Clinical and electroencephalographic studies were performed to clarify the pathophysiology of the refracted type infantile autism. Fifty children with infantile autism were classified into two groups ; group I was consisted of twenty-eight children, aged 1 year and 10 months to 10 years, who had developed infantile autism below 2 years and 6 months of age, and group II was consisted of twenty-two children with refracted type infantile autism, aged 2 years 1 month to 8 years and 7 months.
Investigations of clinical & E E G findings revealed fewer evidences which suggested the organic brain damage in group II than group I. Many children in group II had a proximate cause at the onset of infantile autism which was thought as psychotic trauma to them. In this group disappearance of speech and appearance of autistic behavior were advanced simultaneously. The prognosis about speech was poorer in group II than in group I. There was a correlation between the prognosis of refracted type infantile autism and the background activity of E E G. These findings suggested that the refracted type infantile autism was not a disorder o speech and perception caused by organic brain damage but a psychic reaction following psychotic trauma.