What Does EEG Mean?

During an EEG, electrodes are applied to your scalp.

The acronym EEG stands for electroencephalogram. An EEG is a noninvasive test that monitors the electrical signals occurring in the brain. Hans Berger, a German psychiatrist, performed the first EEG on a human brain in 1924.

Use

An EEG is helpful in diagnosing seizures and in evaluating tumors, Alzheimer's disease and other brain-related ailments. A doctor may also request an EEG when head injuries, mental confusion, unconsciousness or chronic insomnia occur, according to Medline Plus.

How It Works

Brain cells create electrical impulses when they communicate with each other, according to Medline Plus. The EEG works by following these impulses across the brain. Different states of consciousness produce different patterns of electrical activity in the brain, which allows an EEG to note whether a person is awake or sleeping. As reported in "The Secret Life of the Brain" by PBS, an EEG also reveals the length of time the brain takes in responding to stimuli.

Procedure

A patient having an EEG has electrodes applied to his scalp. These electrodes detect electrical activity in the brain, and, in the past, galvanometers received and measured the brain activity. These galvanometers were hooked to pens, and the pens traced the signal patterns onto moving graph paper, which was positioned beneath the pens. As of 2010, the electrodes placed on the scalp are hooked to an amplifier and recording machine, which convert the electrical signals and display them onto a computer screen.

References

• PBS: The Secret Life of the Brain: Scanning the Brain - EEG
• The University of Illinois at Chicago Department of Neurology: Dr. Hans Berger (1873-1941)
• Medline Plus: EEG

Resources

• Medline Plus: Health Topics