Accuracy of the short-form Montreal Cognitive Assessment: Systematic review and validation

INTRODUCTION: Short-form versions of the Montreal Cognitive Assessment (SF-MoCA) are increasingly used to screen for dementia in research and practice. We sought to collate evidence on the accuracy of SF-MoCAs and to externally validate these assessment tools. METHODS: We performed systematic literature searching across multidisciplinary electronic literature databases, collating information on the content and accuracy of all published SF-MoCAs. We then validated all the SF-MoCAs against clinical diagnosis using independent stroke (n = 787) and memory clinic (n = 410) data sets. RESULTS: We identified 13 different SF-MoCAs (21 studies, n = 6477 participants) with differing test content and properties. There was a pattern of high sensitivity across the range of SF-MoCA tests. In the published literature, for detection of post stroke cognitive impairment, median sensitivity across included studies: 0.88 (range: 0.70-1.00); specificity: 0.70 (0.39-0.92). In our independent validation using stroke data, median sensitivity: 0.99 (0.80-1.00); specificity: 0.40 (0.14-0.87). To detect dementia in older adults, median sensitivity: 0.88 (0.62-0.98); median specificity: 0.87 (0.07-0.98) in the literature and median sensitivity: 0.96 (range: 0.72-1.00); median specificity: 0.36 (0.14-0.86) in our validation. Horton's SF-MoCA (delayed recall, serial subtraction, and orientation) had the most favorable properties in stroke (sensitivity: 0.90, specificity: 0.87, positive predictive value [PPV]: 0.55, and negative predictive value [NPV]: 0.93), whereas Cecato's "MoCA reduced" (clock draw, animal naming, delayed recall, and orientation) performed better in the memory clinic (sensitivity: 0.72, specificity: 0.86, PPV: 0.55, and NPV: 0.93). CONCLUSIONS: There are many published SF-MoCAs. Clinicians and researchers using a SF-MoCA should be explicit about the content. For all SF-MoCA, sensitivity is high and similar to the full scale suggesting potential utility as an initial cognitive screening tool. However, choice of SF-MoCA should be informed by the clinical population to be studied.