Dwelling time of normal and abnormal brain waves connected with their transformability and sustainability

Abstract

Normality and abnormality of EEG brain waves are associated with the transformability and sustainability time of the five waves types, namely gamma, beta, alpha, theta and delta in the order of their descending frequencies. Normal brain waves are transformable from one type to another with sustainable time in the order of seconds and minutes, while the transformability and sustainability time of abnormal brains may be of the order of months and years for situations where abnormalities are recoverable. Many of the exceptions caused by rhythmic irregularities and/or inappropriate EEG measurements can be identified with their respective wave type and sustainability time. This is done by using the least variance principle (LVP) where abnormalities in frequencies and amplitudes are captured by the variances and their sustaining time.The general notion is that normal waves would have less irregularities and are more predictable by the EEG wave frequencies and phase angles. Normal waves are not only more stable but they have a longer sustainable dwelling time. Waves with abnormally small (abs) and abnormally large (abl) frequencies on the other hand are more persistent on distinct dwelling times that can also affect the waveform stability. Dwelling time intervals of 0–6min. and 4–10min. are selected for abnormal waves in contrast to 0–10min. for normal waves. The average frequencies are decreased from those for gamma waves to delta waves for determining the degree of persistency of dwelling times. Results from LVP show that the time occurrence of abnormally small (abs) and abnormally large (abl) frequencies affects the quality of the waveforms for the same dwelling time.