Checking the validity and reliability of the Japanese version of the Mini-Cog using a smartphone application

Objective Cognitive decline is an important and well-documented health problem. The Mini-Cog, a simple cognitive function test, is recommended as a potential early cognitive screening tool. Kanagawa Prefecture, one of the largest prefectures in Japan, developed this self-testing application on a smartphone to enable a large number of residents to assess their cognitive function. This study aimed to verify the validity and reliability of the Mini-Cog. Results Twenty men and 20 women aged 65–85 years were enrolled. Criterion-related validity of the method tested by professional staff was found to have an acceptable positive association. The test–retest reliability was lower than the clinically expected intraclass correlation coefficient value because of the inclusion of learning and order effects. If the Mini-Cog score of this application is low, the system is equipped with a function that advises the users on preventing cognitive decline, directing them to the appropriate services, and recommending visits to a medical institution. Therefore, the system can be used continuously as a tool for health behaviors and promotions.