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

Article type: Research Article

Authors: Royall, Donald R.^{a; b; c; d; *} | Palmer, Raymond F.^c | Matsuoka, Teruyuki^e | Kato, Yuka^e | Taniguchi, Shogo^f | Ogawa, Mayu^e | Fujimoto, Hiroshi^e | Okamura, Aiko^g | Shibata, Keisuke^h | Nakamura, Kaeko^e | Nakaaki, Shutaroⁱ | Koumi, Hiroyuki^j | Mimura, Masaruⁱ | Fukui, Kenji^e | Narumoto, Jin^e

Affiliations: [a] Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA | [b] Department of Medicine, The University of Texas Health Science Center, San Antonio, TX, USA | [c] Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio, TX, USA | [d] South Texas Veterans’ Health System, Audie L. Murphy Division GRECC, San Antonio, TX, USA | [e] Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University School of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, Japan | [f] Reinan Hospital, Mikatakaminakagun, Wakasacho, Fukui, Japan | [g] Yashio Hospital, Yashio-shi, Saitama, Japan | [h] Kawagoe Hospital, Sakyo-ku, Kyoto, Japan | [i] Department of Neuropsychiatry, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan | [j] Department of Clinical Psychology, Faculty of Social Welfare, Hanazono University, Nishinokyo, Nakagyo-ku, Kyoto, Japan

Correspondence: [*] Correspondence to: Donald R. Royall, MD, Department of Psychiatry, The University of Texas Health Science Center, San Antonio, TX, USA. Tel.: +1 210 567 1255; E-mail: [email protected]

Abstract: “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, dementia, executive function, EXIT25, Instrumental Activities of Daily Living

DOI: 10.3233/JAD-150250

Journal: Journal of Alzheimer's Disease, vol. 49, no. 2, pp. 571-579, 2016