What Are NCS and EMG?

 

Nerve Conduction Studies (NCS) and Electromyography (EMG) are diagnostic tests used to assess the health and function of your nerves and muscles. These tests help identify conditions affecting the peripheral nervous system, muscles, and neuromuscular junction. 

 

• Nerve Conduction Studies (NCS) measure how well electrical signals travel along your nerves. This helps detect nerve damage, compression, or dysfunction.

• Electromyography (EMG) records the electrical activity of muscles, providing information about whether muscle weakness is due to nerve problems or a primary muscle disorder.

 

These tests are often performed together as part of a comprehensive neurological evaluation.

 

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Why Might You Be Referred for an NCS or EMG?

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These tests may be recommended if you experience:

 

• Numbness or tingling in your hands, feet, or limbs

• Weakness in your arms or legs

• Muscle cramps, twitching, or spasms

• Unexplained pain, burning, or electric shock sensations

• Difficulty gripping objects or walking

 

NCS/EMG are used to help diagnose conditions such as:

 

• Carpal tunnel syndrome (nerve compression at the wrist)

• Ulnar neuropathy (nerve compression at the elbow)

• Radiculopathy (pinched nerves in the spine, often due to a herniated disc)

• Peripheral neuropathy (nerve damage due to conditions such as diabetes, infections, or autoimmune diseases)

• Motor neuron diseases (such as amyotrophic lateral sclerosis, ALS)

• Guillain-Barré syndrome (an autoimmune disorder affecting nerves)

• Myasthenia gravis (a disorder affecting nerve-muscle communication)

• Muscle diseases (such as muscular dystrophy or myositis)

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Who Refers Patients for These Tests?

 

Patients may be referred for NCS and EMG by a variety of specialists. These tests are used to assist in diagnosing and managing conditions across different medical fields, including but not exclusive to:

 

Neurologists: As specialists in nerve and muscle disorders, neurologists frequently request these tests to evaluate conditions such as neuropathy and other peripheral nerve disorders, myopathy and other neuromuscular disorders, myasthenia gravis, and motor neuron disease.

 

Orthopaedic Surgeons and Neurosurgeons: If you have symptoms related to nerve compression, joint disorders, or spinal problems (e.g., carpal tunnel syndrome, nerve impingement), your orthopaedic surgeon may request these tests to guide treatment decisions. If you have a suspected pinched nerve in the spine causing radiculopathy, or are being evaluated for spinal surgery, these tests help determine the extent of nerve involvement.

 

Rheumatologists: Patients with inflammatory or autoimmune conditions affecting the muscles and nerves, such as myositis or vasculitic neuropathy (muscle or nerve damage related to inflammation), may be referred for testing.

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General Practitioners (GPs): If you report symptoms such as numbness, tingling, weakness, or unexplained pain, your GP may refer you for testing to determine if an underlying peripheral nerve condition is present. If you have suspected diabetes-related neuropathy, your doctor may request an NCS to assess nerve function.

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What to Expect During the Tests

 

Nerve Conduction Study (NCS)

 

Electrodes will be placed on your skin over the nerves being tested. Small, controlled electrical pulses will be applied to stimulate the nerve. The response is recorded to measure nerve signal speed and strength.

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You may feel a mild tingling or twitching sensation, but the test is generally not painful.

 

Electromyography (EMG)

 

A fine, disposable sterile needle is inserted into selected muscles to measure electrical activity. You may be asked to contract and relax your muscles while recordings are taken.

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This test helps to analyse muscle activity at rest and when contracted. This provides information to aid the diagnosis of an underlying nerve or muscle disorder. Some discomfort may be felt during needle insertion, but the procedure is safe and typically well tolerated.

 

​The NCS and EMG test typically takes between 20-40 minutes.

 

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How to Prepare for NCS and EMG

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• Avoid applying lotions, oils, or creams on the day of the test, as these can interfere with electrode placement.

• Wear loose, comfortable clothing to allow easy access to the arms and legs.

• Wear covered shoes or gloves during cold weather as cool limb temperatures can affect the conduction of nerves.

• Inform us if you take blood thinners, have a pacemaker, or implanted electrical device.

• There is no fasting required, and you can eat and take your medications as usual.

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After the Test

 

The results will be analysed and discussed with you or your referring doctor. A brief explanation of the findings can usually be provided before the end of the appointment, although in more complex cases, further analysis may be required before a final report can be issued.

 

Copies of the report will be provided to both you and the consultant who referred you for the test. Depending on the findings, further tests or treatment options may be recommended by your primary consultant.

 

Some minor soreness and bruising may be experienced at the sites where EMG was performed but most people can resume normal activities without any significant limitations immediately after the test.