What is EEG test?

Frequently Asked Questions:

What is EEG used for?

EEG is used for recording brain activity. EEG isn't usually able to record specific events, like seeing or smelling something; instead, it records general activities of the brain. EEG doesn't localize where signals are coming from in the brain like fMRI does (functional MRI).

Understanding the test results of EEG Test

An electroencephalogram (EEG) is a test that records the electrical activity of the brain. It detects and records the time taken for an impulse to travel from one place in the brain to another or records the number of times such an impulse occurs within a certain period. The electrical impulses can be recorded and read by electrodes placed on the scalp. It is a diagnostic procedure used to investigate epilepsy and other neurological disorders, including brain tumors and strokes.

Why do I need EEG?

There are many different reasons why we may need to measure the electrical activity in our brains. Some of them include Clinical treatment and diagnosis of many common and debilitating brain disorders such as epilepsy, autism, Parkinson's disease, chronic pain, and depression, which have been correlated with changes in EEG activity. The ability to detect EEG activity has been combined with real-time feedback, allowing subjects to learn how to control their brain states voluntarily. This technique has been used in a variety of applications, including relaxation training and skill acquisition. EEG signals can be used to detect patterns of electrical activity linked to different thoughts or intentions.

What happens during EEG?

"Electroencephalography (EEG) records electrical activity along the scalp. It measures voltage fluctuations resulting from ionic current within the neurons of the brain." 

In a conventional EEG, electrodes are placed along the scalp to measure this electrical activity using an electroencephalogram machine. The recorded signal is very similar to that of a baby monitor. The signal is transmitted to an electroencephalograph machine, which records the data on paper or a digital screen.

Which is better, EEG or MRI?

Both EEG and MRI are valuable tests that provide unique information about the brain. Each test has its strengths and weaknesses, but neither is better than the other overall.

Can an EEG detect a brain tumor?

It is possible, but not always. A routine EEG does not detect brain tumors as only some types of brain tumors show on an EEG. Many factors such as the size and location of the tumor, how fast it is growing, and individual differences between patients need to be considered before a conclusion can be made.

Can EEG pick up anxiety?

The EEG can pick up on some changes in anxiety, and it is therefore alluded to as an indirect measure of anxiety. The type of research that has been done suggests that there is a relationship between EEG and anxiety. But the results are not clear enough for researchers today to use the EEG as a direct diagnostic tool for measuring anxiety. The studies that have been done are very small, and there's no clear "anxiety marker" in the EEG.

Can an EEG detect past seizures?

In short, yes, with enough data, it is possible. The idea is based on patterns of activity within the brain. If seizures are periodic and regular, every time they happen, there will be a pattern of onset which can be detected should it repeat in an EEG recording. It's simply looking for peaks at the same point in the cycle every time.

How long do you have to be awake before an EEG?

EEGs are done when a patient is awake. One cannot get an accurate EEG when the patient is asleep since the brain waves drop drastically; therefore, the patient needs to stay awake until all measurements (including Fp1, Fp2, C3, C4, etc.) have been finished.

Can I eat before the EEG test?

Yes, you can. The reason behind this is when someone is in a relaxed state when they eat before being hooked up to an EEG machine; it allows the behavior of their brainwaves to be more consistent with what people think is "normal." In other words, if someone were tested while fasting and then again after eating, the results could be extremely different.