Self-Reported Cognitive Decline Based on the Ascertain Dementia 8 Questionnaire May Be Effective for Detecting Mild Cognitive Impairment and Dementia in the Community: The Wakuya Project

Introduction: To assess cognitive impairment, self-awareness is an important issue. The Ascertain Dementia 8 questionnaire (AD8) is a brief observation checklist for detecting mild cognitive impairment (MCI) and dementia. After analyzing the reliability and validity of a self-reported Japanese version of the AD8 (AD8-J), we compared self-and informant-reported versions of the AD8-J. Methods: A total of 93 community residents aged 75 years or older living in Wakuya, Northern Japan, agreed to participate in this study; 35 were rated as Clinical Dementia Rating (CDR) 0 (healthy), 46 as CDR 0.5 (defined herein as MCI), and 12 as CDR 1 or above (dementia, confirmed by the DSM-IV). We examined the reliability and validity using a receiver operating characteristic (ROC) curve. We analyzed the differences between self-reported and informant-reported AD8-J using a repeated measures ANOVA. Results: The self-reported AD8-J showed a satisfactory reliability (i.e., Cronbach coefficient, α = 0.71; Guttman split half method coefficient = 0.60). For CDR 0 vs. CDR 0.5 or above, the area under the ROC curve was 0.74 and the cutoff score was 1/2, with a sensitivity of 70.7% and a specificity of 65.7%. Analysis of the subscores of AD8 suggested that, from the early stage of dementia, the subjects showed a subjective decline in memory and interest in hobbies/activities, as well as problems with judgment. Conclusion: It is suggested that the self-reported AD8-J was effective in detecting MCI and dementia. We could use it for detecting MCI and dementia, including in those living alone, in the primary health checkup.