An electroencephalogram (EEG) is a procedure that measures the electrical impulses in the brain. An EEG is done by placing electrodes, flat metal disks that are small sensors, on a person’s scalp to detect the electrical impulses moving through the brain.

An EEG is often used to help determine the presence and cause of seizures. The amount and pattern of electrical activity is important in diagnosing seizure disorders.

Brain cells communicate with each other by producing tiny electrical signals, called impulses. An EEG measures this activity. The test is done by an EEG specialist in a physician’s office or at a hospital or laboratory.

Flat metal disks called electrodes are placed all over the patient’s scalp. The disks are held in place with a sticky paste. The electrodes are placed all over the patient’s scalp and are held in place with a sticky paste. The electrodes are connected by wires to a speaker and recording machine that changes the electrical signals into patterns of wavy lines that can be seen on a computer.

Reasons for the Test

EEG is used to look at your brain activity. In addition to helping diagnose seizures, it may also be used to diagnose or monitor the following health conditions:

  • Abnormal changes in body chemistry that affect the brain
  • Brain diseases such as Alzheimer’s disease
  • Confusion
  • Head injuries
  • Infections
  • Tumors
  • Evaluate problems with sleep (sleep disorders)
  • Investigate periods of unconsciousness
  • Monitor the brain during brain surgery