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 (Aβ) 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 Aβ positivity rate of naMCI group (26.5%) was significantly lower than that of aMCI group (64.7%). Among Aβ positive individuals, there was no difference in Aβ accumulation pattern between naMCI and aMCI.Conclusion The findings suggest that MCI subtypes based on impaired cognitive domains have a differential association with brain Aβ deposition, a core pathology of AD. Amnestic subtype of MCI are more closely associated with cerebral Aβ deposition compared to nonamnestic subtype. In contrast, the pattern of amyloid deposition does not appear to have any difference between the subtypes.