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