Exploring the validity of mild cognitive impairment (MCI) subtypes: Multiple-domain amnestic MCI is the only identifiable subtype at longitudinal follow-up

Abstract

BACKGROUND: Epidemiological research exploring risk factors for Alzheimer's dementia resulted in the identification of the mild cognitive impairment (MCI) profile. Subsequently, distinct subtypes of MCI have been proposed; however, the validity of these as diagnostic entities remains uncertain. DESIGN AND PARTICIPANTS: The aim of the present study was to examine the longitudinal neuropsychological profiles of MCI subtypes. A total of 118 adults aged 60-90 years were classified at screening as amnestic (a-MCI), nonamnestic (na-MCI), and multiple-domain amnestic (a-MCI+) and were assessed at two time points across 20 months on a comprehensive neuropsychological assessment battery. RESULTS: The a-MCI+ group displayed the poorest performance of all groups in terms of episodic memory, working memory, attention, and executive functioning. CONCLUSIONS: These findings suggest that the a-MCI+ subtype is the only variant that is recognizable via neuropsychological testing. In contrast, the differentiation between single-domain subtypes and healthy controls is difficult and may not be achievable through current neuropsychological assessment practices.