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.
For the mapping, the client sits in a comfortable chair while the therapist strategically places twenty sensors on the scalp that record the electrical activity of the brain. This electrical activity is processed and compared to an age-normed data base. The processed EEG is then converted into displays of two dimensional function called brain maps. The brain mapping session takes 60 to 90 minutes to record and the processing takes 7 to 10 days to complete.
The information that is derived from the QEEG session can be interpreted by experts as a clinical tool to evaluate brain function. In addition to directing treatment, it is used to evaluate neurofeedback treatment response through tracking changes in maps over the course of training. It can also be used by trained experts to evaluate a client’s response to medication.
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 below illustrates the brain maps color coded Z scores. Normal, or one standard deviation (SD) low or high, is green. Less than normal is blue and too much is yellow, orange, or red. Two standard deviations and above has come to be considered a reflection of pathology.
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.