Nerve Conduction Study (NCS) and Needle Electromyography (EMG)

What are Nerve Conduction Study (NCS) and Needle Electromyography (EMG)?

NCS and EMG are tests that assess the health of your nerves and muscles.

NCS measures the flow of electrical impulses along a nerve to check the nerve function. EMG checks the electrical activity in your muscles.

Your doctor may recommend these tests to:

• Workup for symptoms of numbness, tingling, weakness or muscle cramps.
• Assess nerve damage or muscle disorders.

This list is non-exhaustive.

How should I prepare for NCS and EMG?

Before the day of test

• Not required to fast
• Continue with your regular diet and medications (unless instructed differently by your doctor).
• Please inform the neurodiagnostic laboratory managing your test  if you have an implanted electronic device, such as a heart pacemaker, defibrillator, intracranial device, or neurostimulator.

On the day of test

• Do not apply body lotion on your arms and legs.
• Wear loose shirts, blouses, bermuda shorts or shorts.
• Inform our staff if you are on anti-coagulant medications (blood-thinners) such as warfarin, heparin, apixaban, dabigatran, rivaroxaban.

How are NCS and EMG performed?

NCS is performed by a neurotechnologist and will take approximately 30-60min (depending on the areas to be tested).

• This test is usually done while you are lying down on the bed.
• Electrode patches (sticky pads) are placed on the skin overlying the muscle of the nerve being tested in the upper and/or lower limbs.
• A stimulator is placed on the skin to stimulate the nerve at various points along the upper and/or lower limbs. You will feel brief, mild electric sensations over the stimulation points, which may cause discomfort, but it is safe.
• The electrical activity in the nerve is detected by the electrodes and recorded.
• This process is repeated over other parts of the limbs, depending on the nerves to be tested.
• For accurate test results, try to remain still, unless otherwise instructed. You may be asked to move your limbs during the test.
• Once this test is done, further testing with electromyography may be required. If electromyography is not required, the electrodes are removed, and the skin is cleaned.
• A detailed report will be sent to your doctor within two weeks. Your doctor will discuss the findings with you at your next appointment.

EMG is performed by an EMG-trained neurologist and takes approximately 30 min.

• This test is usually done while you are lying down on the bed.
• The skin overlying the muscle is disinfected with an alcohol swab.
• A thin, disposable sterile needle is inserted into the muscle(s). You may feel slight discomfort during this process.
• After the needle is inserted, you will be asked to do some light contractions using the muscle.
• The electrical signals in the muscle are recorded by the needle.
• This process may be repeated over various muscles of the body e.g. arms, legs accordingly.
• Once the test is done, the needle is removed, and any bleeding is compressed. You can go home after. 
• You may experience some minor bruising. It is normal for your muscles to feel sore after the test, but it should get better after a few days. If you feel severe pain, swelling or persistent bleeding in the muscles, please inform the neurodiagnostic laboratory managing your test.
• A detailed report will be sent to your doctor within two weeks. Your doctor will discuss the findings with you at your next appointment.

Frequently Asked Questions about NCS and EMG

Are the tests safe?

The tests are generally safe although some patients may experience discomfort. The neurotechnologist and doctor will be with you throughout the process. If you feel unwell, speak to the neurotechnologist or doctor.

It is normal for your muscles to feel sore after the EMG, but it should get better after a few days. If you feel severe pain or swelling at the site, please inform us.

Can I use Medisave to pay for these tests?

These tests may be claimable under:

• Flexi-MediSave for Seniors; or
• Outpatient scans for diagnosis or treatment of a medical condition. 

Please refer to the Ministry of Health's Outpatient Care page for the latest claim limits and eligibility criteria.

The information is correct as of July 2026 and subject to revisions without notice.
Content adapted from NNI Neurodiagnostic Laboratory (NDL), NNI@TTSH.