Participants’ neonatal and socio-demographic variables
| Very preterm (n = 64) | Control (n = 36) | Test statistic | p value | |
|---|---|---|---|---|
| Age (mean ± SD) | 31.53 ± 2.44 | 30.47 ± 6.36 | U = 806.0 | 0.013 |
| Sex (M/F) | 36/28 | 21/15 | χ2 = 0.041 | 1.000 |
| IQ | ||||
| Verbal IQ | 97 ± 18.37 | 107.73 ± 16.33 | U = 1159.5 | 0.017 |
| Performance IQ | 104.95 ± 14.90 | 109.72 ± 15.59 | U = 1017.5 | 0.112 |
| Gestational age | 29.48 ± 1.98 | -- | -- | -- |
| Birthweight | 1311.12 ± 376.41 | -- | -- | -- |
| Neonatal ultrasound (brain injury/normal)a | 28/36 | -- | -- | -- |
| Handedness (L/R/A)b^ | 11/52/1 | 1/28/0 | Fisher’s exact = 3.838 | 0.12 |
| Socioeconomic status*a | ||||
| I-II (professional and Intermediate) | 27 | 15 | Fisher’s exact = 5.195 | 0.241 |
| III (skilled manual and non-manual) | 26 | 15 | ||
| IV-V (semi-skilled and unskilled manual) | 2 | 0 | ||
| Students | 1 | 4 | ||
| Unemployed | 7 | 2 |
p values that remained significant after FDR correction are indicated in bold.
* Her Majesty’s Stationary Office (1991), missing information for one participant.
↵a Neonatal brain injury includes uncomplicated periventricular hemorrhage without ventricular dilation and periventricular hemorrhage with ventricular dilation (Stewart et al., 1983).
b Fisher’s exact test.
^ Missing information for seven control participants.