Electroencephalography, or EEG, monitors brain activity through the skull. EEG is used to help diagnose certain seizure disorders, brain tumors, brain damage from head injuries, inflammation of the brain and/or spinal cord, alcoholism, certain psychiatric disorders, and metabolic and degenerative disorders that affect the brain. EEGs are also used to evaluate sleep disorders, monitor brain activity when a patient has been fully anesthetized or loses consciousness, and confirm brain death.
This painless, risk-free test can be performed in a doctor’s office or at a hospital or testing facility. Prior to taking an EEG, the person must avoid caffeine intake and prescription drugs that affect the nervous system. A series of cup-like electrodes are attached to the patient’s scalp. These electrodes (also called leads) are small devices that are attached to wires and carry the electrical energy of the brain to a machine for reading.