TABLE 2.
Comparisons of WISC-III scores between preterm and term children at 12 years of chronological age
| Preterm N=375 |
Term N=111 |
Adjusted Mean Difference or Odds Ratio (95%CI) - All children included | Adjusted Mean Difference or Odds Ratio (95%CI) - Children with severe brain injury excluded * | |||
|---|---|---|---|---|---|---|
| IQ | n |
Mean (SD) |
n |
Mean (SD) |
|
|
| WISC-III | ||||||
| Verbal IQ | 369 | 90.8 (18.9) | 111 | 103.9 (16.0) | −10.8 (−14.3, −7.3)+ | −8.9 (−12.0,−5.7)+ |
| Performance IQ | 367 | 86.8 (17.9) | 111 | 103.1 (15.7) | −14.6 (−18.1, −11.1)+ | −12.7 (−15.9, −9.5)+ |
| Full Scale IQ | 366 | 87.9 (18.3) | 111 | 103.8 (15.7) | −13.7 (−17.1, −10.3)+ | −11.7 (−14.7, −8.7)+ |
| Verbal comprehension | 369 | 92.3 (18.6) | 108 | 104.3 (15.4) | −9.9 (−13.4, −6.5)+ | −8.1 (−11.2, −4.9)+ |
| Perceptual organization | 367 | 86.9 (17.7) | 111 | 102.9 (15.8) | −14.6 (−18.1, −11.2)+ | −12.8 (−16.0, −9.6)+ |
| Freedom of distractibility | 367 | 89.9 (16.8) | 110 | 101.7 (16.4) | −10.1 (−13.5, −6.8)+ | −8.3 (−11.5, −5.1)+ |
| Processing speed | 361 | 94.5 (19.9) | 108 | 108.5 (16.7) | −12.0 (−15.9, −8.0)+ | −10.0 (−13.7, −6.3)+ |
| Subtest scaled score | ||||||
| Information | 368 | 8.7 (3.8) | 110 | 10.7 (3.6) | −1.6 (−2.3, −0.9)+ | −1.3 (−2.0, −0.6)+ |
| Similarities | 369 | 8.9 (3.5) | 111 | 11.1 (3.1) | −1.8 (−2.5, −1.2)+ | −1.5 (−2.1, −0.9)+ |
| Arithmetic | 366 | 7.7 (3.4) | 111 | 10.3 (3.6) | −2.4 (−3.1, −1.6)+ | −2.0 (−2.7, −1.3)+ |
| Vocabulary | 365 | 8.8 (3.8) | 110 | 10.7 (3.0) | −1.5 (−2.2, −0.8)+ | −1.2 (−1.9, −0.6)+ |
| Comprehension | 368 | 7.8 (3.9) | 111 | 10.3 (3.3) | −2.1 (−2.8, −1.3)+ | −1.7 (−2.4, −1.0)+ |
| Digit span | 369 | 8.4 (3.2) | 110 | 10.0 (3.0) | −1.3 (−1.9, −0.6)+ | −1.0 (−1.6, −0.4)+ |
| Picture completion | 368 | 8.0 (3.4) | 111 | 10.1 (2.9) | −2.0 (−2.7, −1.3)+ | −1.7 (−2.4, −1.0)+ |
| Coding | 365 | 8.4 (3.8) | 110 | 10.6 ( 3.4) | −1.7 (−2.4, −0.9)+ | −1.4 (−2.1, −0.6)+ |
| Picture arrangement | 367 | 7.9 (3.8) | 111 | 10.5 (3.5) | −2.3 (−3.1, −1.6)+ | −2.0 (−2.7, −1.3)+ |
| Block design | 368 | 7.7 (3.9) | 111 | 11.2 (3.7) | −3.1 (−3.9, −2.3)+ | −2.7 (−3.5, −2.0)+ |
| Object assembly | 367 | 7.0 (3.5) | 111 | 9.7 (3.0) | −2.4 (−3.1, −1.7)+ | −2.1 (−2.8, −1.5)+ |
| Symbol search | 363 | 9.1 (4.3) | 109 | 12.4 (3.5) | −3.0 (−3.8, −2.1)+ | −2.6 (−3.4, −1.7)+ |
| WISC-III, No (%) | ||||||
| Verbal IQ <70 | 42/369 (11.4%) | 1/111 (0.9%) | 14.0 (1.9, 105.1) ++ | 11.1 (1.4, 87.6) ++ | ||
| Performance IQ <70 | 61/367 (16.6%) | 0 | - | - | ||
| Full Scale IQ <70 | 52/366 (14.2%) | 0 | - | - | ||
Adjustement for male gender, maternal age < 20, maternal years of education, minority status, single-parent household.
*
Severe brain injury: grade 3 and 4 IVH, PVL, grade 2 and above ventriculomegaly
+
P-value < 0.005
++
p-value <0.05