Outcome | 1991–1992 | 1997 | 2005 |
---|---|---|---|

n = 210 | n = 142 | n = 147 | |

Neurosensory | |||

Major neurosensory disability,^{a} n (%) | 38 (18) | 22 (15) | 26 (18) |

Any cerebral palsy, n (%) | 27 (13) | 15 (11) | 20 (14) |

Moderate or severe^{b} | 13 (6) | 9 (6) | 11 (7) |

Blindness, n (%) | 2 (1) | 3 (2) | 0 (0) |

Deafness, n (%) | 3 (1) | 3 (2) | 5 (3) |

IQ z score, mean (SD) | −0.70 (1.26) | −0.80 (1.11) | −0.74 (1.22) |

IQ z score −2 SD to <−1 SD, n (%) | 39 (19) | 47 (33) | 29 (20) |

IQ z score <−2 SD, n (%) | 30 (14) | 14 (10) | 20 (14) |

Academic achievement | |||

Word reading z score, mean (SD); n | −0.39 (1.10); 200 | −0.51 (1.12); 132 | −0.87 (1.14); 140 |

<−2 SD, n (%) | 19 (10) | 11 (8) | 23 (16) |

Spelling z score, mean (SD); n | −0.34 (0.86); 199 | −0.50 (1.07); 134 | −0.87 (1.18); 138 |

<−2 SD, n (%) | 6 (3) | 7 (5) | 20 (14) |

Mathematics z score, mean (SD); n | −0.57 (0.96); 197 | −0.53 (1.16); 131 | −0.94 (1.26); 140 |

<−2 SD, n (%) | 12 (6) | 13 (10) | 32 (23) |

Major neurosensory disability; 2005 compared with 1991–1992: OR 0.80, 95% CI, 0.34 to 1.92,

*P*= .62; 2005 compared with 1997: OR 0.99, 95% CI, 0.44 to 2.23,*P*= .99. Moderate or severe cerebral palsy; 2005 compared with 1991–1992: OR 1.23, 95% CI, 0.53 to 2.83,*P*= .63; 2005 compared with 1997: OR 1.18, 95% CI, 0.47 to 2.96,*P*= .72. OR and 95% CIs not calculated for blindness or deafness because rates were too low.↵a Any of moderate or severe cerebral palsy, blindness, deafness, or an IQ

*z*score <−2 SD.↵b Cerebral palsy severity defined by either functional classification (1991–1992 cohort) or the GMFCS (1997 and 2005 cohorts); moderate (walking with considerable difficulty, with or without appliances, GMFCS level 2 or 3), or severe (unable to walk, GMFCS level 4 or 5).