back to neurological tests

ELECTROENCEPHALOGRAPHY (EEG)

Sample of the waveforms  recorded during an EEG

Definition

Electroencephalography measures the electrical activity of the brain derived from leads (electrodes) on the scalp.

What is it used for?

EEG is used primarily in the diagnosis and monitoring of seizures and epilepsy. It is also useful in other circumstances including sleeping disorders, encephalitis (inflammation of the brain), some metabolic or chemical disturbances of the brain and in recognizing large structural abnormalities such as tumors.

Preparation

There is usually no preparation needed and the test itself is painless. 

The electrodes that are placed on the scalp are often glued on with a paste which can be difficult to remove and causes the hair to be messy. Taking a cap or hat with you to cover your hair is a good idea.

Sometimes the study is done in a 'sleep deprived' or over tired state. This increases the sensitivity of the EEG in picking up seizure activity. In these cases you will need to stay up all night without the benefit of any stimulants such as coffee and have the test done first thing in the morning.

R. O'Brien MD

Where are they done?

There are 20 EEG laboratories in the province. All but one of these are in hospitals. 

They are (alphabetically):