q EEG – Quantitative Electroencephalography

Quantitative Electroencephalography (q EEG) is a diagnostic tool that provides a computerized and mathematical analysis of the electrical activity of the brain and is recorded by the EEG.  The different brain wave patterns are associated with and reveal important information about the functioning of the brain such as stress and  anxiety, impulsivity, cognitive flexibility, depression, emotional dysregulation, panic disorder, OCD, learning disorders such as ADD/ADHD, and generally correlate with other psychometric test results

The EEG signals are converted into numerical data.
The frequency analyses identify the different frequency bands (e.g., delta, theta, alpha, beta, power.)

q EEG provides a more objective and precise assessment of brain function compared to traditional EEG and measures coherence or connectivity and phase lag. Coherence means the connectedness or consistency between two sites on the brain. The waves are characterized by the same frequency or orderliness. In other words, communication, and coordination between two sites. Coherence focuses on hyper or hypo connectivity between two sites or overly connected or poorly connected.

Phase measures time delay in activity between two sites. The significant time delay may refer to pathology i.e. earlier brain damage. Phase measures the speed of information traveling between two sites in the brain.

The q EEG allows for:

1. Brain mapping: Visual representation of brain activity.
2. Neurofeedback training: Guided training to self-regulate brain function.
3. Clinical applications: Diagnosis, treatment planning, and monitoring of neurological and psychiatric conditions (e.g., ADHD, autism, depression, anxiety and other deficits).

How the electrical data is collected:

From the scalp to the computer screen

• The Different frequencies are recorded on the scalp, sent to the amplifier, and recorded on the computer.
• Converting the traces or frequency bands (delta, theta, alpha, beta, gamma) into the worldwide database will give us detailed information regarding the functioning of the brain.
• The q EEG further measures the power of each frequency band, connectivity or coherence of the brain, and the brain’s functional speed or phase.

Figure  from BFSA website 

The q EEG can be compared to observing light through a prism. The detail is accentuated which cannot be seen with the naked eye on a routine EEG recording and provides information regarding brain functioning and cognition, as compared to a normative or reference database (Thatcher Neuro-Guide is used in this practice) 

The purpose of the q EEG is to suggest treatment montages or protocols. The q EEG is a neuropsychological instrument that validates brain behaviour and is not performed for diagnostic purposes. However, results may be supportive of or correlate with, pre-existing diagnoses or symptoms.