U. Zwiener et al., Quantitative topographical analysis of EEG during nonstandardized and standardized hyperventilation, J CL NEURPH, 15(6), 1998, pp. 521-528
The aim of this study was to compare the topographical quantitative EEG (qE
EG) changes induced by nonstandardized hyperventilation and those induced b
y standardized hyperventilation (with the end-tidal PCO2 being maintained a
t 2 kPa [15 mm Hg]). We examined 18 healthy volunteers during nonstandardiz
ed and 20 during standardized hyperventilation. During nonstandardized hype
rventilation, the mean spectral power density in this group significantly i
ncreased 1.9 fold within the delta-, 2.2 fold within the theta-, 1.8 fold w
ithin 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 be
tween 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 withi
n the alpha-, and to 2.4 fold within the beta frequency band. The power rat
io decreased significantly. Such a pronounced EEG slowing with delta and th
eta augmentation was never found during nonstandardized hyperventilation. W
e conclude that a consistent slowing of the qEEG in all leads including a c
onstant topographical maximum can only be induced by standardized, sufficie
ntly pronounced hyperventilation.