Clinical and subclinical deficits at 8 years in a geographically defined cohort of low birthweight infants.
OBJECTIVE: To determine the prevalence of subclinical deficits in cognitive and motor function in low birthweight infants. DESIGN: Children of birth weight < or = 2000 g born to mothers resident in Merseyside in 1980-1 assessed using the Wechsler Intelligence Scale for Children (WISC), the Neale analysis of reading ability, and the Stott-Moyes-Henderson test of motor impairment (TOMI). Children attending normal schools assessed with controls matched for age, sex, and class in school. Children attending special schools were assessed unmatched. SUBJECTS: 233 matched index case-control pairs attending normal primary schools and 46 unmatched children attending special schools. SETTING: Primary and special schools. MAIN OUTCOME MEASURES: IQ score, reading age in months, and TOMI score. RESULTS: Index cases when compared with controls had a lower WISC score (mean IQ difference 8.8; 95% confidence interval (CI) 6.8 to 10.7), a lower reading age (mean difference 6.5 months; 95% CI 4.0 to 9.0), and poorer motor performance as shown by the TOMI score (mean difference 1.4; 95% CI 1.1 to 1.8). Of the children attending special schools, 23/46 (50%) had a WISC score < or = 50. CONCLUSIONS: Low birthweight children have significant subclinical deficits of cognitive and motor function and extra resources, especially in education, may be required to meet their needs.