It is a “window” into your brain and an objective assessment of neural and mental capabilities.

EEG is a fast, non-invasive, painless and precise measure of brain functional activity. The intimate, dynamic structure of this activity is information-rich about the underlying cellular and intercellular processing, brain physiological, cognitive, and mental functions and resources, brain states and conditions. Thus, EEG reflects a functional brain state.

Digital EEG is the digitally recorded electrical activity generated by the brain. In general, EEG is obtained using electrodes placed on the scalp according to the International 10-20 System with a conductive gel (see Digital EEG Registration Procedure). In the brain, there are millions of neurons, each of which generates small electric voltage fields. The aggregate of these electric voltage fields creates an electrical reading which electrodes on the scalp are able to detect and record.

The core principle of quantitative EEG (qEEG) lies in the "precise and objective quantification" of electrophysiological brain activity by computerized analytic and statistical techniques. It permits extracting more precise information from the brain electrical activity than when using the conventional, simple unaided visual inspection of EEG signal. qEEG evaluates the manner in which a particular person’s brain physiological, cognitive and mental functions are organized and how the brain uses its strength and resources to cope with stress or disease and compensate for it.

Numerous studies have proved the stability and specificity of certain qEEG parameters. These parameters were being studied quantitatively in large samples of healthy functioning individuals across different nations and wide age ranges. These studies confirmed the high specificity of normative distributions of qEEG parameters within different EEG frequencies (delta, theta, alpha, and beta bands). Positive findings that differ from the normative values in healthy, normally functioning individuals have been shown repeatedly to be within the chance levels, with very high test-retest reliability. Normative data has been extended to cover the age range from 1 to 95 years for each EEG electrode in the standardized International 10-20 System and includes many parameters of qEEG. The independence of the normative qEEG descriptors from cultural and ethnic factors enables objective assessment of the brain functional state and integrity in individuals of any age, origin, or background.

Scientific literature on qEEG shows that as many as 89% of EEGs in neurological and as many as 68% of EEGs in psychiatric patients provide evidence of pathophysiology, and these results have additional utility beyond simply ruling out “organic brain lesions”. Such EEG studies may also aid in differential diagnosis, treatment selection, and evaluation. For example, several longitudinal studies have shown that initial qEEG profiles may distinguish among patients with the same DSM diagnosis who will respond preferentially to different medications or who will display different evolution of illness. In the Position paper of the American Medical EEG Association on qEEG, it is concluded that qEEG is of high clinical value now in dementia, mood disorders, mild head injury, learning disabilities and attention disorders, and schizophrenia and developments. Additionally, qEEG “scientific,” “technical”, and “other specialized” knowledge meets the standards of the Supreme Court rulings, thereby supporting qEEG as an admissible and clinically valid method in the evaluation of the nature and severity of neuropsychiatric disorders.