Electrodiagnostic testing can help determine the source of a problem with your nerves and muscles. Nerve conduction studies (NCS) use small electrical pulses to help measure the way nerves conduct electrical signals, and can determine if a nerve is injured, pinched, or normal. Electromyography (EMG) uses a small needle similar to those used in acupuncture to measure the activity of muscles during movement. These studies can be used in combination with imaging to determine the most likely source of pain, and also to guide your treatment.