Fig. 2
From: The case for using digital EEG analysis in clinical sleep medicine
Three-second EEG tracings (C3/A2) showing a range of patterns, their bin numbers and probability (Pr.) of the pattern occurring during periods scored awake or as arousals by a consensus of expert scorers. The four digits in the bin number represent the normalized powers in (from left to right) delta, theta, alpha/sigma and beta frequency ranges. Note that a variety of patterns can share the same probability. The probability is determined by the relation of the 4 powers to each other. It increases as alpha and beta powers (last two digits) increase and as theta power (second digit) decreases. High delta power may increase or decrease the probability depending on the other powers (5)