APP and dementia: Three goals were achieved in this study: (1) MCAT was verified as 20.19% (= [53 − 42.3]/53) more efficient for answering questions and achieved similar precision in measurements to that of NAT; (2) a set of cut-off points was determined at − 1.4, − 0.4, 0.4, and 1.4, which can be used for reporting the extent of dementia for patients through the process of MCAT; (3) the online MCAT dementia APP for patients’ family members is confirmed to be suitable for smartphones; and the results are directly shown on Google Maps (Fig. 5), a feature that is rarely seen in previously published papers.