The Clinical Utility of the Cognitive Impairment Screening Test (CIST)

The Cognitive Impairment Screening Test (CIST) was developed for use at the Community Dementia Reassurance Center in South Korea. This study evaluated convergent and discriminant validity of CIST, as well as its clinical utility in identifying cognitive impairment and differentiating amyloid deposition.

We enrolled 252 participants from a hospital memory clinic (47 cognitively unimpaired [CU], 116 amnestic mild cognitive impairment, and 89 dementia). Participants completed CIST, K-MMSE-2, the Seoul Neuropsychological Screening Battery, 2nd edition (SNSB-II), and underwent amyloid positron emission tomography. To evaluate the convergent and discriminant validity of CIST, we conducted correlation analyses with SNSB-II. Receiver operating characteristic analyses were used to evaluate the ability to discriminate cognitive impairment and to distinguish amyloid positivity. Areas under the curve (AUCs) for CIST and K-MMSE-2 were compared using DeLong's test.

The total score of CIST correlated significantly with all SNSB-II subtests, and the domain scores of CIST showed stronger associations with corresponding SNSB-II subtests than with unrelated ones. Both CIST and K-MMSE-2 effectively distinguished cognitively impaired individuals from CU, with CIST demonstrating superior discrimination (AUC=0.926 vs. 0.887, p=0.042). In the non-demented group, both CIST and K-MMSE-2 showed acceptable discrimination for amyloid positivity (AUC≈0.73), with high specificity but low sensitivity; however, there were no significant differences between the two tests.

The CIST demonstrated strong validity and discriminatory ability for detecting cognitive impairment. It also showed acceptable discrimination for amyloid positivity in non-demented participants, supporting its utility as a screening tool in both clinical and community settings.