Before neurofeedback treatment begins, every patient is given a Quantitative Electroencephalogram (QEEG), otherwise known as brain mapping. This process provides an objective assessment of brain health and serves as a road map for neurofeedback treatment. When getting a QEEG, the client sits in a comfortable chair while the therapist strategically places 20 sensors on the scalp that record the electrical activity across the brain. This electrical activity is quantified and compared to an age-normed database. The processed EEG is then converted into displays of two-dimensional function (frequency band x activation level) called brain maps. The information that is derived from the QEEG session can be interpreted by experts and used as a clinical tool to evaluate brain function, and to tailor the treatment program to the specific needs, symptoms, and brain activity of the client.
In addition to directing treatment, it is used to evaluate neurofeedback treatment response through tracking changes in maps over the course of training. Trained experts are also able to assess how a client’s brain responds to various medications.
The brain mapping session takes 60 to 90 minutes to record and the processing takes 7 to 10 days to complete.
Below is an example of one page of a brain map. Look for the nose on each head to orient yourself to the front or anterior part of the brain. Looking at the labels above the heads from left to right in the top row tells the viewer the frequency band of the head maps for that column. The columns from left to right are the delta band, followed by the theta, alpha, beta, and high beta bands.
Each row is a discrete form of analysis. The top two rows are Absolute Power and Relative Power respectively. These categories reflect your brains activation process compared to normal brains. The bottom three rows, Amplitude Asymmetry, Coherence, and Phase Lag measure your brain’s network functioning. Amplitude Asymmetry compares the activation process in one region to that of other brain regions. Coherence measures the amount of information sharing between cortical areas while Phase lag assesses the speed of information sharing within network areas.
The bell curve above illustrates the brain maps corresponding z-scores, differentiated by color. The central 50% line represents the age-normed average to which the patient’s brain map is compared. Normal brain activity falls within one standard deviation (SD) above or below this central line, represented by the color green. Brain activity considered to be less than normal falls within two SDs above or below this line, represented as yellow and blue, respectively. Red, dark blue and even orange colored brain maps are considered to reflect abnormal electrical activity as they fall three SDs away from the normed average. Generally, two SDs and above has come to be considered a reflection of pathology. When this activity is present in a region or network that is associated with the client’s complaints then we may target that region or that area’s cortical network for neurofeedback training.
Orange, Red or dark blue maps are considered to reflect abnormal electrical activity. When this activity is in a region or network that is associated with the client’s complaint then we may target that region or that area’s cortical network for neurofeedback training.