An EEG (electroencephalogram) is a medical test that measures the electrical activity of the brain using small metal discs called electrodes that are attached to the scalp. Brain cells communicate with each other using electrical impulses, and this activity shows up as wavy lines on an EEG recording. An EEG is one of the main diagnostic tests for epilepsy, and it can also play a role in diagnosing other brain disorders. Some of the conditions that an EEG can help diagnose include:
- Epilepsy or another seizure disorder
- Brain tumors
- Brain damage from head injury
- Brain dysfunction that can have a variety of causes (encephalopathy)
- Sleep disorders
- Inflammation of the brain (encephalitis)
- Stroke
- Creutzfeldt-Jakob disease
An EEG can find changes in brain activity that might be useful in diagnosing brain disorders, especially epilepsy or another seizure disorder. It can also be used to confirm brain death in someone in a persistent coma, and to help find the right level of anesthesia for someone in a medically induced coma. An EEG is a safe and painless test that usually takes between 20 minutes to an hour and 15 minutes, depending on the type of EEG being performed. The EEG technologist attaches the electrodes to the scalp using a special adhesive, and the signals are transmitted wirelessly to a computer. The EEG recording must be analyzed by a neurologist, who then sends the results to the doctor.
