title: Greater than the sum of its parts: δ Improves upon a battery's diagnostic performance.
abstract: OBJECTIVE
  "δ", a latent variable constructed from batteries that contain both cognitive and functional status measures, can accurately diagnose dementia relative to expert clinicians. The minimal assessment needed is unknown.
  
  
  METHODS
  We validated 2 δ homologs in a convenience sample of elderly Japanese persons with normal cognition (NC), mild cognitive impairment (MCI), and dementia (n = 176). The latent δ homolog "d" (for dementia) was constructed from Instrumental Activities of Daily Living (IADL) and Japanese translations of the Executive Clock-Drawing Task (CLOX), Frontal Assessment Battery (FAB), and Executive Interview (EXIT25). The latent delta homolog "d3" was constructed from a restricted set of d's factor loadings.
  
  
  RESULTS
  d and d3 were highly intercorrelated (r = .97) and strongly related to both IADL and dementia severity, as rated blindly by the Clinical Dementia Rating Scale (CDR). d was more strongly related to IADL and CDR than any of its indicators. In multivariate regression, d explained more variance in CDR scores than all of its indicators combined. d's areas under the receiver operating characteristic curve (AUC) were 0.95 for the discrimination between Alzheimer's disease (AD) vs. NC, 0.84 for AD vs. MCI and 0.81 for NC vs. MCI. d3's AUC's were statistically indiscriminable. These AUC's are higher than any of d's indicators, as reported recently by Matsuoka et al. (2014), as well as the Mini-Mental State Examination (MMSE), which had been made available by Matsuoka et al. to the CDR raters.
  
  
  CONCLUSIONS
  Latent variables can improve upon a battery's diagnostic performance and offer the potential for accurate dementia case-finding after a minimal bedside assessment.
authors: Department of Psychiatry, University of Texas Health Science Center at San Antonio.
authors: Donald R
authors: DR
authors: Royall
authors: Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.
authors: Teruyuki
authors: T
authors: Matsuoka
authors: Department of Family and Community Medicine, University of Texas Health Science Center at San Antonio.
authors: Raymond F
authors: RF
authors: Palmer
authors: Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.
authors: Yuka
authors: Y
authors: Kato
authors: Reinan Hospital.
authors: Shogo
authors: S
authors: Taniguchi
authors: Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.
authors: Mayu
authors: M
authors: Ogawa
authors: Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.
authors: Hiroshi
authors: H
authors: Fujimoto
authors: Yashio Hospital.
authors: Aiko
authors: A
authors: Okamura
authors: Kawagoe Hospital.
authors: Keisuke
authors: K
authors: Shibata
authors: Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.
authors: Kaeko
authors: K
authors: Nakamura
authors: Department of Neuropsychiatry, Keio University School of Medicine.
authors: Shutaro
authors: S
authors: Nakaaki
authors: Department of Clinical Psychology, Faculty of Social Welfare, Hanazono University.
authors: Hiroyuki
authors: H
authors: Koumi
authors: Department of Neuropsychiatry, Keio University School of Medicine.
authors: Masaru
authors: M
authors: Mimura
authors: Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.
authors: Kenji
authors: K
authors: Fukui
authors: Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.
authors: Jin
authors: J
authors: Narumoto
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000523:psychology; D019540:Area Under Curve; D044466:Asian People; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology*; D060825:Cognitive Dysfunction / Q000523:psychology; D003627:Data Interpretation, Statistical; D003704:Dementia / Q000523:psychology; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D012372:ROC Curve