Combining the memory impairment screen and the isaacs set test: A practical tool for screening dementias

OBJECTIVES: To assess the accuracy of combining the Memory Impairment Screen (MIS) with the Isaacs Set Test (IST) in distinguishing subjects with dementia from controls without dementia. DESIGN: The weighted sum of MIS and IST scores was calculated, and the logical "or" rule combination was performed using two different patient and control samples. Combination results were compared with each test used alone and with Mini-Mental State Examination to detect all types of dementias. SETTING: Database of the Regional Network for Diagnostic Aid and Management of Patients with Cognitive Impairment in the Franche-Comte, France, geographical area. PARTICIPANTS: A cohort of 444 patients with Alzheimer's disease, non-Alzheimer's dementia, and reversible dementia and 311 controls. MEASUREMENTS: Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the combination of these two tests. RESULTS: The weighted sum had overall sensitivities of 0.92 and 0.84 for mild cases, with a specificity of 0.92. The "or" rule had overall sensitivities of 0.92 and 0.89 for mild cases, with a specificity of 0.90. This pairing requires no more than 5 minutes. Its scoring is simple with the "or" rule combination. CONCLUSION: The combination of MIS and IST could be a useful tool for screening dementias. The "or" rule combination seems particularly adapted to medical practice.