Cognitive screening instruments for dementia: comparing metrics of test limitation

Abstract

Cognitive screening instruments (CSIs) for dementia and mild cognitive impairment are usually characterized in terms of measures of discrimination such as sensitivity, specificity, and likelihood ratios, but these CSIs also have limitations. Objective: The aim of this study was to calculate various measures of test limitation for commonly used CSIs, namely, misclassification rate (MR), net harm/net benefit ratio (H/B), and the likelihood to be diagnosed or misdiagnosed (LDM). Methods: Data from several previously reported pragmatic test accuracy studies of CSIs (Mini-Mental State Examination, the Montreal Cognitive Assessment, Mini-Addenbrooke’s Cognitive Examination, Six-item Cognitive Impairment Test, informant Ascertain Dementia 8, Test Your Memory test, and Free-Cog) undertaken in a single clinic were reanalyzed to calculate and compare MR, H/B, and the LDM for each test. Results: Some CSIs with very high sensitivity but low specificity for dementia fared poorly on measures of limitation, with high MRs, low H/B, and low LDM; some had likelihoods favoring misdiagnosis over diagnosis. Tests with a better balance of sensitivity and specificity fared better on measures of limitation. Conclusions: When deciding which CSI to administer, measures of test limitation as well as measures of test discrimination should be considered. Identification of CSIs with high MR, low H/B, and low LDM, may have implications for their use in clinical practice.

Cognitive status and dental‐related function in older adults seeking community‐based dental care: A Pilot Study

“…The difference may come from the criteria used to identify participants with cognitive impairment, such as family report versus self‐complaints, other neurological assessment, or neurologist evaluation. In addition, the cognitive assessment used in our study, MoCA, has been reported to have higher sensitivity than the other screening tools included in the meta‐analysis, which also helps explain the high prevalence of cognitive impairment in the study participants 15,16 . Another possible explanation is that patients visiting dental school clinics tend to be of lower socioeconomic status, 17 which has been reported to have an association with cognitive impairment 18 …”

“…In addition, the cognitive assessment used in our study, MoCA, has been reported to have higher sensitivity than the other screening tools included in the meta-analysis, which also helps explain the high prevalence of cognitive impairment in the study participants. 15,16 Another possible explanation is that patients visiting dental school clinics tend to be of lower socioeconomic status, 17 which has been reported to have an association with cognitive impairment. 18 The proportion of impaired DRF (13.8%) in our sample is difficult to compare to previous studies, as they focused on assisted living residents.…”

Cognitive Screening in Older People Using Free-Cog and Mini-Addenbrooke’s Cognitive Examination (MACE)

“…This outcome might possibly reflect the hybrid nature of Free-Cog as a test of both cognitive and executive functions, since other studies have suggested such a combination may improve detection of neurocognitive disorder [20], although fragmenting the Free-Cog into separate tests of cognitive and executive functions did not suggest better overall performance than the unitary Free-Cog [16]. Other analyses of Free-Cog have previously shown that it fares well in comparison to other short cognitive screening instruments in so-called "metrics of limitation" such as misclassification rate and net harm/net benefit ratio [21].…”

Free-Cog reformulated: analyses as independent or stepwise tests of cognitive and executive function

“…10,11 Initial studies have suggested that Free-Cog is an acceptable and efficacious instrument for the identification of cognitive impairment, 10,12 whose metrics compare favourably with other brief cognitive screening instruments. 10,12,13 Free-Cog is available free of copyright in both standard and abridged forms suitable respectively for face-to-face 10 and remote (telephone, video) 10,14 testing.…”