What Does A QEEG Tell You About Your Brain?
A QEEG will give you information on a number of aspects of your brain wave functioning:
 

1) Absolute and relative power are indications of the balance of activity in each brain wave band (beta, alpha, theta and delta) as compared to the other bands. When there is too much or too little activity in one or more of the brain wave bands, the brain is not working efficiently. For example, many people with ADHD often have too much theta activity compared to their beta activity when their eyes are open. In practical terms, this means that their brains are producing an excess of waves associated with internal focus and drowsiness (theta) and not enough of the waves associated with external focus and alertness (beta).

2) Coherence is a measure of how much activity is shared between different parts of your brain. High coherence between two locations means that they are working too closely together. Low coherence means that the two sites are not sharing enough electrical activity. Coherence deviations are often seen in persons with traumatic brain injury, learning disabilities and autistic spectrum disorders.

3) Phase is a measure of the speed with which signals travel through your brain. The brain’s ability to process information is impaired if electrical signals are moving too slowly or too quickly from one part of the brain to another. You can think of phase as being similar to trying to hit a baseball. A ball that comes at you at medium speed is easy to hit. If the pitcher throws a fastball, the ball may have passed you before your bat can touch it. A slow, high pitch can also be hard to hit.

Digitally recorded EEG data can also be used to perform a discriminant analysis, which is the use of a mathematical formula to determine of a person’s brain waves have the characteristics that are associated with certain medical and psychiatric disorders. Discriminant analyses that look for EEG signs of traumatic brain injury, learning disabilities, depression and ADHD are frequently used.

How Is A QEEG Performed?
A QEEG is performed while you are awake and sitting in a comfortable chair. The first 30 to 45 minutes of the QEEG session is devoted to placement of the EEG sensors on your head. Until relatively recently, each of the 19 scalp electrodes had to be individually glued on. However, the development of an electrode cap has made the process much easier. The cap, which looks like a mesh fabric shower cap, has the electrodes implanted in it. It is placed on your head and conductive paste is squirted into the electrodes to assure that they make a good connection with your scalp. Two other electrodes, which look like clip-on earrings, are attached to your ears. Most people find that the cap and ear clip electrodes cause very little discomfort. 

Once the cap and ear electrodes are in place and their connections have been checked, ten minutes of eyes closed and eyes open brain wave activity is recorded. You will be asked to sit with your eyes closed and remain as still as possible and then sit with your eyes fixed on a particular spot to help reduce eye movement. The brain functions differently with the eyes open versus eyes closed, so seeing how your brain is working in both conditions is important. In some instances another ten minutes of brain wave activity is recorded during performance of a task, such as reading or doing mathematics. 

Does your child have a hard time sitting still for more than a few minutes? This is a problem that is frequently encountered when doing a QEEG with ADHD children. There are a number of ways to deal with it, such as taking frequent breaks or having the child sit on your lap. It is recommended that you bring along a DVD, book or portable video game to help keep your child entertained while the sensor cap is being attached.

Click here to download sample QEEG maps!