The screening accuracy and determination of optimal cutoff
point for dementia screening of the RUDAS-Thai and the
MMSE-Thai 2002 was summarized by the sensitivity, specificity,
predictive positive value, predictive negative value,
Yuden index, AUC, and likelihood ratio. Youden index was
used to determine an optimal cutoff point. The ROC curve was
used to summarize the overall accuracy of the RUDAS-Thai
and the MMSE-Thai 2002 for dementia detection. The AUC
was estimated for each screening tool separately, along with
their 95% CIs.
Regarding the cross-sectional sample in this study, it was
often difficult to distinguish very mild dementia from mild cognitive
impairment (MCI).22 To minimize the misclassification
bias, our analysis included only participants with normal cognition
and those with dementia.