EEG

EEG (electroencephalography) is a painless and non-invasive diagnostic test used to record the electrical activity of the brain. The purpose of an EEG is to show how the brain functions, which helps in diagnosing various neurological conditions. The procedure is completely safe and does not cause pain or permanent damage.

What is an EEG? 

EEG records the electrical impulses produced by brain cells (neurons). These impulses are displayed on a screen as wave-like patterns that reflect normal brain activity or possible abnormalities. Changes in brain activity patterns may indicate various conditions, including epilepsy, sleep disorders, and metabolic or inflammatory changes in the brain. EEG helps physicians better understand the functional state of the brain and plan further diagnostic tests or treatment.

How is an EEG test performed? 

The examination involves placing small electrodes on the scalp using a special paste or cap. The electrodes are connected to a computer that records the brain’s electrical activity in real time. During the examination, the patient usually sits or lies still and may be asked to open and close their eyes, breathe deeply, or look at a light source to help detect specific patterns of brain activity.

A standard EEG usually takes about 30 minutes.

An EEG after sleep deprivation (sleep-deprived EEG) lasts approximately 1.5 hours and is used when it is necessary to increase the likelihood of detecting abnormal brain waves, for example when epilepsy is suspected.

What is an EEG used for and which conditions does it help diagnose? 

EEG is used to diagnose and monitor various neurological conditions, including:

• epilepsy and other seizure disorders
• sleep disorders
• inflammatory or metabolic changes in the brain
• evaluation of brain function after injuries or in chronic neurological diseases
• monitoring brain activity when brain infections or neurodegenerative diseases are suspected

EEG helps physicians establish an accurate diagnosis, monitor the course of the disease, and choose the most appropriate treatment.

Read how to prepare for an EEG test.