As the conceptual, methodological, and technological advances applied to dementias have evolved the construct of mild cognitive impairment (MCI), one problem encountered has been its classification into subtypes. Here, we aim to revise the concept of MCI and its subtypes, addressing the problems of classification not only from the psychometric point of view or by using alternative methods, such as latent class analysis, but also considering the absence of normative data. In addition to the well-known influence of certain factors on cognitive function, such as educational level and cultural traits, recent studies highlight the relevance of other factors that may significantly affect the genesis and evolution of MCI: subjective memory complaints, loneliness, social isolation, etc. The present work will contemplate the most relevant attempts to clarify the issue of MCI categorization and classification, combining our own data with that from recent studies which suggest the role of relevant psychosocial factors in MCI.

We applied latent class analysis (LCA) to a set of neuropsychological data with the aim of corroborating the three cognitive profiles of mild cognitive impairment (MCI) described in the literature, namely: healthy, amnestic, non-amnestic, and multidomain. The ultimate purpose of the LCA was to try to find the underlying classification of MCI and related pathologies by means of the participants’ response patterns, rather than on more classical psychometric criteria, such as the standard deviation of the mean. We computed 547 neuropsychological assessments derived from 223 participants who were assessed annually for three consecutive years. The battery included tests of memory, language, executive function, and praxis. The results obtained by means of LCA, with a four-group solution and using the 40th percentile as the criterion, confirm prior classifications obtained with more questionable psychometric criteria, while providing longitudinal data on the course of MCI and the stability of group assignment over time.