There are various conditions that can cause muscle twitching. Minor muscle twitching is usually the result of less serious, lifestyle-related causes. More severe muscle twitching, however, is often the result of a serious condition.
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air).
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.