Introduction to the QEEG Assessment

A quantitative EEG (QEEG) is an extensive assessment of the brain’s (naturally occurring) electrical activity (EEG). This assessment helps us to evaluate (maladaptive) brain function and determine areas of the brain that would benefit most from neurofeedback training, thereby revealing the path to improvement.


Numerous electrodes are attached to the scalp surface at strategic points to measure the underlying brainwave patterns in different parts of the brain. It is a safe, painless and non-invasive procedure. It is also a very reliable and technically sophisticated methodology.                  

EEG cap fitting

Research has found that QEEG assessments equal or surpass other frequently used clinical procedures, including CAT scans.   For further information about the QEEG procedure please see The QEEG Assessment Procedure below*.

A client's QEEG recording is relayed to a computer where it can be processed and analysed using complex mathematical and statistical methods. Brain activity is then compared to a normative database to determine which areas of the brain are functioning well and which areas may be functioning below the optimum. Using specialised equipment and computer software, dysregulated or abnormal brain wave patterns - such as over-activation or under-activation of different brain frequencies at specific brain regions - can be identified and quantified. The generated “maps” of maladaptive brain activity will be evaluated by our PeakMind specialist to determine how best to re-train the brain to correct dysregulation/ abnormalities in brain activity, for optimal brain functioning and well-being. This information is used to create a personalised treatment plan specific to the individual.

Understanding the QEEG "Brain Maps"

“Brain Maps” are a diagnostic tool presented as visual displays that reveal abnormalities (i.e. the extent of variation from the norm) for all brain frequencies at numerous brain sites. Our specialist analyser and reviewer of QEEGs and Brain Maps will look at a number of important areas to identify and quantify maladaptive brain activity.This includes the amplitude or size of the brainwaves. We are able to examine brain activity in minute detail (e.g. 1Hz bins - very small increments in frequency) to target the exact nature of brain malfunctioning. (This allows for more effective and efficient neurofeedback training).

We employ Thatchers Lifespan Normative EEG database, a recognized and validated reference database called that entails normative data from hundreds of healthy subjects from 2 years to 85 years of age and provides normed quantitative EEG measures.             

Normal distribution

Numerous peer reviewed publications exists based on this QEEG normative database and it is well recognized and accepted within the scientific community. These Lifespan EEG data in the database are normally distributed with a gaussian shaped distribution as shown in the bell-shaped curve in the figure above which means that we can compare a clients EEG data with gender and agematched EEG data from healthy subjects in the database. Mathematically and statistically, we can express how many "z-scores" a clients EEG deviate from normed data. The green colour in the figure above signifies that the persons particular EEG measurement falls within the mean of that age group (z=0).  Red and blue colours indicate deviations from normal (excess or too little of a particular type of EEG activity compared to gender and agematched EEG data from healthy subjects). Any deviation from normal brainwave activity can have a huge impact on day-to-day functioning and behaviour. For instance, under- or over-activation of brain activity can be experienced as: concentration or attention deficits, an inability to cope with stress, episodes of depression, impaired focus, seizures, deterioration in memory, and many more symptoms. The good news is that with neurofeedback training*, you can take charge by re-training (normalising) the brain to function normally, and so improve life. Corrected and regulated brain activity can reduce or eliminate negative symptoms and also result in: improved creativity, peak performance, efficient learning, etc.

Brainmap example from client with ADD

The statistical significance and meaning of the colour coded z-scores are used when interpreting brainmaps, in conjunction with knowledge of neuropsychological functioning and subjective states/difficulties.

An example can be seen below from a client with ADD and concentration difficulties. The illustration below shows the obvious visual differences in brainwave amplitude or size compared with normal brain activity.

The brain maps to the right further highlight abnormalities in brain function; the red colour indicates areas of severe over activity within a specific slowwave frequency band called delta. The client performed trained to suppress slowwave activity in the left frontal area of the brain, an area which regulates several executive cognitive functions. An early brainmap performed after only 12 sessions showed significant reductions in the amount of slowwave activity in the left frontal area concomittant with subjective improvements. The training electrode was subsequently moved to another area on the scalp to downtrain activity there.


qeeg pre and post 12 sessions only

Read more about practical matters here.