Latent variables in cognitive decline: introducing a behavioral-relational factor.

INTRODUCTION

Latent variable analyses have been used to model the cognitive and functional (cf) decline associated with cognitive changes. The present study replicated and expanded upon this latent variable approach to include a second factor reflecting caregiver burden and behavioral and psychological symptoms of dementia (br).

METHODS

This study used ADNI data from 422 consented Wave 4 participants who had completed a MoCA, Functional Activity Questionnaire, Logical Memory II (delayed memory task), Trails Making Test - Part B, Neuropsychiatric Inventory, and Geriatric Depression Scale. Of the participants included in the analysis, 239 were considered cognitively normal, 110 had a diagnosis of MCI and 27 had a diagnosis of dementia.

RESULTS

Confirmatory factor analysis supported a two-factor model (CFI = .964; RMSEA = .091). All cognitive and functional measures loaded significantly on the cf factor (range: r = -.707 to .747; ps < .0001). All behavioral-relational measures loaded significantly on the br factor (range: r = .237 to .760; ps < .0001). Additionally, both latent variables were significantly associated with diagnosis type, such that cf declined and br increased with diagnosis severity.

DISCUSSION: This current study findings emphasize the importance of assessing cognitive performance from a whole-person perspective. Future research should focus on using these factors to predict dementia-related outcomes (e.g. nursing home placement, progression of decline).