title: Covariation of spectral and nonlinear EEG measures with alpha biofeedback.
abstract: This study investigated how different spectral and nonlinear EEG measures covaried with alpha power during auditory alpha biofeedback training, performed by 13 healthy subjects. We found a significant positive correlation of alpha power with the largest Lyapunov-exponent, pointing to an increased dynamical instability of the EEG accompanying alpha enhancement. Alpha power amplification, moreover, was significantly correlated with a decrease of spectral entropy within the alpha range. This outcome reflects a sharpening of the alpha peak during biofeedback training. The fact that the sharpening effect clearly preceded the increase of alpha amplitude could be exploited in future biofeedback settings.
authors.affiliation: Department of Epileptology, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany. juergen.fell@ukb.uni-bonn.de
authors.forename: Jürgen
authors.initials: J
authors.lastname: Fell
authors.forename: Hakim
authors.initials: H
authors.lastname: Elfadil
authors.forename: Peter
authors.initials: P
authors.lastname: Klaver
authors.forename: Joachim
authors.initials: J
authors.lastname: Röschke
authors.forename: Christian E
authors.initials: CE
authors.lastname: Elger
authors.forename: Guillén
authors.initials: G
authors.lastname: Fernández
mesh_terms: D000328:Adult; D000513:Alpha Rhythm; D001676:Biofeedback, Psychology / Q000502:physiology*; D001921:Brain / Q000502:physiology; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results