For example, this might be early in the morning.
With focal (partial) seizures the activity is only happening in some areas of your brain. When an EEG test picks up unusual electrical activity, the doctor will look at where it is happening in the brain. Can an EEG test show what type of seizures I have? So, an EEG that shows unusual brainwave patterns doesn’t always mean that you have epilepsy. These could be caused by other medical conditions, problems with their vision, or brain damage. This information is very helpful for doctors when they are making a diagnosis.Ī small number of people have unusual EEG test results, even though they never have seizures and they don’t have epilepsy. When they have an EEG test, the results can show certain brainwave patterns that doctors recognise. People with some types of epilepsy have unusual electrical activity in their brain even when they are not having a seizure. And it doesn’t exclude you having epilepsy. This doesn’t prove that you don’t have abnormal activity in your brain at other times. So, if your EEG test doesn’t show any unusual activity, it only means that there is no epileptic activity in your brain at the time the test is being done. The rest of the time the brain activity may be entirely normal. Many people with epilepsy only have unusual electrical activity in their brain when they are having a seizure. What information does an EEG test give?Īn EEG test gives information about the electrical activity that is happening in your brain at the time the test is carried out.
You might be asked to take a simple piece of portable recording equipment home with you. You may find it useful to plan how you will get home after the appointment. Some people find the process quite tiring and there is a very small risk you might have a seizure during the test. People with epilepsy have told us that they found it helpful to go with someone to the appointment. Where are EEG tests done?Īn EEG is usually done in hospital in an outpatient clinic. This is because reading an EEG incorrectly is one of the most common reasons for people to be given the wrong diagnosis.
They should always be interpreted by a doctor who specialises in reading EEG results. The results of an EEG can help doctors to make the correct diagnosis and decide on the best treatment. Non-convulsive status epilepticus can change a person’s level of awareness or cause confusion, but might not be recognised as a seizure without an EEG. Sometimes an EEG is done to check whether someone is in non-convulsive status epilepticus. They want to withdraw your epilepsy medicines.You are being considered for epilepsy surgery.They are unsure whether or not your seizures are due to epilepsy.You have epilepsy, and they need to know more about it.Your doctor might ask you to have an EEG (electroencephalogram) test for one of the following reasons: Some of these patterns point to a strong possibility of epilepsy. At different times, your brainwave patterns may be different.Ī highly trained specialist, called a clinical neurophysiologist, can recognise if your EEG test shows a brainwave pattern that is different to most other people. The EEG test can only show your brainwave patterns at the time the test is carried out. The electrical signals look like wavy lines that show your brainwave patterns. They don’t interfere with your brain and they don’t cause you any pain. They only pick up the electrical signals.
The electrodes pick up the electrical signals from your brain and record them on a computer. Hair conditioner can help to remove the glue afterwards. After the electrodes are removed, you may still have a lot of glue in your hair. Electrodes are attached using a special paste glue or paste. The electrodes are connected by wires to an EEG machine. During an EEG test, small sensors, called electrodes, are placed on your scalp. Your brain constantly produces tiny electrical signals. What types of EEG tests are there? What is an EEG test? What does an EEG test do?Īn electroencephalogram (EEG) records activity in the brain.