EEG - Electroencephalograph

An electroencephalogram is a recording of the electrical activity in the brain. It is a noninvasive way to test brain activity. It may be used to diagnose brain and sleep disorders. (Read about "The Brain" "Sleep") The Epilepsy Foundation (EF) calls the electroencephalogram one of the most important tools in diagnosing epilepsy and seizures. (Read about "Epilepsy" "Seizures") EEGs can be used in the diagnosis of an encephalopathy (Read about "Encephalopathy"), which is any disease that alters brain function. For example, EEG can be useful in the diagnosis and treatment of diseases such as Parkinson's disease and cerebral palsy. (Read about "Parkinson's Disease" "Cerebral Palsy") An EEG can also be used on patients in a coma or what is called stupor, which is a slowness to respond to stimuli. An EEG can also be used to help confirm encephalitis. (Read about "Encephalitis & Meningitis")

An EEG is done by placing electrodes on the scalp of the patient. Those electrodes record the electrical impulses in the brain and send them to a special machine. The impulses are recorded on a strip of paper or put into a computer where they can be studied by the healthcare provider.

EF says a patient will be asked to close their eyes for a while, and then the recording will continue after they are asked to open their eyes. Flashing lights may be used to see if the patient is what is called "photosensitive." That means they may be susceptible to having a seizure from flashing lights. They may also be asked to hyperventilate. EF says hyperventilation can result in seizures in some people.

EEG's are also performed on people while they are asleep. Unusual brain electrical patterns may show up while the patient is asleep. In addition to EEGs, there are other procedures that can be used in the diagnosis of brain related conditions, including CT scans, MRI and PET scans. (Read about "CT Scan - Computerized Tomography" "MRI - Magnetic Resonance Imaging" "PET - Positron Emission Tomography")