An electroencephalogram (EEG) is a test that detects electrical activity in your brain using small, flat metal discs (electrodes) attached to your scalp. Your brain cells communicate via electrical impulses and are active all the time, even when you’re asleep. This activity shows up as wavy lines on an EEG recording.
Electromyography (EMG) is a diagnostic procedure to assess the health of muscles and the nerve cells that control them (motor neurons). Motor neurons transmit electrical signals that cause muscles to contract. An EMG translates these signals into graphs, sounds or numerical values that a specialist interprets.
A nerve conduction study (NCS), also called a nerve conduction velocity (NCV) test–is a measurement of the speed of conduction of an electrical impulse through a nerve. NCS can determine nerve damage and destruction. During the test, the nerve is stimulated, usually with surface electrode patches attached to the skin.