Epidemiology of infantile hydrocephalus in Sweden: a clinical follow-up study in children born at term.

The long-term outcome of infantile hydrocephalus (IH) in children born at term during a period of active shunt treatment was studied in a population-based survey. The series consisted of 68 children greater than or equal to 6 years old and born in 1967-78 in the south-western Swedish health care region. The clinical follow-up included neuro-paediatric assessment, Stott's test of motor impairment, the WISC test, CT and EEG analyses. Nineteen of the 68 children (28%) had cerebral palsy, 17 (25%) minor motor dysfunction and 32 (47%) no motor dysfunction; mental retardation was present in 26 (38%), 16 with an IQ 50-70 and 10 with IQ less than 50; 42 children (62%) had normal intelligence and epilepsy was found in 15 (22%). Compared with a non-shunted IH series from the 1950s, the survival of IH children had considerably increased. Of constituents characterizing the IH syndrome from the time prior to shunting, ataxia, divergent squint and the special "Cocktail-party behaviour" had significantly decreased, all of which conditions are highly related to chronic expansion of the ventricular system. The frequencies of other impairments such as mental retardation and epilepsy were fairly similar, reflecting the present increased survival of IH children with primarily non-IH-dependent brain damage. IH children with associated brain parenchymal defects had the poorest outcome, and those without had in general a much more favourable one. Thus the single most important factor for the outcome of IH was found to be the presence or absence of associated primary brain damage or maldevelopment.