Electromyography (EMG) involves the measuring of electrical activity within muscles by way of a needle electrode. It is rather similar to having an electrical microphone at the tip of the needle. Muscles are electrically active organs, and the signals and patterns of signals can lend additional information regarding the state of the muscle as well as the nerve supplying it.
In Australia, the person responsible for these tests is a neurologist, who frequently has had further training in the subspecialty of clinical neurophysiology.
Nerve conduction study
A nerve conduction study (NCS) involves activating nerves electrically with small safe pulses over several points on the skin, usually on the limbs, and measuring the responses obtained. Usually the response or signal is measured from the nerve itself or from a muscle supplied by the nerve being activated. This gives information about the state of health of the nerve, muscle and neuromuscular junction.