Selective improvement in cognitive test scores of extremely low birthweight infants aged between 2 and 5 years

Abstract

Abstract The cognitive development at 2 and 5 years of a cohort of extremely low birthweight (ELBW) children (birthweight 500‐999 g) was compared with that of cohorts of larger very low birthweight (VLBW) children (birthweight 1000‐1500 g) and normal birthweight (NBW) children (birthweight > 2500 g) to determine whether the improvements in cognitive function of ELBW infants between 2 and 5 years are apparent or real. At 2 years of age, ELBW children had a mean Mental Developmental Index (MDI) on the Bayley Scales of 90.4, significantly lower than the means of 100.3 for the larger VLBW children (P= 0.006), and 107.8 for the NBW children (P= 0.0002). However by 5 years the mean scores on the W..