Cross-sectional study of the association of cognitive function and hippocampal volume among healthy elderly adults

BACKGROUND: Cognitive impairment and dementia among elderly adults is a pressing public health issue in China but research on biomarkers of cognitive decline has been limited. AIM: Explore the relationship between multiple domains of cognitive functioning and the volume of the left and right hippocampus in healthy elderly adults. METHODS: Structural MRI scanning was performed on 65 community-dwelling healthy participants 65 to 75 years of age using the Siemens 3.0 T Trio Tim with the MPRAGE sequence. The volumes of the left and right hippocampus were determined using Freesurfer software. Cognitive functioning was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Both unadjusted and adjusted associations between the hippocampal volumes and cognitive functioning were estimated. RESULTS: Within this relatively narrow age range, age was significantly associated with most of the cognitive measures assessed in women but was not significantly associated with any of the cognitive measures in men. In both men and women right hippocampal volume was positively associated with delayed memory and left hippocampal volume was positively associated with both immediate memory and delayed memory (though the relationship with delayed memory in women was only at a trend level). After adjustment for age, gender, and years of formal education (the variable that was most strongly associated with all of the cognitive measures), both left hippocampal volume and right hippocampal volume were positively associated with delayed memory, but not with immediate memory. Interestingly, the difference in the volumes of the left and right hippocampi was negatively associated with the score of the RBANS attention subscale, a relationship that was stronger in women than in men. CONCLUSIONS: This study confirms previous work about the relationship of hippocampal volume and memory, identifies a possible relationship between attention and the difference in size of the two hippocampi, and suggests that there may be some differences in these relationships by gender.