HomeScienceNeuroscienceWhat is EEG?
Science·2 min·Updated Mar 12, 2026

What is EEG?

Electroencephalography

Quick Answer

Electroencephalography, or EEG, is a technique used to record electrical activity in the brain. It involves placing small electrodes on the scalp to measure brainwaves, helping to understand brain function and diagnose conditions.

Overview

Electroencephalography (EEG) is a method that captures the electrical activity of the brain using electrodes placed on the scalp. These electrodes detect tiny electrical signals produced by neurons, which are the brain's nerve cells. By analyzing these signals, researchers and doctors can learn about brain function and identify issues like seizures, sleep disorders, and other neurological conditions. The way EEG works is relatively straightforward. When neurons communicate with each other, they generate electrical impulses that can be measured on the surface of the scalp. The EEG machine amplifies these signals and displays them as waveforms on a monitor, allowing specialists to interpret the patterns. For example, a person experiencing a seizure may show specific wave patterns that indicate abnormal brain activity, which can be crucial for diagnosis and treatment. EEG is significant in the field of neuroscience because it provides real-time insights into brain activity without needing invasive procedures. This non-invasive nature makes it a valuable tool for both clinical and research purposes. For instance, scientists studying sleep can use EEG to observe how brainwaves change during different sleep stages, helping to uncover the mysteries of sleep and its impact on overall health.


Frequently Asked Questions

EEG is commonly used to diagnose conditions like epilepsy, sleep disorders, and brain tumors. It helps doctors understand abnormal brain activity that may indicate these conditions.
EEG is a safe procedure and is generally painless. The electrodes used are non-invasive and simply adhere to the scalp, causing no discomfort.
An EEG test usually takes about 20 to 40 minutes, but it can vary depending on the specific requirements of the test. Some tests may require longer monitoring, especially if the patient is having seizures.