Hyperventilation activation on EEG recording in childhood.

In 66 children with no neurologic symptoms, we analyzed EEG slowing quantitatively during standardized hyperventilation (HV) activation [respiration rate (RR) of 30/min, threefold increase of VE, and 4-min duration]. Changes in cerebral blood flow (CBF) and velocity were also monitored in right common carotid artery by Doppler ultrasonic method. Decreases in PCO2 and CBF were the fundamental factors producing EEG slowing during HV. The degree of EEG slowing was greater in younger children and well proportional to age with such standardized HV. The decrease in CBF was much greater in younger children at the beginning of HV and may be related to the significant EEG slowing. EEG slowing was not related to the degree of decrease in CBF. The age difference in EEG response to HV in children and adults may be due to the differences in the decrease in the CBF volume and sensitivity of the CNS to the change in CBF.