QEEG Assessment   Quantitative Electroencephalography

Electroencephalography (EEG) is the measurement of electrical patterns at the surface of the scalp which reflect cortical activity, and are commonly referred to as “brainwaves”. ‘Quantitative’ EEG (QEEG) is the analysis of the digitized EEG averaged over a time period, and in lay terms this is often called “Brain Mapping”. The QEEG is an extension of the visual raw EEG analysis which assists and increases our understanding of the EEG and brain function

In practice, a QEEG involves placing a 19 channel electrode “cap” over the client’s head which captures the EEG recording and sends it to a computer. Once the cap is fitted and the signal is clear, a 10 minute ‘Eyes Open’ condition, followed by a 10 minute ‘Eyes Closed’ condition is recorded. This multi-channel EEG data is processed with various algorithms for example, “Wavelet” analysis enables the clinician to see amplitudes of specific frequency bandwidths. The digital data is statistically analysed, comparing values with “normative” database reference values. The processed EEG is commonly converted into colour maps of brain functioning called topographic “Brain” maps.

The EEG and the derived QEEG information can be interpreted and used as a clinical tool to evaluate brain function, and to track its changes due to various interventions such as Neurofeedback therapy or medication.

Processing Speed Analysis

Quantitative Electroencephalography (QEEG) processing techniques and the use of modern analytic software to process the EEG/ QEEG, also gives us the ability to view the dynamic changes taking place throughout the brain during cognitive processing tasks. This novel approach can be used to assist us in determining which areas of the brain are well engaged and processing information efficiently, by comparing the Evoked Potentials (event related potentials) of the client to a normative database.

Evoked Potential studies are based on a similar principle as the QEEG studies except, in this case, we challenge the brain to respond to specific environmental challenges. For example, we may ask the brain to detect differences between sounds, respond to mild stimulation of the hands or feet, or watch the brain as it solves problems. These tests help evaluate the integrity of systems allowing the clinicians to determine how well the brain performs basic functions. For example, aberrant response to the auditory processing test will lead the clinician to focus on this system first.

The use of advanced techniques such as Independent Component Analysis (ICA) and neuro-imaging techniques such as Low Resolution Electromagnetic Tomography (LORETA), can map the actual sources of the cortical rhythms. These advanced approaches are changing our understanding of the dynamics and function of the human brain.

At the Listen And Learn Centre a QEEG assessment is used to assist in the diagnosis of disorders and assist in establishment of intervention protocols.

The Listen And Learn Centre is one of a handful of clinics in Melbourne that has QEEG Assessment tools available to test brain function.