Reliability and validity of the Japanese version of the AD8

Objective: The AD8 is a brief, sensitive informant interview tool for detecting dementia. However, there are no reports of a Japanese version of the AD8. Our aim was to establish the reliability and validity of the AD8 for screening for dementia in older adults 75 years of age or older in Japan.

Methods: We acquired the author's permission to translate the AD8 from English to Japanese. A total of 572 community residents 75 years of age or older living in Kurihara, Northern Japan agreed to participate in this study. Of these participants, 214 scored a Clinical Dementia Rating (CDR) of 0 (healthy), 289 scored a CDR of 0.5 (mild cognitive impairment) and 69 scored a CDR of 1 or above (dementia). Analysis 1. Reliability of the Japanese version of the AD8. Analysis 2. Validity of the AD8: Receiver operating characteristic (ROC) curve for nondemented (CDR 0+0.5) vs. demented (CDR 1 or above) individuals.

Results: For the Japanese version of the AD8, the Cronbach' s coefficient alpha was 0.88 and the Guttman's split half method coefficient was 0.85. For the patients with CDR values of 0+0.5 vs. 1 or above, the area under the ROC curve was 0.89 (p<0.0001) and the cut-off score was 1/2, with a sensitivity of 88.4% and specificity of 68.4%.

Conclusions: We established the reliability and validity of the Japanese version of the AD8 for screening for dementia in older adults 75 years of age or older in the community.