Alterations in the Relationship Between Hippocampal Volume and Episodic Memory Performance in Preterm Children

Abstract

This study examines the relationship between episodic memory and hippocampal volume (magnetic resonance imaging [MRI] volumetry) in preterm children with uncomplicated neonatal courses (<34 weeks of gestation, birth weight <2,000 g) and controls (7-11 years). To examine episodic memory performance and retrieval processes, neuropsychological tests and a recognition experiment were used. Although preterm children showed reduced hippocampal volumes relative to controls by 12%, episodic memory accuracy was not reduced. However, only in controls hippocampal volume correlated with some measures of episodic memory. Together, behavioral and MRI results indicate a minor functional specificity of the hippocampus regarding episodic memory functions in preterm children.

Modifications of Recognition Memory Processes in Preterm Children: An Event‐Related Potential Study

“…As expected and consistent with the analysis conducted with the larger sample in the Brunnemann et al. () study, the preterm group showed a smaller normalized volume than the control group for the left Hc, t (26) = 2.36, p < .05; preterm group = 2.51 cm 3 ; control group = 2.76 cm 3 ; and a marginally significant smaller volume for the right Hc, t (26) = 1.95, p = .06; preterm group = 2.70 cm 3 ; control group = 2.93 cm 3 . Highly similar results were obtained for the posterior two thirds of the Hc volumes: left posterior Hc, t (26) = 2.29, p < .05; preterm group = 1.52 cm 3 ; control group = 1.69 cm 3 ; and for the right posterior Hc, t (26) = 2.00, p = .06; preterm group = 1.69 cm 3 ; control group = 1.86 cm 3 .…”

“…Both child groups were subgroups of the sample examined in the larger volumetric analysis of Brunnemann et al. ().…”

White matter alterations to cingulum and fornix following very preterm birth and their relationship with cognitive functions

“…Smaller bilateral hippocampal volume in VPT samples compared to controls have been described from childhood to adult life (Aanes et al, 2015, Brunnemann et al, 2013, Nosarti et al, 2002), although in some studies significant between-group differences disappeared when correcting for intracranial volume (Omizzolo et al, 2013, Fraello et al, 2011). Hippocampal volume at term has been associated with working memory at age two (Woodward et al, 2005) and with episodic memory abilities at age seven (Thompson et al, 2013, Thompson et al, 2014, Omizzolo et al, 2013).…”

Alterations in development of hippocampal and cortical memory mechanisms following very preterm birth

“…Reductions in volume in the hippocampus, as well as the interconnected thalamus and posterior cingulate cortex, are already present at term‐equivalent age and are related to the degree of prematurity 11. Smaller bilateral hippocampal volume in VPT samples compared with controls has been described at school‐age (~9% volume reduction),12, 13 adolescence (~14% volume reduction),14, 15 and adulthood16, 17 although some studies have found no hippocampal volume differences when correcting for factors such as intracranial volume 18, 19. Interestingly, hippocampal volume at term, but not at 7 years of age (or the amount of growth between these time‐points), has been associated with episodic memory abilities at age seven 12, 18, 20.…”