title: A MULTIVARIATE FINITE MIXTURE LATENT TRAJECTORY MODEL WITH APPLICATION TO DEMENTIA STUDIES.
abstract: Dementia patients exhibit considerable heterogeneity in individual trajectories of cognitive decline, with some patients showing rapid decline following diagnoses while others exhibiting slower decline or remaining stable for several years. Dementia studies often collect longitudinal measures of multiple neuropsychological tests aimed to measure patients' decline across a number of cognitive domains. We propose a multivariate finite mixture latent trajectory model to identify distinct longitudinal patterns of cognitive decline simultaneously in multiple cognitive domains, each of which is measured by multiple neuropsychological tests. EM algorithm is used for parameter estimation and posterior probabilities are used to predict latent class membership. We present results of a simulation study demonstrating adequate performance of our proposed approach and apply our model to the Uniform Data Set (UDS) from the National Alzheimer's Coordinating Center (NACC) to identify cognitive decline patterns among dementia patients.
authors.affiliation: Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Dongbing
authors.initials: D
authors.lastname: Lai
authors.affiliation: Department of Biostatistics, Indiana University School of Public Health and School of Medicine, Indianapolis, Indiana.
authors.forename: Huiping
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Daniel
authors.initials: D
authors.lastname: Koller
authors.affiliation: Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Foroud
authors.affiliation: Department of Biostatistics, Indiana University School of Public Health and School of Medicine, Indianapolis, Indiana.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Gao
keywords: Multivariate finite mixture latent trajectory; cognitive decline; dementia