Etiological factors in cerebral palsy: an historical review.

The etiological factors in 1503 patients with cerebral palsy seen since 1947 are listed. Prematurity was the most prominent factor, being present in 27.8 per cent of cases. 38.5 per cent of the causes were prenatal in origin, 46.3 per cent natal, and 15.2 per cent postnatal. Since 1947, the number of patients seen rose to a maximum in the 1950s and has fallen since. A steadily increasing percentage of the patient population has been children with spasticity, especially paraplegia and quadriplegia. Although small, the atonic group has shown a marked increase, from 0.8 per cent in the 1950s to 3.4 per cent in the 1970s. There has been a dramatic decrease in the incidence of athetosis, from 38 per cent to about 3 per cent, and a slight decrease in the rigidities. The incidence of some of the etiological factors has increased, such as hydrocephalus, prematurity, trauma and multiple birth. There has been a striking decrease in the incidence of erythroblastosis as a factor, which dropped to nil in the 1970s. There have been lesser decreases in encephalitis, dystocia and idiopathic factors.