Cerebral ventricular volume and temperamental difficulties in infancy. The Generation R Study.

BACKGROUND: Numerous studies have provided evidence for subtle deviations in brain morphology in children with psychiatric disorders, but much less is known about the onset and developmental trajectory of these deviations early in life. We sought to determine whether variances in cerebral ventricular size in fetuses and newborns are associated with temperamental difficulties in infants.
METHODS: Within a population-based cohort study, we measured the size of the lateral ventricle of the fetus' brain twice during pregnancy. We used 3-dimensional cranial ultrasound to measure the cerebral ventricular volume of infants at age 6 weeks. We then related the size of the cerebral ventricular system to temperamental dimensions at age 3 months using the Mother and Baby Scales, and at age 6 months using the Infant Behavior Questionnaire for a total of 1028 infants.
RESULTS: The size of the lateral ventricle of the fetuses in midpregnancy was not related to temperamental difficulties in infants; however, smaller lateral ventricles in late pregnancy were associated with higher activity levels at the age of 6 months. Infants with smaller ventricular volumes at age 6 weeks experienced higher activity levels, more anger or irritability and poorer orienting later in infancy. Children with the lowest ventricular volumes scored on average 0.15 (95% confidence interval 0.06-0.23, p = 0.001) points higher (23%) on activity levels than children with the highest ventricular volumes.
CONCLUSION: Variations in ventricular size before and shortly after birth are associated with temperamental difficulties. Some of the morphologic differences between children with and without psychiatric disorders may develop very early in life.