The δ Latent Dementia Phenotype in the Uniform Data Set: Cross-Validation and Extension

• Published in: Neuropsychology Vol. 29; no. 3; pp. 344 - 352
• Main Authors: Gavett, Brandon E., Vudy, Vanessa, Jeffrey, Mary, John, Samantha E., Gurnani, Ashita S., Adams, Jason W.
• Format: Journal Article
• Language: English
• Published: United States American Psychological Association 01-05-2015
• Subjects: Ability Level; Activities of Daily Living; Aged; Aged, 80 and over; Alzheimer Disease - psychology; Cognition - physiology; Dementia; Dementia - psychology; Factor Analysis; Factor Analysis, Statistical; Female; Human; Humans; Male; Middle Aged; Phenotype; Phenotypes; Statistical Validity; factor analysis; dementia; statistical; validation studies; activities of daily living; longitudinal studies
• ISSN: 0894-4105; 1931-1559
• DOI: 10.1037/neu0000128

Objective: Royall and colleagues identified a latent dementia phenotype, "δ", reflecting the "cognitive correlates of functional status." We sought to cross-validate and extend these findings in a large clinical case series of adults with and without dementia. Method: A confirmatory factor analysis (CFA) model for δ was fit to National Alzheimer's Coordinating Center data (n = 26,068). Factor scores derived from δ were compared with the Clinical Dementia Rating Sum of Boxes (CDR-SB) and to clinically diagnosed dementia. A longitudinal parallel-process growth model compared changes in δ with changes in CDR-SB over 6 annual evaluations. Results: The CFA model fit well; CFI = 0.971, RMSEA = 0.070. Factor scores derived from δ discriminated between demented and nondemented participants with an area under the curve of .96. The growth model also fit well, CFI = 0.969, RMSEA = 0.032. Conclusions: The δ construct represents a novel approach to measuring dementia-related changes and has potential to improve cognitive assessment of neurodegenerative diseases.