QEEG (or electroencephalogram) is a recording of brainwave activity. QEEG (Quantitative EEG), popularly known as brain mapping, refers to a comprehensive analysis of brainwave frequency bandwidths that make up the raw EEG. QEEG is recorded the same way as EEG, but the data acquired in the recording are used to create topographic color-coded maps that show electrical activity of the cerebral cortex.
QEEG measures electrical activity of the brain. It provides complex analysis of such brainwave characteristics as symmetry, phase, coherence, amplitude, power and dominant frequency. In fact, subtle disruptions of electrical connectivity and flow in the brain sometimes may be the only or the early signs of a problem.
The primary use of QEEG is to examine patterns of brainwaves and help determine whether a person is an appropriate candidate for Neurofeedback, a treatment that normalizes brainwaves. QEEG does not render a diagnosis, but is designed to help the clinician to make a diagnosis. QEEG is not a substitute for EEG; it is a different process than that carried out by the neurologist when he or she performs an EEG assessment.
QEEG results are presented as Z scores. Z scores represent Standard Deviations (SD) from the norm and span from -3 to +3. Thus a Z score of +2 means that the result is 2 Standard Deviations higher than the norm (+2SD) and exceeds 98% of the age-matched people in the normative sample. A Z score of 0 represents the norm and is color-coded green. Red and blue colors on the maps show brainwave activity that is 3 SDs above or below the norm.