The Influence of Gestational Age on Severity of Impairment in Spastic Cerebral Palsy
Objective
To investigate the association between severity of impairment and gestational age in unilateral and bilateral spastic cerebral palsy, and to determine whether the influence of gestational age is independent of deviations from optimal birth weight.
Study design
The study group was a United Kingdom cohort of 4772 cases of spastic cerebral palsy born between 1960 and 1997, with information on birth demographics and severity of impairment. Generalized additive models were used to determine the proportions of cases severely impaired, by gestational age, and to determine whether gestational age or deviations from optimal birth weight better predicts severity of impairment.
Results
For unilateral spastic cerebral palsy, the proportions of severe impairments did not vary with gestational age. In contrast, for bilateral spastic cerebral palsy, the proportions of severe motor or cognitive impairments increased with increasing gestational age (e.g., from 20% to 50% between weeks 30 and 40 for cognitive impairment). For spastic cerebral palsy, gestational age is at least as good as deviation from optimal birth weight in predicting severity.
Conclusions
The severity of impairment increases with increasing gestational age in bilateral spastic cerebral palsy. This suggests differing etiologies in term and preterm infants and supports the theory that the developing brain is better able to compensate after a cerebral insult.
Abbreviations: HSBW, High standardized birth weight, LSBW, Low standardized birth weight, NSBW, Normal standardized birth weight, SBW, Standardized birth weight
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Karla Hemming was employed as a research assistant to Jane Hutton and Peter Pharoah under Medical Research grant G9900630, “Life expectancy in children and young adults with cerebral palsy: A UK collaboration.” The merging and cleaning of the database also was funded by this grant. Jennifer Kurinczuk was partially funded by National Public Health Career Scientist award PHCS022 from the National Coordinating Centre for Research Capacity Development. The Merseyside and Cheshire register is currently funded by the National Health Service. The North of England Collaborative Cerebral Palsy Survey receives grants from the Directors of Public Health of the Northern and Yorkshire Region and Primary Health Care Trusts. The 4Child - Four Counties Database of Cerebral Palsy, Vision Loss and Hearing Loss in Children is currently funded by the Department of Health under the Research Active Disease Registers Initiative and is based at the National Perinatal Epidemiology Unit, which is funded by the Department of Health. The Scottish Register of Children with Motor Deficit of Central Origin was originally set up at Glasgow University and funded by a grant from the Chief Scientist of the Scottish Office. The register was subsequently transferred to the care of the Information Services Division of the National Health Service, National Services Scotland. The Northern Ireland Cerebral Palsy Register is funded by the Department of Health, Social Services and Public Safety.
Jane Hutton and Peter Pharoah have acted as expert witnesses on life expectancy, for both plaintiffs and defendants, in medicolegal cases. The various funding sources had no involvement in the design, collection, analysis or interpretation of data, or the decision to submit for publication. The views expressed in this article are those of the authors and not necessarily those of the funding bodies. No author received any payment to produce the manuscript.
PII: S0022-3476(08)00177-7
doi:10.1016/j.jpeds.2008.02.041
© 2008 Mosby, Inc. All rights reserved.
