Electromyography (EMG) and Nerve Conduction Studies

What is Electromyography (EMG) and Nerve Conduction Studies?

Electromyography (EMG) and Nerve Conduction Studies (NCS) are medical tests that assess the function of the muscles and the nerves. It can be used to help diagnose neuromuscular disorders such as muscular dystrophy, carpal tunnel syndrome, amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease, and peripheral neuropathy.


Prior to an electromyography and nerve conduction study, no specific preparation is necessary. You may be asked to remove any jewelry, watches, or other metal objects that can interfere with the examination.


The EMG-NCS procedure typically takes 30-45 minutes. The patient will be asked to lie on a table. Small electrodes are placed onto the skin overlying the nerve or muscle being studied. A low-voltage current is then applied to the nerve. This current causes the muscles to contract. The EMG then records the electrical activity emanating from the muscle and also how quickly the muscle contracts and relaxes.


  • Needle Electromyography
  • Nerve Conduction Studies


The risks associated with EMG and NCS tests are minimal. It is possible to experience mild discomfort or muscle twitching during the procedure.


EMG and NCS tests are used to detect nerve and muscle damage, impairments, or diseases. It can be used to distinguish between muscle and nerve disorders and to help diagnose nerve entrapment syndromes such as carpal tunnel syndrome.


EMG-NCS are usually requested by your doctor if you are experiencing any of the following: numbness, weakness, pain, or tingling in your arms or legs. It may also be recommended in cases of unexplained muscle weakness or if there is an injury to a nerve or muscle.