Ic‐p‐117: Amyloid‐b Deposition in Mild Cognitive Impairment Is Associated With Hippocampal Hyperactivation, Atrophy, and Clinical Progression
Year: 2014
Type: article
Study design: Observational Study
Abstract: Hyperactive neurons may facilitate the deposition of amyloid-β and promote excitotoxic loss of neurons. A subset of older individuals with early mild cognitive impairment (MCI) demonstrate hippocampal hyperactivity, as measured by task-based functional magnetic resonance imaging (fMRI) and this has previously been linked to clinical progression of Alzheimer's disease (AD). Recent studies have demonstrated that MCI patients with elevated cortical amyloid-β (Aβ+) are also more likely to progress to AD dementia compared to MCI patients with low cortical amyloid-β (Aβ-). However, it remains unclear if hippocampal hyperactivation is associated with the presence of amyloid-β, rate of hippocampal atrophy and clinical progression. We followed a cohort of early MCI patients longitudinally for up to 3 years with fMRI, anatomical MRI and tracked clinical progression. PiB-PET amyloid imaging was used to identify Aβ- and Aβ+ MCI patients. Hippocampal fMRI activity was assessed using a face-name memory test. Hippocampal volume was quantified using 3T MP-RAGE sequence and the longitudinal FreeSurfer pipeline. Finally, clinical progression was assessed using the Clinical Dementia Rating sum of boxes (CDR-SB). At baseline, Aβ+ MCI patients showed hippocampal hyperactivation, smaller hippocampal volume, and scored worse on CDR sum of boxes compared to Aβ- MCI patients. Over time, Aβ+ MCI patients with higher levels of hippocampal activity at baseline demonstrated faster rates of hippocampal atrophy. Linear mixed effects models indicated that baseline estimates of amyloid-β were the strongest predictor of clinical decline followed by lower hippocampal volume and finally greater hippocampal activation.
Source: Alzheimer s & Dementia
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4250442452