P194: A comparison study between AD8 and modified AD8 for dementia screening

Abstract

Objective:

The 8-item Informant Interview to Differentiate Aging and Dementia (AD8) was developed as a screening tool for dementia with a cutoff of 2 suggested by the initial study. However, various studies found different cutoff values, and many suggested a cutoff of 2 might result in a high false positive rate. A higher false positive rate in Taiwan was repeatedly shown when AD8 was self-administered in local government screening programs. We have developed a modified version of AD8 (m-AD8) with the purpose of enhancing its specificity. This study aimed to compare the performance of AD8 and m-AD8.

Methods:

The m-AD8 consists of all items adapted from the original AD8. Modifications included: (1) limiting the evaluated period to the past year instead of the past several years, (2) reselecting examples to reflect the socio-cultural context in Taiwan, and (3) rearranging the order of questions according to their complexity. We recruited 118 participant-informant dyads from a university teaching hospital. For each informant, the AD8 was administered first and then the Clinical Dementia Rating (CDR) to minimize contamination effect. The m-AD8 was administered 7 days later. Two geriatric psychiatrists made the final consensus DSM-5 diagnosis for each subject after considering all clinical information, including history, Mini-Mental State Examination (MMSE), CDR, and, if available, other past neuropsychological tests and neuroimaging.

Results:

There were 59 subjects with normal cognition, 28 with mild neurocognitive disorder, and 31 with dementia (major neurocognitive disorder). When comparing dementia vs. non-dementia, the optimal cutoff value was 4 for both versions according to the Youden index. The AUC, sensitivity, and specificity were 0.893, 0.774, 0.862 for AD8, and 0.883, 0.741, 0.954 for m-AD8, respectively. The m-AD8 showed improved specificity, which was also true when the cutoff value was set as 2 or 3.

Conclusion:

The optimal cutoff value for both versions was 4. The modification may change the performance of AD8 with improved specificity. These findings suggest that, depending on different situations, AD8 with a cutoff value higher than 2 may perform better in dementia screening.