Heterogeneity in Dementia and Mild Cognitive Impairment
Mild cognitive impairment (MCI) and dementia such as Alzheimer’s disease and vascular dementia are heterogeneous conditions that are associated with a chronic course and impairments across a multitude of neurobiological and neuropsychological domains. Until relatively recently, much research has relied on variable-centered techniques (e.g., structural equation modeling, factor analysis, regression) to delineate and study these conditions. This chapter presents evidence of the potential benefits of using person-centered procedures (e.g., latent class analysis) for identifying more homogeneous subgroups of individuals with MCI or dementia that may have distinct correlates, courses, and potential responses to interventions. The research reviewed in this chapter indicates that these strategies permit clinicians and investigators to (a) identify subgroups of individuals who differ in the frequency and/or quality of signs and symptoms, correlates, course, or outcomes, and (b) externally validate and provide support for the predictive validity of these subgroups. Steps for conducting latent class/profile analysis are presented, as well as indices used in selecting the best-fitting model. Implications for assessment, intervention, and future research are provided.