Quantitative MRI measurements of the sagittal surface area of the corpus callosum (CC) in 72 preterm individuals tested at adolescence (14-15 years) were compared with verbal skills on neuropsychological tests in a study at the Institute of Psychiatry, De Crespigny Park, London, UK. Total CC area in very preterm adolescents was 7.5% smaller than in controls (p=0.015). In preterm individuals who had a periventricular hemorrhage in the neonatal period, the decrease in CC area was greater. Verbal IQ and verbal fluency scores were lower in male adolescents with reduced total mid-sagittal CC size and mid-posterior surface area. 
COMMENT. The development of the corpus callosum (CC), especially the posterior quarter adjacent to the periventricular region, is adversely affected by very preterm birth. The decreased size of the CC is correlated with lower verbal IQ and verbal fluency scores in preterm boys at adolescence.
A decrease in size of the splenium of the corpus callosum is reported in ADHD children compared to controls (Semrud-Clikeman et al. 1994; see Ped Neur Briefs July 1994).