Hyperactivity in adolescents born very preterm is associated with decreased caudate volume.

Background: Several studies have associated preterm birth with impaired behavioral functioning and attention problems. In addition, preterm individuals have an increased risk of brain injury in the neonatal period. Such early lesions have the potential to disrupt subsequent neurodevelopment. This study explored behavioral functioning, particularly externalizing behavior, in a group of adolescents who were born very preterm and its relationship with volume of the caudate, a brain region particularly vulnerable to damage in the preterm neonate.
Methods: We studied 72 adolescents born before 33 weeks and 50 age- and gender-matched full-term control subjects. Behavioral assessment included the Rutter Behavioural Scale and a social adjustment scale. Bilateral caudate volumes were quantified by stereologic methods.
Results: Preterm adolescents scored significantly higher than control subjects on the Rutter hyperactivity score, and boys scored higher than girls. In preterm boys only, left caudate volume was negatively correlated with hyperactivity score (r = -.43, p = .018) and social adjustment score in childhood (r = -.40, p = .028).
Conclusions: Our data suggest that boys born very preterm are more likely to experience nonclinical behavioral problems in adolescence compared with full-term control subjects. Our results indicate that behavioral problems in this group might be associated with reductions in volume of the left caudate nucleus.