NCS & EMG tests
Nerve Conduction Study (NCS)
A Nerve Conduction Study (NCS) is a test that evaluates the function of the peripheral nerves by measuring the speed and strength of electrical signals traveling through them. It helps detect abnormalities in the nerves and pinpoint the location and severity of nerve damage.
During a nerve conduction study, small electrical currents are applied to specific nerves using surface electrodes placed on the skin. These electrical impulses stimulate the nerves, and the resulting responses are recorded and analyzed.
How is an NCS test performed?
During the test, surface electrode patches are placed on the skin along the path of the nerve being studied. One electrode delivers a small electrical impulse to stimulate the nerve, while the other records the response. The time it takes for the electrical signal to travel between the electrodes is measured to calculate the nerve conduction velocity. The procedure is repeated for multiple nerves, depending on the symptoms and the area of concern..
What conditions can NCS detect?
NCS is commonly used to diagnose:
Carpal tunnel syndrome (compression of the median nerve in the wrist)
Peripheral neuropathy (nerve damage caused by conditions like diabetes)
Guillain-Barré syndrome (a rare autoimmune disorder affecting nerves)
Herniated discs causing nerve compression Charcot-Marie-Tooth disease (a hereditary condition affecting nerve function)
Carpal tunnel syndrome (compression of the median nerve in the wrist)
Peripheral neuropathy (nerve damage caused by conditions like diabetes)
Guillain-Barré syndrome (a rare autoimmune disorder affecting nerves)
Herniated discs causing nerve compression Charcot-Marie-Tooth disease (a hereditary condition affecting nerve function)
Electromyography (EMG)
Electromyography (EMG) is a diagnostic procedure that evaluates the health of muscles and the nerve cells that control them, called motor neurons. It measures the electrical activity generated in muscles in response to nerve stimulation, helping diagnose neuromuscular disorders.
How is an EMG test performed?
During the EMG test, one or more fine needles (electrodes) are inserted into specific muscles. These electrodes detect electrical signals produced by muscle cells when they are at rest and when they contract. A monitor, called an oscilloscope, displays these signals as visual waveforms, and an audio amplifier allows the electrical activity to be heard. The procedure assesses muscle activity during three states:
1. At rest – to detect any spontaneous electrical activity, which may indicate a nerve or muscle problem.
2. With mild contraction – to analyze how the muscle responds to minimal nerve stimulation.
3. With strong contraction – to measure the muscle’s performance under full activity.
2. With mild contraction – to analyze how the muscle responds to minimal nerve stimulation.
3. With strong contraction – to measure the muscle’s performance under full activity.
What conditions can EMG detect?
EMG is primarily used to diagnose:
1. Neuropathy (nerve damage)
2. Radiculopathy (nerve root issues, such as in herniated discs)
3. Muscle diseases such as muscular dystrophy
4. Neuromuscular junction disorders like myasthenia gravis
5. Motor neuron diseases like amyotrophic lateral sclerosis (ALS)
1. Neuropathy (nerve damage)
2. Radiculopathy (nerve root issues, such as in herniated discs)
3. Muscle diseases such as muscular dystrophy
4. Neuromuscular junction disorders like myasthenia gravis
5. Motor neuron diseases like amyotrophic lateral sclerosis (ALS)
EMG and NCS Together
EMG and NCS are often performed together as complementary tests. While EMG focuses on detecting abnormalities in muscle activity and nerve-to-muscle communication, NCS assesses the efficiency of nerve signaling.
This combination provides a comprehensive evaluation of neuromuscular health and is invaluable in diagnosing and managing conditions like:
1. Neuromuscular junction disorders
2. Nerve root compression
3. Hereditary or degenerative nerve and muscle diseases
Both tests are safe and carry minimal risk, with temporary discomfort from needle insertion or electrical stimulation being the most common experience.
This combination provides a comprehensive evaluation of neuromuscular health and is invaluable in diagnosing and managing conditions like:
1. Neuromuscular junction disorders
2. Nerve root compression
3. Hereditary or degenerative nerve and muscle diseases
Both tests are safe and carry minimal risk, with temporary discomfort from needle insertion or electrical stimulation being the most common experience.
