Background: The accuracy and harms of brief cognitive tests for identifying clinical Alzheimer-type dementia (CATD) are uncertain. Purpose: To summarize evidence on accuracy and harms of brief cognitive tests for CATD in older adults with suspected cognitive impairment. Data Sources: Electronic bibliographic databases (from inception to November 2019) and systematic review bibliographies. Study Selection: English-language, controlled observational studies in older adults that evaluated the accuracy of brief cognitive tests (standalone tests; memory, executive function, and language tests; and brief multidomain batteries) for distinguishing CATD from mild cognitive impairment (MCI) or normal cognition as defined by established diagnostic criteria. Studies with low or medium risk of bias (ROB) were analyzed. Data Extraction: Two reviewers rated ROB. One reviewer extracted data; the other verified extraction accuracy. Data Synthesis: Fifty-seven studies met analysis criteria. Many brief, single cognitive tests were highly sensitive and specific for distinguishing CATD from normal cognition. These included standalone tests (clock-drawing test, median sensitivity 0.79 and specificity 0.88 [8 studies]; Mini-Mental State Examination, 0.88 and 0.94 [7 studies]; Montreal Cognitive Assessment, 0.94 and 0.94 [2 studies]; and Brief Alzheimer Screen, 0.92 and 0.97 [1 study]), memory tests (list delayed recall, 0.89 and 0.94 [5 studies]), and language tests (category fluency, 0.92 and 0.89 [9 studies]). Accuracy was lower in distinguishing mild CATD from normal cognition and distinguishing CATD from MCI. No studies reported on testing harms. Limitations: Studies were small. Few test metrics were evaluated by multiple studies. Few studies directly compared different tests, scores, cut points, or test combinations. Conclusion: Many brief, single cognitive tests accurately distinguish CATD from normal cognition in older adults but are less accurate in distinguishing mild CATD from normal cognition or CATD from MCI. No studies reported on testing harms.
Bibliographical noteFunding Information:
Disclaimer: This article is based on research conducted by the Minnesota Evidence-based Practice Center under contract to AHRQ, Rockville, Maryland (contract HHSA 290-2015-00008-I). The findings and conclusions in this document are those of the authors, who are responsible for its contents; the findings and conclusions do not necessarily represent the views of AHRQ. Therefore, no statement in this report should be construed as an official position of AHRQ or the U.S. Department of Health and Human Services. The AHRQ retains a license to display, reproduce, and distribute the data and the report from which this manuscript was derived under the terms of the agency's contract with the author.
This review was funded by the Agency for Healthcare Research and Quality (AHRQ). Agency staff and a key informant panel helped refine the project scope. The draft report was reviewed by a technical expert panel, peer and public reviewers, and AHRQ staff. The authors are solely responsible for the content of this article.
© 2020 American College of Physicians. All rights reserved.