Greater than the Sum of Its Parts: δ can be Constructed from Item Level Data

J Alzheimers Dis. 2016;49(2):571-9. doi: 10.3233/JAD-150250.


"δ", a latent variable constructed from cognitive performance and functional status measures, can accurately diagnose dementia. The minimal assessment needed is unknown. We have constructed a δ homolog, "dTEXAS", from Telephone Executive Assessment Scale (TEXAS) items, and validated it in a convenience sample of Japanese persons (n = 176). dTEXAS scores correlated strongly with both Instrumental Activities of Daily Living (IADL) (r = -0.86, p < 0.001) and Clinical Dementia Rating Scale (CDR) (r = 0.71, p < 0.001). Constructed independently of their diagnoses, dTEXAS scores accurately distinguished dementia versus controls (area under the receiver operating curve [(AUC; ROC) = 0.92], dementia versus mild cognitive impairment (MCI) (AUC = 0.80) and controls versus MCI (AUC = 0.74). These AUCs are higher than those of multiple observed executive measures, as reported recently by Matsuoka et al., 2014. A dTEXAS score of -0.58 best discriminated between dementia versus controls with 90.1% sensitivity and 80.0% specificity.

Keywords: CLOX; EXIT25; Instrumental Activities of Daily Living; dementia; executive function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living / psychology*
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / diagnosis*
  • Alzheimer Disease / psychology*
  • Cognitive Dysfunction / diagnosis*
  • Cognitive Dysfunction / psychology*
  • Executive Function / physiology*
  • Female
  • Humans
  • Japan
  • Male
  • Neuropsychological Tests
  • Psychiatric Status Rating Scales
  • ROC Curve
  • United States