Electroencephalograms (EEGs) of 110 pupils (aged 6.5-19.5 years; 48 healthy subjects, 51 with cerebral palsy, 11 with acquired cerebral defect) were acquired. The stable age dependences of averaged parameters of k (.) f(-beta) EEG spectra model, deviations from the model, and normalized ranges of detrended EEGs were found. These dependences were observed in both healthy subjects and patients, in males and females, in the cases of congenital and acquired pathology. This regularity reflects the process of cerebral maturation and developmental change of structure types of the EEG process, and it is inherent to normal as well as to abnormal brain development.