Hippocampal subfield volumes correlate with subjective, but not objective, memory in older adults with normal neuropsychological test performance

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Linda MAH^1,3 (lmah@research.baycrest.org), Susan VANDERMORRIS², Nicolaas Paul L.G. VERHOEFF^2,3, Nathan HERRMANN³; ¹Rotman Research Institute, Baycrest, University of Toronto, ²Baycrest Health Sciences, ³Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto

Subjective cognitive decline (SCD), defined as perception of memory or cognitive impairment with normal test performance, may be a preclinical stage of Alzheimer’s disease (AD). Self-perception of frequency of memory slips correlates with neuroimaging markers of AD including cerebral amyloid deposition and functional connectivity of the hippocampus and posterior default mode network. Here we measured hippocampal subfield volumes in cognitively unimpaired older adults and examined their association with frequency of forgetting and verbal memory. Participants were 51 older adults (23M, age 71.0 SD=6.3) with normal neuropsychological test performance who completed the Memory Functioning Questionnaire (MFQ) and a high-resolution T2-weighted scan of the medial temporal lobe at 3T. The Automatic Segmentation of Hippocampal Subfields (ASHS) processing pipeline was used to extract CA1, CA2, CA3, dentate gyrus, and subiculum volumes. Partial correlations, controlling for age, sex, and intracranial volume, were performed to examine the association between subfield volumes, Frequency of Forgetting and California Verbal Learning Test (CVLT) immediate and long delayed recall scores. Frequency of Forgetting was correlated with left CA2 [r = .42, P =.003] and right subicular volume [r = .45, P =.001], while CVLT measures were not correlated with any hippocampal subfield volume. The associations between subicular volume, a region implicated in AD, and subjective, but not objective memory, suggests that self-perception of frequency of memory lapses in daily life may be sensitive to subtle, early AD-related volumetric changes within the hippocampus. The similar dissociation found for CA2, a region linked to social memory in animal models, is noteworthy.

Topic Area: METHODS: Neuroimaging