor.