Introduction: The increasing use of Alzheimer's disease (AD) biomarkers has led to the recognition of a subgroup of non-AD amnestic mild cognitive impairment (aMCI) patients who have medial temporal hypometabolism on fluorodeoxyglucose-positron emission tomography (FDG-PET).
Methods: In this academic memory-clinic-based consecutive series, 16 non-AD aMCI patients and 28 AD controls matched for sex, age, and baseline Mini-Mental State Examination (MMSE) were followed for a median duration of 4.5 years. Our primary outcome was the MMSE decline rate over the subsequent years. We also determined the final diagnosis over time.
Results: FDG-PET showed more pronounced medial temporal hypometabolism in non-AD cases and more inferior parietal lobule hypometabolism in AD controls. MMSE decline was slower in non-AD (β = -0.51) than in AD (β = -2.00) patients. Five non-AD cases developed frontotemporal dementia years after symptom onset, and one developed dementia with Lewy bodies.
Discussion: Non-AD aMCI patients with medial temporal hypometabolism show slower cognitive decline.
Highlights: Non-AD aMCI with medial temporal hypometabolism shows slower cognitive decline than AD.FDG-PET revealed distinct metabolic patterns between non-AD aMCI and AD patients.Approximately one-third of non-AD aMCI cases developed frontotemporal dementia.Comprehensive diagnostic biomarkers are crucial for non-AD aMCI characterization.
Keywords: amyloid biomarkers; cognitive decline; dementia with Lewy bodies (DLB); frontotemporal dementia (FTD); medial temporal hypometabolism; neurodegenerative diseases; neuropsychological assessment; non‐AD amnestic mild cognitive impairment (non‐AD aMCI).
© 2024 The Author(s). Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals LLC on behalf of Alzheimer's Association.