Estimating the Validity of the Korean Version of Expanded Clinical Dementia Rating (CDR) Scale

ABSTRACT

BACKGROUND: The Clinical Dementia Rating (CDR) scale is broadly accepted by clinicians as a staging measure for dementia. The aim of this study was to test inter-rater reliability and concurrent validity of the Korean version of the CDR. METHODS: Participants included 34 persons without dementia and 41 patients with Alzheimer's disease, and 37 patients with vascular dementia. The participants and their informed collateral sources were interviewed by a rater using a semistructured clinical interview. To obtain concurrent validity, all the participants received K-MMSE, K-SKT (Syndrom Kurz Test), and a 15-items abbreviated K-BNT on the same day. We also tested inter-rater reliability among four raters using a videotape design. RESULTS: Agreements of the overall CDR ratings (kappa, 0.86-1.0) and Sum of Boxes of CDR (CDR-SB) (gamma, 0.89-1.0) by the four raters were high. Both global CDR and CDR-SB correlated significantly with K-MMSE, K-SKT and the abbreviated K-BNT. The Orientation and Memory box score correlated significantly with orientation and memory scores of K-MMSE. CONCLUSIONS: The Korean version of CDR appears to be a reliable and valid tool as a staging measure for Korean dementia patients.