What is a Nerve Conduction Study?

A nerve conduction study (NCS) involves safely electrically activating nerves with small pulses on several points of the skin and measuring their response. This assessment provides information on the health of the nerve, muscle and the junction that connects them (neuromuscular junction).

Electromyography (also known as EMG) uses a needle electrode to measure the electrical activity in muscles. This information provides information about how well the muscle and nerve are functioning.

When is the NCS/EMG used?

An NCS/EMG is suggested if you are experiencing symptoms that may suggest a problem with either the nerves or muscles. These problems may come in the form of tingling, numbness, weakness or pain, even when the physical examination is considered normal.

Even if the test does not find any abnormalities, it is still useful for ruling out certain conditions.

Conditions NCS/EMG may help diagnose include:

• Nerve disorders – such as carpel tunnel or other trapped nerves.
• Nerve roots – most commonly in the neck and lower back.
• Plexus disorders
• Muscle disorders
• Neuromuscular junction disorders

The procedure

Electrodes will be attached to your skin in positions decided by your doctor. Electrical impulses are then sent through the electrodes and your response recorded.

With an EMG, a small needle is inserted through the skin into the muscle belly and an electrical impulse is delivered. The response is then recorded. Local anaesthetic is generally not required.

What are the risks?

Generally, few risks are associated with the procedure. Some discomfort is experienced during the procedure but no complications are expected after.