Comparison of Amyloid Positivity Rate and Accumulation Pattern between Amnestic and Non-Amnestic Type Mild Cognitive Impairment

Objective We aimed to compare cerebral beta-amyloid protein (A beta) positivity rate and amyloid accumulation pattern on amyloid positron emission tomography (PET) between mild cognitive impairment (MCI) subtypes, i.e. amnestic mild cognitive impairment (aMCI) and non-amnestic mild cognitive impairment (naMCI). Methods The study participants were 34 naMCI patients and age-, sex- and education-matched 68 aMCI patients (1:2 ratio) who visited the Dementia and Age-Associated Cognitive Decline Clinic of the Seoul National University Hospital. All participants received comprehensive clinical and neuropsychological assessments and [18F] florbetaben PET. Results A beta positivity rate of naMCI group (26.5%) was significantly lower than that of aMCI group (64.7%). Among A beta positive individuals, there was no difference in A beta accumulation pattern between naMCI and aMCI. Conclusion The findings suggest that MCI subtypes based on impaired cognitive domains have a differential association with brain A beta deposition, a core pathology of AD. Amnestic subtype of MCI are more closely associated with cerebral A beta deposition compared to nonamnestic subtype. In contrast, the pattern of amyloid deposition does not appear to have any difference between the subtypes.