Test accuracy of cognitive screening tests for diagnosis of dementia and multidomain cognitive impairment in stroke
Lees R., Selvarajah J., Fenton C., Pendlebury ST., Langhorne P., Stott DJ., Quinn TJ.
BACKGROUND AND PURPOSE: Guidelines recommend screening stroke-survivors for cognitive impairments. We sought to collate published data on test accuracy of cognitive screening tools. METHODS: Index test was any direct, cognitive screening assessment compared against reference standard diagnosis of (undifferentiated) multidomain cognitive impairment/dementia. We used a sensitive search statement to search multiple, cross-disciplinary databases from inception to January 2014. Titles, abstracts, and articles were screened by independent researchers. We described risk of bias using Quality Assessment of Diagnostic Accuracy Studies tool and reporting quality using Standards for Reporting of Diagnostic Accuracy guidance. Where data allowed, we pooled test accuracy using bivariate methods. RESULTS: From 19 182 titles, we reviewed 241 articles, 35 suitable for inclusion. There was substantial heterogeneity: 25 differing screening tests; differing stroke settings (acute stroke, n=11 articles), and reference standards used (neuropsychological battery, n=21 articles). One article was graded low risk of bias; common issues were case-control methodology (n=7 articles) and missing data (n=22). We pooled data for 4 tests at various screen positive thresholds: Addenbrooke's Cognitive Examination-Revised ( < 88/100): sensitivity 0.96, specificity 0.70 (2 studies); Mini Mental State Examination ( < 27/30): sensitivity 0.71, specificity 0.85 (12 studies); Montreal Cognitive Assessment ( < 26/30): sensitivity 0.95, specificity 0.45 (4 studies); MoCA ( < 22/30): sensitivity 0.84, specificity 0.78 (6 studies); Rotterdam-CAMCOG ( < 33/49): sensitivity 0.57, specificity 0.92 (2 studies). CONCLUSIONS: Commonly used cognitive screening tools have similar accuracy for detection of dementia/multidomain impairment with no clearly superior test and no evidence that screening tools with longer administration times perform better. MoCA at usual threshold offers short assessment time with high sensitivity but at cost of specificity; adapted cutoffs have improved specificity without sacrificing sensitivity. Our results must be interpreted in the context of modest study numbers: heterogeneity and potential bias.