Brain Advance Access originally published online on September 17, 2008
Brain 2008 131(11):2986-2994; doi:10.1093/brain/awn227
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Preterm infant hippocampal volumes correlate with later working memory deficits
1Murdoch Childrens Research Institute, 2Departments of Psychology and Obstetrics and Gynaecology, University of Melbourne, 3Howard Florey Institute, 4The Royal Women's Hospital, Melbourne, Australia and 5School of Medicine, Washington University, St Louis, USA
Correspondence to: Peter J. Anderson, School of Behavioural Science, The University of Melbourne, Melbourne, VIC 3010, Australia E-mail: peterja{at}unimelb.edu.au
Children born preterm exhibit working memory deficits. These deficits may be associated with structural brain changes observed in the neonatal period. In this study, the relationship between neonatal regional brain volumes and working memory deficits at age 2 years were investigated, with a particular interest in the dorsolateral prefrontal cortex, parietal cortex and the hippocampus. While the eligible sample consisted of 227 very preterm children who were born at the Royal Women's Hospital, Melbourne prior to 30 weeks gestation or weighing <1250 g, 156 children had complete data sets. Neonatal magnetic resonance images of the brain were obtained at term equivalent age and subsequently parcellated into eight sub-regions, while the hippocampus was manually segmented. The relationship between brain volumes for these regions and performance on a working memory task (delayed alternation) at 2 years of age was examined. Very preterm children who perseverated on the working memory task had significantly smaller hippocampal volumes than very preterm children who exhibited intact working memory, even after adjusting for relevant perinatal, sociodemographic and developmental factors. Preterm children appear to have altered hippocampal volumes by discharge from hospital which may have a lasting impact on working memory function.
Key Words: prematurity; extremely low birth weight; working memory; hippocampus; magnetic resonance imaging
Abbreviations: ALTD, alternated; BSID-II, Bayley Scales of Infant Development-II; FAIL, failed training; GA, gestational age; MDI, mental developmental index; PERS, perseverated; TBV, total brain volume; TEA, term equivalent age; WMI, white matter injury
Received March 20, 2008. Revised July 29, 2008. Accepted August 24, 2008.