The latent state-trait structure of resting EEG asymmetry: replication and extension.

Recent research on brain asymmetry suggested that resting electroencephalographic (EEG) asymmetry represents a superimposition of a trait-like asymmetry with state-dependent fluctuations. The present study tested this hypothesis and additionally examined individual differences in state changes. A 61-channel EEG was collected from 59 participants in a resting state on three occasions of measurement. An analysis of latent state-trait models suggested that between 40% and 50% of the variance of anterior asymmetry measures was due to individual differences on a latent trait and approximately the same portion of the variance was due to occasion-specific fluctuations. A further analysis of true intraindividual change models indicated that there were large individual differences in intraindividual change over time. These data replicate previous findings and substantiate that resting asymmetry has trait and state properties.