Electromyography (EMG) and nerve conduction studies (NCS) are performed to assess the function of the nerves and muscles. The information obtained during this test is used to help determine the cause of your symptoms. During EMG/NCS testing, the neurologist places surface electrodes at various locations on your skin depending on where you’re symptoms. The neurologist may insert a needle electrode at various sites in the arms, legs or elsewhere depending on your symptoms. EMG is a low-risk procedure and complications are rare. There’s a small risk of bleeding, infection and nerve injury where a needle electrode is inserted.
EMG and NCS are used to evaluate patients primarily with symptoms of numbness, weakness, muscle atrophy and/or pain in the arm or leg. EMG/NCS testing commonly detects:
- Pinched nerves such as carpal tunnel syndrome, ulnar neuropathy, peroneal neuropathy
- Pinched nerves in the spine as in radiculopathy
- Neuropathy including diabetic neuropathy, Guillan Bare, multifocal motor neuropathy, mono neuritis multiplex and CIDP
- Motor neuron diseases such as ALS
- Muscle disease such as inflammatory myopathy or toxic myopathy (e.g. statins)
- Brachial plexus or lumbosacral plexus disorders