The changing panorama of cerebral palsy in Sweden. X. Prevalence and origin in the birth-year period 1999-2002

Aim: The aim of the study was to describe the prevalence and origin of cerebral palsy (CP), which is the tenth report from the western Swedish study. Methods: A population-based study covering 85 737 live births in the area in 1999-2002. Birth characteristics and neuroimaging findings were recorded, prevalence of CP was calculated and aetiology was analysed. Results: CP was found in 186 children. The crude prevalence was 2.18 per 1000 live births. The gestational age-specific prevalence for < 28 gestational weeks was 55.6 per 1000 live births, whereas it was 43.7 for 28-31 weeks, 6.1 for 32-36 weeks and 1.43 per 1000 for > 36 weeks. There was a female majority among children born at term and a male predominance in children born preterm. Hemiplegia accounted for 38%, diplegia for 32%, tetraplegia for 7%, whereas 17% had dyskinetic CP and 5% ataxia. Neuroimaging showed white-matter lesions in 31% and cortical/subcortical lesions in 29%. The aetiology was considered to be prenatal in 36%, peri/neonatal in 42%, whereas it remained unclassified in 21%. Conclusion: The decrease in CP prevalence observed since the 1980s had ceased. An increase in children born at term and in dyskinetic CP was found. In children born before 28 weeks of gestation, the prevalence decreased significantly. White-matter and cortical/subcortical lesions dominated on neuroimaging.