Relation of neural structure to persistently low academic achievement: A longitudinal study of children with differing birth weights

Objective: This study examined the relation of cerebral tissue reductions associated with VLBW to patterns of growth in core academic domains. Method: Children born <750 g, 750 to 1,499 g, or >2,500 g completed measures of calculation, mathematical problem solving, and word decoding at time points spanning middle childhood and adolescence. K. A. Espy, H. Fang, D. Charak, N. M. Minich, and H. G. Taylor (2009, Growth mixture modeling of academic achievement in children of varying birth weight risk, Neuropsychology, Vol. 23, pp. 460-474) used growth mixture modeling to identify two growth trajectories (clusters) for each academic domain: an average achievement trajectory and a persistently low trajectory. In this study, 97 of the same participants underwent magnetic resonance imaging (MRI) in late adolescence, and cerebral tissue volumes were used to predict the probability of low growth cluster membership for each domain. Results: Adjusting for whole brain volume (wbv), each 1-cm³ reduction in caudate volume was associated with a 1.7- to 2.1-fold increase in the odds of low cluster membership for each domain. Each 1-mm² decrease in corpus callosum surface area increased these odds approximately 1.02-fold. Reduced cerebellar white matter volume was associated specifically with low calculation and decoding growth, and reduced cerebral white matter volume was associated with low calculation growth. Findings were similar when analyses were confined to the VLBW groups. Conclusions: Reduced volume of structures involved in connectivity, executive attention, and motor control may contribute to heterogeneous academic trajectories among children with VLBW.