Changing panorama of cerebral palsy in Sweden. VIII. Prevalence and origin in the birth year period 1991-94

This 8th Swedish population-based cerebral palsy (CP) report comprises 241 children born 1991-94. The live birth prevalence was 2.12 per 1000. Excluding 7 postnatally-derived cases, the gestational age-specific prevalences were 86 for extremely preterm children, 60 for very preterm and 6 for moderately preterm, and 1.3 for term children per 1000. Spastic hemiplegic, diplegic and tetraplegic subtypes accounted for 33%, 44% and 6%, dyskinetic CP for 12% and simple ataxia for 4%. Neuroimaging had been performed in 90%. Probable aetiology was identified in 73% of preterm and 86% of term children. Among preterm children it mas considered prenatal in 12%, peri/neonatal in 61% and unclassifiable in 27%, while it was 51%, 36% and 14% among term children. Conclusion: The live birth prevalence for CP in the birth year period 1991-94 continued to decrease slightly. Gestational age-specific prevalences increased marginally in extremely and very preterm births, continued to decrease in moderately preterm births and decreased slightly in term births. Probable aetiology and timing of the brain insult could be revealed in 80%, birth asphyxia being the likely cause in 28% of term children.