✎ Written by: Dubravka Rebic

The total number of neural connections in the brain is 1, followed by 12 zeros, a number as large as the number of stars in our galaxy. The human brain is indeed the single most complex thing in the known universe.
However, this complexity is not without order. In fact, it can be captured, labeled, and quantified with qEEG brain mapping. Quantitative electroencephalography, or qEEG, is a method that measures electrical activity in the brain, compares these measurements to normative values, and creates a visual topographic map. So just like the countries and continents are represented on a geographic map, with qEEG, areas of the brain are spatially defined, and their functionality is measured so that it can be compared to normative values.
These important measurements can enable you to:
Identify the root cause of certain psychological or physiological symptoms
Create an optimal data-driven therapy plan
Measure your clients' progress with neurofeedback
In this article, we'll explain how qEEG brain mapping works, why it can be an important part of your mental health toolkit, and how it can help you transform your practice.
How Does qEEG Brain Mapping Work?
A qEEG test starts with an electroencephalogram (EEG), which measures brainwave activity through sensors placed on your client's head. These brainwave readings are sent into qEEG software, which interprets and transforms the data.
The performance patterns of a single client are compared to known brain performance markers calculated from a qEEG normative database acquired from thousands of other brains. Z-Scores are based on the EEG signal, the sensor locations, the individual's age, the individual's gender, and whether the eyes are open or closed. With this information, the Z-Score is able to provide values of 0.0 (normal), positive (above normal), and negative (below normal) scores.
For example, the qEEG report could show regions that demonstrate abnormal brainwave activity, as compared to the norm (i.e., other age-matched clients).
On a map, the isocontour lines represent increments of the standardized (Z-score) units. Black dots represent electrode localizations, which include AF7, AF8, F3, FZ, F4, CZ, TP9, TP10, and O1. The voltage is standardized relative to the mean voltage for the normative population in the same age group.
