Prevalence Estimate of Cerebral Palsy in Northern Alberta: Births, 2008-2010.

OBJECTIVES: The objectives of this study were to determine prevalence estimates of cerebral palsy (CP) among 5-year-old children in northern Alberta; to provide congenital, gestational age- and birth weight-specific, and postneonatal CP rates; and to describe motor subtypes and function.

METHODS: This population-based prevalence estimate study, part of the Canadian Cerebral Palsy Registry, reports confirmed CP diagnoses at age 5 years made by pediatric rehabilitation and child neurology specialists. Prevalence rates with 95% confidence intervals (CIs) used Alberta government denominators of same-age children and live births.

RESULTS: The Northern Alberta CP rate (birth years, 2008-2010) for 173 5-year-old children is 2.22 (95% CI 2.12, 2.32) per 1000 5-year-old children. The congenital CP rate is 1.99 (95% CI, 1.89-2.09) per 1000 live births; unilateral congenital CP, 1.0 (95% CI, 0.64-1.36) per 1000 live births; and postneonatal CP, 0.12 (95% CI, 0.1-0.14) per 1000 live births. Gestational age-specific rates are similar: age <28 weeks, 27.2 (95% CI, 23.05-31.35) and 28 to 31 weeks, 29.5 (95% CI, 25.78-33.22). Motor subtypes for 169 children (data missing, 4; male, 97; postnatal, 9) are: spastic, 148 (87.6%) including 31 (20.9%) with diplegia, 10 (6.8%) triplegia, 33 (22.2%) quadriplegia, 74 (50%) hemiplegia/monoplegia); and dyskinetic, 18 (10.6%) and ataxic, 3 (1.8%). A total of 107 (63.3%) ambulate without assistive devices and 111(65.7%) handle most objects with their hands independently.

CONCLUSIONS: This is the fourth Canadian CP prevalence study; one from Quebec used a similar case ascertainment approach and two 1980s studies from Alberta and British Columbia used administrative databases. Northern Alberta CP rates are comparable with other developed countries. The hemiplegic subtype is the most common. Rates among preterm children have declined but are similar for the <28 and 28 to 31 gestation-week groups.