Center for Health Psychology

Basic qEEG Concepts - Page 2

There are two basic concepts that are employed in the analysis of the qEEG data. The first refers to the type of activity that is occurring at a location in terms of the 5 frequencies. Each frequency can be analyzed according to concepts such as microvolt, relative power, peak frequency and peak amplitude. In general, the important variables for cognitive success are the microvolt and relative power measures. The delta and theta frequencies are generally negatively related to cognitive abilities and the beta variables are positively related. There is a subgroup of ADD children who have excessive amounts of theta in the eyes closed condition.

The second important concept concerns how the different locations communicate with each other. This concept employs the variables of coherence and phase to express communication variations within a frequency. These variables are particular important for cognitive success in adult individuals. The following figure visually presents this concept. We employ a flashlight concept to express coherence relationships. In this concept a particular location is assumed to be the origin of a flashlight which sends a “beam” out to the other locations. When the “beam” arrives at the location, we can calculate a numeric value and compare that subject to the normative database. We will explore this concept further in the specific example section.

A & B have high levels of coherence and phase. B & C do not. We want to see normal levels of beta activity and good connection patterns.

Intervention Models

There have been three general intervention approaches in this field. The first, called a standard qEEG intervention places the sensors over the top central portion of the head and the software is programmed to decrease theta microvolt levels and increase beta microvolt levels. The second approach, called eyes closed database approach, analyzes the subject’s qEEG values under an eyes closed condition and compares his values to an appropriate normative database. The third, called an activation database approach, requires the subject to engage in cognitive challenges and examines the subject’s response (in comparison to the activation database) on the variables that are critical to success at the task. In our opinion, it is this last approach which offers the most compelling logic of approach and documented evidence of effectiveness. We will examine some of this evidence on this website.