Cognitive profiles in dementia

Abstract

Objective: To re-examine proposed models of cognitive test performance that concluded separate factor structures were required for people with Alzheimer disease (AD) and older adults without dementia.Methods: Five models of cognitive test performance were compared using multistep confirmatory factor analysis in 115 individuals with autopsy-confirmed AD and 191 research participants without clinical dementia from longitudinal studies at the Washington University AD Research Center. The models were then cross-validated using independent samples of 323 people with clinically diagnosed dementia of the Alzheimer type and 212 cognitively healthy older adults. Results:After controlling for Alzheimer-specific changes in episodic memory, performance on the battery of tests used here was best represented in people both with and without dementia by a single model of one general factor and three specific factors (verbal memory, visuospatial ability, and working memory). Performance by people with dementia was lower on the general factor than it was by those without dementia. Larger variances associated with the specific factors in the group with dementia indicated greater individual differences in the pattern of cognitive deficits in the stage of AD.Conclusions: A hybrid model of general and specific cognitive domains simplifies cognitive research by allowing direct comparison of normal aging and Alzheimer disease performance. The presence of a general factor maximizes detection of the dementia, whereas the specific factors reveal the heterogeneity of dementia's associated cognitive deficits. Neurology We previously reported that cognitive test performance in individuals with and without dementia is best characterized by two distinct factor structures: a single general factor for individuals without dementia compared with three orthogonal factors representing verbal memory, visuospatial, and working memory in dementia of the Alzheimer type (DAT).1 Other reports using similar exploratory techniques report separate factors (indicating that DAT affects different aspects of cognition independently 2-4 ), or a global deficit that produces a single general factor. 5,6 This discrepancy makes it difficult to know how best to compare and contrast decrements in cognitive performance between different patient populations.Confirmatory factor analysis (CFA) provides the ability to test competing models (i.e., general vs multiple factors) either within a single population or across multiple populations.

Longitudinal Changes in Cognition in Parkinson’s Disease with and without Dementia

“…This report extends previous work [8,9] characterizing cognitive ability in normal aging and Alzheimer’s disease (AD) to evaluate the cognitive course in PD with (PDD) and without dementia (PDND). First, we determined whether a factor analytic model of general and domain-specific cognitive abilities empirically derived in people with and without AD applied to PDD and PDND.…”

“…There were no sex or race restrictions. Data from the autopsy-confirmed AD (n = 115) and healthy aging (n = 191) groups have been previously reported [8] and are included here as reference groups for a comparison with the PD groups. Individuals with disorders that can result in other types of dementia or parkinsonism [e.g.…”

“…semantic memory, episodic memory, working memory, and visuospatial ability) across multiple cognitive domains which were previously described in detail [8]. It was administered annually to all participants approximately 2 weeks after clinical evaluation.…”

P4–059: Amyloid imaging and CSF biomarkers in predicting cognitive impairment up to 7.5 years later

“…Similar analyses were conducted for a global composite psychometric score, 22 which was available for a subset of participants who had the same psychometric test battery. The linear mixed models were adjusted for the same demographic variables selected by the stepwise procedure in the expanded Cox proportional hazards model containing the biomarker of interest.…”

Effect of cognitive fluctuation on neuropsychological performance in aging and dementia

“…Based on confirmatory factor analyses of these measures that were cross-validated across samples with and without dementia 24 and subsequent work including more measures, we also report 5 composite scores for each person at time of assessment. The episodic memory composite included Logical Memory, Associate Learning, and free recall from the SRT.…”