title: Quantitative topographical analysis of EEG during nonstandardized and standardized hyperventilation.
abstract: The aim of this study was to compare the topographical quantitative EEG (qEEG) changes induced by nonstandardized hyperventilation and those induced by standardized hyperventilation (with the end-tidal PCO2 being maintained at 2 kPa [15 mm Hg]). We examined 18 healthy volunteers during nonstandardized and 20 during standardized hyperventilation. During nonstandardized hyperventilation, the mean spectral power density in this group significantly increased 1.9 fold within the delta-, 2.2 fold within the theta-, 1.8 fold within the alpha-, and 1.9 fold within the beta-frequency band. There was no significant change of the power ratio and was no topographic difference between 4 frequency bands investigated. During standardized hyperventilation, the mean spectral power density in the group significantly increased to 12.9 fold within the delta-, to 7.6 fold within the theta-, to 1.4 fold within the alpha-, and to 2.4 fold within the beta frequency band. The power ratio decreased significantly. Such a pronounced EEG slowing with delta and theta augmentation was never found during nonstandardized hyperventilation. We conclude that a consistent slowing of the qEEG in all leads including a constant topographical maximum can only be induced by standardized, sufficiently pronounced hyperventilation.
authors.affiliation: Institut für Pathophysiologie, Klinikum der Friedrich-Schiller-Universität, Jena, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Zwiener
authors.forename: S
authors.initials: S
authors.lastname: Löbel
authors.forename: M
authors.initials: M
authors.lastname: Rother
authors.forename: M
authors.initials: M
authors.lastname: Funke
mesh_terms: D000328:Adult; D001931:Brain Mapping; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D006985:Hyperventilation / Q000175:diagnosis*; D008297:Male; D009778:Occipital Lobe / Q000503:physiopathology; D010296:Parietal Lobe / Q000503:physiopathology; D013702:Temporal Lobe / Q000503:physiopathology; D013997:Time Factors