Hippocampal volumes of 184 preterm (PT) and 32 full-term (FT) infants were measured by segmental MRI at term equivalent age in an investigation of correlations of preterm hippocampal volume, perinatal risk factors, and neurodevelopmental outcome, at University of Melbourne, Victoria, and other centers in Australia; St Louis and Boston, USA; and Geneva, Switzerland. No significant differences between PT and FT infant hippocampal volumes were detected, after controlling for head size. Factors associated with significantly smaller hippocampal volumes included white matter injury, exposure to postnatal steroids, and treatment with indomethacin. Smaller PT hippocampal volumes correlated with impaired cognitive and psychomotor development measured by the Bayley Scales at 2 years of age, after correcting for head size and sex. [1]

COMMENT. The hippocampus, part of the limbic lobe, originally linked mainly with olfactory function, is now considered important in memory, spatial function, and cognition. Hippocampal volume reduction reported in children with chromosome 22qll.2 deletion syndrome is correlated with severity of cognitive impairment [2]. Severe memory impairment is reported in a 5-year-old child with marked hippocampal atrophy after prolonged status epilepticus [3]. The authors of the above report in infants recommend further MRI studies in older children to determine the role of the hippocampus in the high rate of cognitive impairment in preterm infants tested at a later age. They advocate interventions to decrease white matter damage and overuse of postnatal steroids and indomethacin in preterm infants, factors linked to smaller hippocampal volume.