VITA: subtypes of mild cognitive impairment in a community-based cohort at the age of 75 years

Abstract

Background: Mild cognitive impairment (MCI) is defined to diagnose prodromal dementia and prodromal Alzheimer dementia, in particular.

Objective: The main aim of this study is to identify subtypes of MCI in comparison to the frequency of Petersen's MCI-amnestic in an elderly age-cohort.

Participants: The study is based on the cross sectional data from the Vienna-Transdanube-Aging (VITA) study. The data refer to the age cohort of 592 individuals at age 75 to 76 years who completed extensive neuropsychological examination.

Results: Dementia was present in 15 subjects (2.5%, CI: 1.4-4.1). 141 subjects (23.8%, CI: 20.4-27.5) of the entire age cohort 75 (n = 592) showed cognitive impairment without dementia concerning one or more cognitive functions (1.5 SD paradigm). These subjects were assigned to three subtypes of MCI: Selective Memory Impairment: n = 22 (3.7%, CI: 2.3-5.6), Memory Impairment+Non-Memory Impairment: n = 31 (5.2%, CI: 3.6-7.4) and Non-Memory Impairment: n = 88 (14.9%, CI: 12.1-18.0).

Conclusions: The frequency of MCI-amnestic, the so-called prestage of AD according to Petersen, was very low (0.5%, CI: 0.1-1.5) compared to the estimated incidence rates of AD at this age. Established criteria of MCI could be modified in order to include a higher percentage of high-risk subjects for later developing Alzheimer dementia.