Understanding QEEG
Quantitative Electroencephalography (QEEG) is the mathematical processing of digitally recorded EEG to highlight specific waveform components, transform the EEG into a format or domain that elucidates relevant information, and associate numerical results with the EEG data for subsequent review or comparison.
The 10-20 System
We utilize the International 10-20 system for electrode placement, ensuring standardized measurement across all 19 cortical sites.
Spectral Analysis Bands
| Band | Frequency | Clinical Correlate |
|---|---|---|
| Delta | 1-4 Hz | Deep sleep, white matter lesions |
| Theta | 4-8 Hz | Drowsiness, memory consolidation |
| Alpha | 8-12 Hz | Relaxed wakefulness, idling state |
| Beta | 12-30 Hz | Active processing, anxiety (high beta) |
Raw EEG traces are converted via Fast Fourier Transform (FFT) into spectral density maps, which are then compared against normative databases to calculate Z-scores.