Research article

Hippocampal volumes are important predictors for memory function in elderly women

Martin A Ystad¹ , Astri J Lundervold^2,3 , Eike Wehling² , Thomas Espeseth⁴ , Helge Rootwelt⁵ , Lars Tjelta Westlye⁴ , Martin Andersson^2,3 , Steinunn Adolfsdottir² , Jonn Terje Geitung^6,3 , Anders M Fjell⁴ , Ivar Reinvang⁴ and Arvid Lundervold^1,7

¹Department of Biomedicine, Neuroinformatics and Image Analysis Laboratory, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway

²Department of Biological and Medical Psychology, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway

³Kavli's Dementia Research Centre, Haraldsplass Deaconess Hospital, 5009 Bergen, Norway

⁴Center for the Study of Human Cognition, University of Oslo, POB 1094, Blindern, 0317 Oslo, Norway

⁵Department of Medical Biochemistry, Rikshospitalet University Hospital, 0027 Oslo, Norway

⁶Department of Radiology, Haraldsplass Deaconess University Hospital, 5009 Bergen, Norway

⁷Department of Radiology, Haukeland University Hospital, 5021 Bergen, Norway

author email corresponding author email

BMC Medical Imaging 2009, 9:17doi:10.1186/1471-2342-9-17

Published:	22 August 2009

Abstract

Background

Normal aging involves a decline in cognitive function that has been shown to correlate with volumetric change in the hippocampus, and with genetic variability in the APOE-gene. In the present study we utilize 3D MR imaging, genetic analysis and assessment of verbal memory function to investigate relationships between these factors in a sample of 170 healthy volunteers (age range 46–77 years).

Methods

Brain morphometric analysis was performed with the automated segmentation work-flow implemented in FreeSurfer. Genetic analysis of the APOE genotype was determined with polymerase chain reaction (PCR) on DNA from whole-blood. All individuals were subjected to extensive neuropsychological testing, including the California Verbal Learning Test-II (CVLT). To obtain robust and easily interpretable relationships between explanatory variables and verbal memory function we applied the recent method of conditional inference trees in addition to scatterplot matrices and simple pairwise linear least-squares regression analysis.

Results

APOE genotype had no significant impact on the CVLT results (scores on long delay free recall, CVLT-LD) or the ICV-normalized hippocampal volumes. Hippocampal volumes were found to decrease with age and a right-larger-than-left hippocampal asymmetry was also found. These findings are in accordance with previous studies. CVLT-LD score was shown to correlate with hippocampal volume. Multivariate conditional inference analysis showed that gender and left hippocampal volume largely dominated predictive values for CVLT-LD scores in our sample. Left hippocampal volume dominated predictive values for females but not for males. APOE genotype did not alter the model significantly, and age was only partly influencing the results.

Conclusion

Gender and left hippocampal volumes are main predictors for verbal memory function in normal aging. APOE genotype did not affect the results in any part of our analysis.