Coherence:

Coherence is a measure of the degree of neuroelectric communication (i.e., correlation) between each pair of 19 electrodes across four spectral frequency bands (Delta, Theta, Alpha, and Beta). That is, it is an indication of how well these pairs of areas communicate or function in a similar fashion. Normative standards have been established for each pair and statistical estimates of deviation (i.e., Z scores) from these norms are used as indices of dysregulation in coherence.

Phase:

Phase is a measure of the time (or speed) which is required for neuroelectric signals to travel between each pair of the 19 electrodes. Phase is measured in milliseconds and is presented for each of the four spectral frequency bands (Delta, Theta, Alpha, & Beta). Statistical estimates of deviation (Z scores) from the normative sample are used as indices of phase dysregulation.

Asymmetry:

Asymmetry is a measure of the ratio of electrical power (i.e., balance of power) between each pair of 19 electrodes across four spectral frequency bands (Delta, Theta, Alpha, & Beta). Statistical estimates of deviation (Z scores) from the normative sample are used as indices of dysregulation.

Absolute Power:

When QEEG results are analyzed, the distribution of total power is partitioned into four major frequency bands. Absolute power estimates the amount of neuroelectrical power within each of the four independent frequency bands for all 19 sites.

Relative Power:

When QEEG results are analyzed, proportions of the total amount of power is calculated for four major frequency bands. Relative power estimates the proportion of the total power found in each frequency band range. Again, all 19 sites are evaluated with a given range.