Mediation of the relationship between gestational age and IQ by GMV in preterm children (gestational age range: 24–32 completed weeks’ gestation).

<p>The direct effect predicting full scale IQ by GA controlling GMV volume is displayed in brackets. Coefficients are standardized regression coefficients controlled for age, sex, and maternal education. Explained variance (Δ<i>r</i>) is derived from a model that entered the predictor in a separate step holding covariates constant. * P < 0.05, ** P < 0.01.</p

Means and bias corrected bootstrap confidence intervals for five gestational age groups adjusted for age, sex, and maternal education.

<p>Means and bias corrected bootstrap confidence intervals for five gestational age groups adjusted for age, sex, and maternal education.</p

Brain volumes and cognitive functions by gestational age groups.

<p><b>A)</b> Mean values and standard errors of Gray Matter Volume (GMV) and White Matter Volume (WMV) based on 1000 bootstrap samples by five gestational age groups (children born 24–27 completed weeks’ gestation, 28–29 completed weeks’ gestation, 30–31 completed weeks’ gestation, 32 completed weeks’ gestation and term born children) controlling age, sex, and maternal education. <b>B)</b> Mean values and standard errors of cognitive functions (IQ score normative mean = 100, SD = 15) based on 1000 bootstrap samples by five gestational age groups (children born 24–27 completed weeks’ gestation, 28–29 completed weeks’ gestation, 30–31 completed weeks’ gestation, 32 completed weeks’ gestation and term born children) controlling age, sex, and maternal education. * P < 0.05, ** P < 0.01, *** P < 0.001.</p

Regional differences of gray matter volume.

<p>Significant difference of GMV A) Contrast between children born 24–27 completed weeks’ gestation and term born children showing significantly decreased cortical GMV in one cluster in the right middle and superior temporal gyrus (MNI-coordinates: 56–6–15) with a cluster size of 542 voxel in the preterm group. B) Contrast between children born 28–29 completed weeks’ gestation and term born children showing significantly decreased cortical GMV in one cluster in the right middle and superior temporal gyrus (MNI-coordinates: 57–16–12), with a cluster size of 1487 voxel in the preterm group. C) Contrast between children born 32 completed weeks’ gestation and term born children showing significantly decreased cortical GMV in the left insula (MNI-coordinates: -32 6–15), with a cluster size of 145 voxel in the preterm group. The color bars represent the t-scores.</p

Descriptive statistics for study variables (<i>N</i> = 106).

<p>Descriptive statistics for study variables (<i>N</i> = 106).</p