Raw EEG sampleQuantitative Electroencephalography

There are only a few reliable ways of assessing the activity of the human brain, nearly all of which require expensive equipment and are restricted to scientific laboratories. Quantitative electroencephalography, or QEEG, is an exception. QEEG is based on the electroencephalogram (EEG), the "brain waves" with which we're all familiar. EEG measures the electrical fields generated by the brain, detectable from electrodes placed on the scalp. For QEEG, the electrical signal is measuredQEEG traces from 19 locations distributed across the scalp. Then it's digitized, amplified, processed mathematically, and compared to what would be typical of a healthy person of the same age. The result is a picture of where, and in what way, the brain is having difficulty regulating itself. Combined with knowledge of the brain's different networks and their functions, it becomes a powerful tool.

Choratech uses state-of-the-art recording equipment and the industry-leading normative database to process and interpret EEG data. With these data we can identify sources of electrical activity deep inside the brain that help to account for symptoms ranging from attention problems, to learning disabilities, to anxiety and depression.

QEEG Head Maps

QEEG is able to confirm the results of diagnoses that are made in other ways, such as by checklists of self-reported symptoms. For example, there are characteristic EEG patterns that correspond to the symptoms of ADHD, learning disabilities, depression, and anxiety. In this way, QEEG adds a level of reliability and objectivity that's not possible using other forms of assessment, especially in the mental health field where diagnosis typically depends completely on self-reported symptoms.

QEEG can also help to guide intervention. At Choratech our main use of QEEG is to guide our use of neurofeedback. Neurofeedback is described in detail on this page, but briefly, it's a form of behavioral training that directly modifies the EEG by giving the brain access to moment-to-moment information about what it's doing, and rewarding it when it moves in the direction of better regulation. Using QEEG, neurofeedback becomes a highly personalized intervention that directly targets the specific brain structures and networks that are having difficulty regulating themselves.

About EEG

EEG frequencies used in QEEG and neurofeedback include Delta (1-4 Hz), Theta (4-8 Hz), Alpha (8-12 Hz), Beta (12-30 Hz), and Gamma (35-45 Hz). Each of these frequencies is associated with its own set of functions. There are slower and faster components in the EEG, but their function is less clearly understood, and they're difficult to measure accurately.