Abstract
I identifed forty-three patients with severe retardation aged 6-14 years in a defined community. More than half of the patients (23/43) had spastic tetraplegia and 9 had spastic diplegia. Only one case showed abnormal increase of muscle tone of dyskinetic type. The period when they had got underlying causes of their handicaps was as follows: congenital (acquired intrauterine, including intractable cases) 25, perinatal 6, and after the neonatal period 12. An increased proportion of congenital cases and a decreased proportion of perinatal cases are noted when the data were compared with previous reports. About a half of the total cases could be considered to be caused by preventable diseases such as perinatal anoxia, purulent meningitis, or intracranial hemorrhage due to vitamin K deficiency
