[Development of the electroencephalogram in children--comparison of visual and automatic evaluation].

EEGs were recorded of 399 normal children, age 6 months to 5 years, in the Munich Pediatric Longitudinal Study. In all age groups bipolar EEG derivations were recorded with eyes open; in 259 children (age 3, 4 and 5 years) also with closed eyes. The visual evaluation--using a computer adapted evaluation sheet--showed a dominant activity of 5.5 Hz in 6 months old children, of 9 Hz in 5 years old children (eyes open). The mean amplitudes of the dominant activity decreased by 10 microV during this time. With eyes closed the dominant activity in the parieto-occipital area showed an increase from 7.7 to 8.5 Hz. The amplitude of 40-50 microV in the parieto-occipital areas was higher than in the frontal and temporal areas (25-30 microV). Examination with spectral analysis showed a reduction of the relative power in the delta range from 77 to 69% with a simultaneous increase in the alpha range from 3 to 10%. The peak frequencies showed an age dependent development corresponding to the visual analysis. Under the condition eyes open, the mean values of peak frequencies showed an increase from 8.6 to 9.5 Hz in the fronto-central areas and from 8.5 to 9.4 Hz in the occipital areas. With eyes closed the increase of peak frequencies reached up to 0.6 Hz for the age of 4 to 5 years. Age classification is more exact with spectral parameters. Compared to visual parameters, up to 29% more children were classified in the correct age-groups by spectral parameters. As expected the recognition rates decreased in older children.