The present study aimed, first, to analyse in detail early sleep states in 21 preterm infants born before the 33rd week of gestational age and compare them with sleep states in 23 fullterm infants assessed at gestationally matched ages in the first six months. Second, to determine whether analyses of early sleep states in preterm infants may enable identification of infants with future developmental disabilities. In addition to evaluations of perinatal risk factors, neurological condition, psychological development, and social environment during the first year of life, examinations of psychological and neurological development and the assessment of the social environment at 3 and 9 years were carried out. Measures of perinatal status and sleep states up to the age of 40 weeks gestational age did not correlate with outcome measures at 3 and 9 years. However, the polygraphic measures of sleep states at 12 and 24 weeks corrected age, predicted the 3-year developmental outcomes. The complexity of these measures may contribute to their predictive validity for the outcomes at 3 years. Measures of the social environment at 3 and 9 years contributed significantly to the prediction of 9-year developmental outcomes. These results indicate that environmental factors may become more important with age. The detailed analysis of early sleep patterns may enable the early identification of infants who need special care and intervention.
Regional white matter development in very preterm infants: perinatal predictors and early developmental outcomes
