The EEG is a painless investigation that tells doctors about the activity of the brain. During an EEG, electrodes are placed on the scalp using a special glue or sticky tape. These electrodes are connected to the EEG machine that records – on paper or computer – the electrical signals from the brain. It is important to remember that an EEG only shows what is happening in the brain at the time it is being carried out. An abnormal EEG does not necessarily mean that someone has epilepsy and a normal EEG does not necessarily mean that someone does not have epilepsy. However, it is a common test in investigating epilepsy and can be very helpful to doctors.
This scan is a type of X-ray that looks at the structure of the brain. It does not show if someone has epilepsy but it may show if there is an abnormality that could cause epilepsy. It will not be appropriate or necessary for everyone to have a CT scan.
Like the CT scan, the MRI can show if there is a structural cause for a person’s epilepsy. However, the MRI is a more powerful machine, so it may pick up abnormalities that the CT scanner may not detect. The MRI uses radio waves and a magnetic field, rather than X-rays.