These results are from 300 seconds of linked ear EEG data, note the dominant slower alpha peak frontally…. And the raw coherence values of that linked ear data. The raw EEG file sample is also included, so you can see the waveforms these values are being drawn from.

Linked Ears

Raw Coherence Values of Linked Ear Data

Raw EEG

The same exact 300 seconds of EEG data, reprocessed now with the weighted average montage.  Note the difference in spectra, and waveform!!!  The temporal slower alpha is now seen as the source of that slower alpha content.

The alpha hypercoherence in the EEG is easily seen in this data, but not in the linked ears.

This shows that you need to find the EEG montage that shows the actual EEG data for your case first, and THEN calculate coherence.

Weighted Average Spectra

Weighted Average Waveform

Weighted Average Raw

The images below show the Spectral plot, coherence plot and raw EEGs. Just like the other montages did. The Cz coherences are so inflated with field effects they are at 0.8 across the full spectrum at some sites, obviously artifactually high.

Spectral Plot

Coherence Plot

Raw EEG

Technical Issues in qEEG Power point Presentation

Continue Reading to see parts 2 and 3.

Part 2 Discusses Z-Scores and Standard Deviations