Arteriovenous Malformation Support Group

Overview

An electroencephalogram (EEG) is a noninvasive test that records electrical patterns in your brain. The test is used to help diagnose conditions such as seizures, epilepsy, head injuries, dizziness, headaches, brain tumors and sleeping problems. It can also be used to confirm brain death.

How does an EEG work?

The billions of nerve cells in your brain produce very small electrical signals that form patterns called brain waves. During an EEG, small electrodes and wires are attached to your head. The electrodes detect your brain waves and the EEG machine amplifies the signals and records them in a wave pattern on graph paper or a computer screen (Fig. 1).

There are several different ways to conduct an EEG:

What does an EEG show?

Overview

An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels in the brain or spine. Some AVMs have no specific symptoms and little or no risk to a one’s life or health, while others cause severe and devastating effects when they bleed. Treatment options range from conservative watching to aggressive surgery, depending on the type, symptoms, and location of the AVM.

What is an arteriovenous malformation (AVM)?

Normally blood flows from the heart through large arteries to all areas of the body. The arteries branch and get smaller until they become a capillary, which is just a single cell thick. The capillary bed is where the blood exchanges oxygen and nutrients with the body tissues and picks up waste. The blood travels from the capillary bed back to the heart through veins. In an AVM, arteries connect directly to veins without a capillary bed in between (Fig. 1). This creates a problem called a high-pressure shunt or fistula. Veins are not able to handle the pressure of the blood coming directly from the arteries. The veins stretch and enlarge as they try to accept the extra blood. The weakened blood vessels can rupture and bleed and are also more likely to develop aneurysms. The surrounding normal tissues may be damaged as the AVM “steals” blood from those areas. There are four types of AVMs: