Hippocampal sclerosis of aging at post-mortem is evident on MRI more than a decade prior

INTRODUCTION: Hippocampal sclerosis of aging (HS) is an important component of combined dementia neuropathology. However, the temporal evolution of its histologicallydefined features is unknown. We investigated pre-mortem longitudinal hippocampal atrophy associated with HS, as well as with other dementia-associated pathologies. METHODS: We analyzed hippocampal volumes from MRI segmentations in 64 dementia patients with longitudinal MRI follow-up and post-mortem neuropathological evaluation, including HS assessment in the hippocampal head and body. RESULTS: Significant HS-associated hippocampal volume changes were observed thoughout the evaluated timespan, up to 11.75 years before death. These changes were independent of age and Alzheimer’s Disease (AD) burden, and specifically driven by CA1 and subiculum. AD burden, but not HS, significantly associated with the rate of hippocampal atrophy. DISCUSSION: HS-associated volume changes are detectable on MRI earlier than 10 years before death. These findings could contribute to the derivation of volumetric cutoffs for in vivo differentiation between HS and AD.