Intellectual sequelae of primary non-obstructive hydrocephalus in infancy: analysis of 50 cases.

In 50 cases of primary non-obstructive non-progressive hydrocephalus in infancy, possibilities of predicting later intelligence were investigated. The mean IQ was 80 +/- 24; in 50% of the cases IQ was normal, in 22% between 85 and 55 and in 28% below 55. The occipitofrontal circumference and the degree of ventricular enlargement had no correlation with the intellectual outcome in the children. Most prognostic value on the IQ had the age when reaching the developmental milestones, the degree of motor disability and the number of minor malformations. As there was no relation between the degree of hydrocephalus and the intellectual impairment, the conclusion can be made that associated anomalies of the CNS and defects in the cyto-architecture of the neocortex are more important factors in explaining mental retardation in cases of hydrocephalus.