[The clinical, neurophysiological and differential diagnostic aspects in a study of severe forms of early childhood autism].

Clinical, pathopsychological and neurophysiological studies have been carried out in 85 children with infantile autistic psychosis and in 38 girls with Rett's syndrome. New improved differential diagnostic criteria between these two forms of early childhood autism have been suggested. EEG spectral density values in alpha-1, alpha-2, beta and theta subbands are established to be their neurophysiological markers. Special attention was paid to close relationship between ontogenetic neuromorphogenesis of the brain cortical structures (e.g. physiological lysis of cortical cell populations at the age 8-30 months of the child's life) and the defect severity in the onset of illness at the same age range in patients with the studied forms of early childhood autism. The data obtained are discussed in terms of new approaches to understanding pathogenesis of different forms of early childhood autism.