The statistical multi-stage method is applied to a recorded EEG signal, decomposing it into a number of key components (EEG oscillations, their relations and dominance; wave shapes; distribution of EEG oscillations, their amplitude, power and dominant frequency; interhemispheric and anterior-posterior asymmetry; focuses of pathological activity; paroxysmal activity) that characterize the signal. Based on these components and the principles of information theory, the typization of a qEEG signal is obtained and the degree of deviation from the optimal norm is estimated.

A comprehensive quantitative EEG (qEEG) analysis compares the electrical activity generated by your brain with an optimal reference of healthy individuals of your age and gender (normative reference) and a specific neuropathology group (pathologic reference) when needed. This can help identify optimal, suboptimal and abnormal functioning in the brain, the degree of these abnormalities, and also shed light on the nature of those abnormalities.

In this way, the probability that an individual belongs to a specific category or a subtype within a category is evaluated.

The optimal range of qEEG characteristics represents certain ideal characteristics displayed by a majority of subjects in the same age group, without current or past neurologic or mental complaints, without other illnesses or traumas (physical or psychological) that might be associated with brain dysfunction, without a history of substance abuse, and without a family history of neurologic and psychiatric diseases.

Deviation from the optimal range does not necessarily reflect abnormality or a pathological process. Deviation means that the brain functions outside the optimal range, thus spending more energy and resources to achieve needed results/aims. In other words, the brain works less efficiently.

If compensatory mechanisms of the brain are intact, then the qEEG characteristics’ deviation is pathogenically insignificant. However, the pathogenic significance of qEEG deviations from the optimal range increases when compensatory mechanisms of the brain are exhausted. This is usually associated with strong and very strong deviations from the optimal level.

Interpretation of the qEEG includes information regarding qEEG data based on published scientific research and careful consideration of other signs and symptoms that an individual presents with.

Advanced analysis of functional brain activity measured by electroencephalogram (EEG) provides a quick screening for the brain's functional state, estimates its predispositions, and neural and mental capabilities.