Trends in Prevalence and Comorbidities of Children With Cerebral Palsy in Norway Born 1996 to 2010

Cerebral palsy (CP) is the most common cause of permanent motor disabilities in children, and one of the patient groups that receive the largest proportion of health care resources in high-income countries. CP is the result of a non-progressive injury in the immature brain that occurs before, during or after birth (neonatal period). The injury may be caused by a congenital brain abnormality, infection, trauma or other complications. Known risk factors include premature birth, restricted fetal growth and lack of oxygen during birth (birth asphyxia). Research shows that the panorama of causes has changed over time.

The clinical characteristics of CP vary considerably, something one would expect from the variation in potential causes. CP is categorized into subtypes based on the dominating symptoms and which part of the body is affected. Further classification is often based on the severity of the child's motor impairment. Also, children with CP often have additional comorbidities such as epilepsy, impaired vision and/or hearing, impaired ability to speak/communicate, cognitive disorders, and nutritional problems. Nor in these areas has the situation remained static over time.

During the last 20 years, both obstetric and neonatal care has undergone significant changes in Norway as well as in other countries. In the 1990s surfactant treatment of premature children was established, and in the early 2000s, therapeutic hypothermia was introduced as a new treatment for term born children with hypoxic ischemic encephalopathy (HIE). There have also been improvements in fetal monitoring during labor from around 2004 with an increase in the use of continuous electronic monitoring of the fetal heart using either the cardiotocography (CTG) or ST analysis (STAN) method to assess the baby's well-being, as well as Fetal scalp pH testing to determine if the baby is getting adequate oxygen supply. In this project, the investigators intend to study if the introduction of these new treatments has been associated with a decrease in the prevalence of CP and in changes in the clinical picture (e.g. less serious motor disabilities and comorbidities) for children born 1996 to 2010.

To study these questions, the investigators will take advantage of data from three national health registers: The Medical Birth Registry of Norway (MBRN), The Norwegian Patient Registry (NPR) and The Cerebral Palsy Registry of Norway (CPRN). While the MBRN has recorded all births since 1967, the NPR has recorded all patients treated in special health care service since 1997 and with their national identification numbers since 2008. All children with CP are diagnosed and their treatment assessed at pediatric habilitation centers, reporting to the NPR. The CPRN is a national medical quality register, owned by the South-Eastern Norway Regional Health Authority, and is located at the Vestfold Hospital Trust. Participation in the CPRN is based-on parental informed consent. This register has systematically recorded children with CP born since 1996, and has received high scores by The Norwegian Advisory Unit for Medical Quality Registries (SKDE). Moreover, the investigators have recently documented completeness and correctness of CP diagnoses in the CPRN as well as in the NPR. Thus, the use of data from these three high quality health registries provides a unique opportunity to study on a population level if the new obstetric and neonatal treatment options have been followed by measurable reductions in the prevalence of CP.

The purpose of the Cerebral Palsy Registry of Norway is to increase knowledge of the causes and treatment of children and youths with CP through surveillance and systematic analyses, including to: