EEG BANDS AND SINGLE-FREQUENCY ACTIVITY

For the most part, work done with EEG feedback equipment today directs its interventions to maximizing or minimizing the activity of a number of broadly-defined bands, such as theta, alpha, and beta. The exception to this work is that done by Tansey in 1984 as he directed his interventions toward narrowly-defined 1-Hz-wide frequencies such as 5, 7, 10, 14, 16, or 20 Hz. Tansey has pointed out the fallacy of directing therapeutic efforts toward wide (generally 4-Hz-wide) bands when he correctly asserts that a frequency drop in one part of a band can cancel a frequency rise within the same band, allowing the activity of the entire band to give the impression that no change is taking place. Further, when Tansey examines subjective correlates of individual frequency activity, he found intersubjective consistencies from one frequency to another, another reason for attending to narrower electrical units than the broadly- defined frequency ranges. For example, he found visualizing to be a typically correlated with 7 Hz activity across subjects.