QEEG (Quantitative EEG / Brain Mapping)
What Is It?
Plain-Language Explanation
QEEG, often called brain mapping, records the electrical signals your brain naturally produces using a cap fitted with small sensors. The result is a colour-coded map showing which brain areas are overactive, underactive, or poorly coordinated. The procedure is painless and involves no radiation of any kind.
You sit quietly for about 20–30 minutes while a computer captures your brain waves. The data is then compared against a normative database from thousands of healthy individuals to identify unusual patterns.
Technical Explanation
Quantitative EEG acquires multi-channel electroencephalographic signals using electrode placement based on the international 10-20 system (19–32 active channels). Signals are sampled at ≥256 Hz, bandpass-filtered at 0.5–70 Hz, and submitted to Fast Fourier Transform (FFT) analysis to extract spectral power in the delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–13 Hz), beta (13–30 Hz), and gamma (>30 Hz) bands.
Output comprises two-dimensional topographic brain maps and inter-electrode coherence matrices. Data are z-scored against a normative database to identify frequency-band dysregulation, hemispheric asymmetry, or abnormal coherence patterns that inform subsequent neuromodulation protocol design.
How It Is Used at Our Practice
In our practice, QEEG serves as the initial assessment for mapping brain activity patterns before commencing a neuromodulation programme. The objective findings guide personalised tES or neurofeedback protocols tailored to each patient's individual neurophysiological profile.
The assessment is conducted in a dedicated session; results are reviewed with the patient and family in plain language, accompanied by a printed brain map as a visual reference.
Scientific Evidence
- Thatcher RW et al. 2015, Clin EEG Neurosci — Normative QEEG databases and clinical applications
- Newson JJ & Thiagarajan TC 2019, Front Psychiatry — EEG frequency bands in psychiatric disorders
- Salinsky MC et al. 2020, Epilepsia — Quantitative EEG in neurological practice: a review
- Kropotov JD 2016, Functional Neuromarkers for Psychiatry — Academic Press
Frequently Asked Questions
- Is QEEG painful?
- No. The electrodes attach to the scalp with conductive gel and do not transmit any electrical current to the brain.
- How long until QEEG results are available?
- Quantitative analysis and clinical interpretation are typically completed within 3–5 working days of the recording session.
- Is QEEG the same as a brain MRI?
- No. MRI images brain anatomy; QEEG measures real-time electrical function. They provide complementary information and are not interchangeable.
- Who might benefit from QEEG?
- Patients with cognitive difficulties, post-stroke recovery, attention disorders, or any condition requiring neuromodulation guidance may benefit from QEEG mapping.
Wondering whether this modality is right for your condition?