Psychological test scores in those able to be tested at each age for extremely low birthweight (ELBW) and normal birthweight (NBW) children
| ELBW | NBW |
Mean difference (95% CI) | |
| MDI at 2 | 90.7 (17.1) | 105.8 (16.4) | 15.1 (8.9 to 21.3) |
| n=74 | n=48 | ||
| WPPSI at 5 | 102.1 (16.2) | 113.8 (15.6) | 11.7 (5.6 to 17.8) |
| n=72 | n=44 | ||
| WISC-R at 8 | 96.3 (15.0) | 109.6 (15.7) | 13.3 (7.8 to 18.8) |
| n=77 | n=52 | ||
| WISC-III, Verbal Scale, at 14 | 90.1 (16.5) | 103.2 (13.7) | 13.1 (7.0 to 19.2) |
| n=73 | n=41 |
Data are mean (SD). MDI, Mental Developmental Index; WPPSI, Wechsler Preschool and Primary Scale of Intelligence; WISC-R, Wechsler Intelligence Scale for Children-Revised; WISC-III, Wechsler Intelligence Scale for Children, 3rd edition.