Stability of Cognitive Outcome From 2 to 5 Years of Age in Very Low Birth Weight Children

OBJECTIVE: This study assessed the stability of cognitive outcomes of premature, very low birth weight (VLBW; <= 1500 g) children. METHODS: A regional cohort of 120 VLBW children born between 2001 and 2004 was followed up by using the Bayley Scales of Infant Development, Second Edition, at 2 years of corrected age and the Wechsler Preschool and Primary Scale of Intelligence-Revised at the age of 5 years. The Mental Development Index (MDI) and the full-scale IQ (FSIQ) were measured, respectively. A total of 168 randomly selected healthy term control children born in the same hospital were assessed for MDI and FSIQ. RESULTS: In the VLBW group, mean +/- SD MDI was 101.2 +/- 6 16.3 (range: 50-128), mean FSIQ was 99.3 +/- 6 17.7 (range: 39-132), and the correlation between MDI and FSIQ was 0.563 (P < .0001). In the term group, mean MDI was 109.8 +/- 11.7 (range: 54-128), mean FSIQ was 111.7 +/- 14.5 (range: 73-150), and the correlation between MDI and FSIQ was 0.400 (P < .0001). Overall, 83% of those VLBW children who had significant delay (-2 SD or less) according to MDI had it also in FSIQ. Similarly, 87% of those children who were in the average range in MDI were within the average range in FSIQ as well. CONCLUSIONS: Good stability of cognitive development over time was found in VLBW children and in term children between the ages of 2 and 5 years. This conclusion stresses the value and clinical significance of early assessment at 2 years of corrected age. However, we also emphasize the importance of a long-term follow-up covering a detailed neuropsychological profile of these at-risk children. Pediatrics 2012; 129:503-508