Experimental and clinical studies of neonatal eeg mapping--methodical prerequisites and data interpretation

To investigate whether the sampling theorem was fulfilled up to now in experimental and clinical EEG-mapping of neonates and to determine the "smearing effect" of EEG transmission by the leading media up to the skin, EEG-maps from 5 slightly anaesthetized term newborn piglets and 8 healthy human newborns were calculated. A spatial sampling rate of 1-2 cycles per cm is necessary for a sufficient reproduction of surface EEG topology in newborn piglets showing activity maxima within motor projection zones. In human neonates, 8-channel mapping gave insufficient results, whereas state and EEG pattern related 16-channel maps provided sufficiently constant, but not complete pattern. Simultaneous maps from epidural and epiossal, and epiossal, and surface recordings in newborn piglets showed only small "smearing" effects. We conclude, the more topical interpretation chances exist, like in neonates with smaller "smearing" effects of transmission media, the more complete uptake of original data for mapping is necessary. Up to now, it is done seldomly.