Hippocampal atrophy in people with memory deficits: results from the population-based IPREA study.

Background:Clinical studies have shown that hippocampal atrophy is present before dementia in people withmemory deficits and can predict dementia development. The question remains whether this association holdsin the general population. This is of interest for the possible use of hippocampal atrophy to screen populationfor preventive interventions. The aim of this study was to assess hippocampal volume and shape abnormalitiesin elderly adults with memory deficits in a cross-sectional population-based study.Methods:We included individuals participating in the Italian Project on the Epidemiology of AlzheimerDisease (IPREA) study: 75 cognitively normal individuals (HC), 31 individuals with memory deficits (MEM),and 31 individuals with memory deficits not otherwise specified (MEMnos). Hippocampal volumes and shapewere extracted through manual tracing and the growing and adaptive meshes (GAMEs) shape-modelingalgorithm. We investigated between-group differences in hippocampal volume and shape, and correlationswith memory deficits.Results:In MEM participants, hippocampal volumes were significantly smaller than in HC and weremildly associated with worse memory scores. Memory-associated shape changes mapped to the anteriorhippocampus. Shape-based analysis detected no significant difference between MEM and HC, while MEMnosshowed shape changes in the posterior hippocampus compared with HC and MEM groups.Conclusions:These findings support the discriminant validity of hippocampal volumetry as a biomarker ofmemory impairment in the general population. The detection of shape changes in MEMnos but not in MEMparticipants suggests that shape-based biomarkers might lack sensitivity to detect Alzheimer’s-like pathologyin the general population.