Nerve Conduction Studies (NCS), Electromyography (EMG), 

Nerve Conduction Studies (NCS), Electromyography (EMG) is tests of the muscles and nerves in your arms and legs and the nerve cells that control them. 

Nerve conduction studies and electromyography, also referred to as a NCS or EMG test are tests that detect abnormalities in the integrity and function of the spinal cord, nerve roots, plexuses, and peripheral nerves. These tests objectively assess your nerves and muscles. Organic dysfunctions can be diagnosed, classified and prognostic evaluation made through use of NCS and EMG. NCS and EMG can also be used to evaluate muscle diseases and diseases affecting the spinal cord.

NCS and EMG should always be recorded by a qualified individual. This may either be an HPCSA registered Clinical Neurophysiologist or a HPCSA registered specialist Neurologist.

It is important that you know whether the person performing these tests is registered with the HPCSA. 

Nerve conduction studies

Nerve conduction studies can be performed either in the hospital or as outpatient tests. It may be done with or without an EMG also being performed.

NCS are non-invasive tests and is usually done while you or awake 

• How are these tests done:

During NCS test small electrode plates or stick-on electrodes will be placed over the muscles or nerves and small electrical impulses applied to your skin over your nerve. This will not damage the nerves, muscles or skin but may be uncomfortable to some patients as the stimulations will cause the target muscle to contract or the impulse will transmit between recording sites further along the nerve.

This impulse conduction will then be displayed on a computer screen where the neurophysiologist will be able to measure the responses.

Before the test, you’ll need to make sure your skin on your hands, feet, arms and legs is clean and doesn’t have any creams, oils or lotions on it. These products can interfere with the function of the electrodes.

Electromyography

Electromyography studies can be performed either in the hospital or as outpatient tests. It is usually done in conjunction with NCS but may be done without NCS also being performed.

• How are these tests done:

During the EMG test small electrode plates will be place over your muscles or a small thin needle electrode will be placed in one or more of your muscles one at a time. The needle EMG records the electrical activity in that muscle. The electrical activity recorded by the electrodes are then translated into graphs, sounds or numerical values on a computer screen that that can then be interpreted and assist your doctor in obtaining a correct diagnosis.

• Some reasons why your doctor may refer you for an NCS and EMG

Possible reasons for your doctor to refer you for NCS and EMG include:

• Tingling

• Numbness

• Muscle weakness

• Muscle pain or cramping

• Certain types of limb pain

Nerve conduction and EMG studies can aid in the diagnosis of degenerative nerve and muscle diseases (organic or toxic processes, hereditary or acquired pathologies such as autoimmune diseases) Neuromuscular junction disorders 

Sudden weakness or numbness in your hands of feet – peripheral neuropathies that can be caused by diseases like diabetes or Guillain Barre syndrome

Mechanical nerve compression or injury due to orthopaedic musculoskeletal abnormalities like carpal tunnel syndrome or sciatica. 

Evaluation of traumatic nerve injuries 

Pre and post-surgical evaluation of muscle or nerve injury or repair.