Consequences of age and education correction of cognitive screening tests - A simulation study of the MoCA test in Italy.

Background: Cognitive screening tools are widely used in clinical practice to screen for age-related cognitive impairment and dementia. These tools' test scores are known to be influenced by age and education, leading to routine correction of raw scores for these factors. Despite these corrections being common practice, there is evidence suggesting that corrected scores may perform worse in terms of discrimination than raw scores.
Objective: To address the ongoing debate in the field of dementia research, we assessed the impact of the corrections on discrimination, specificity, and sensitivity of the Montreal Cognitive Assessment test in Italy, both for the overall population and across age and education strata.
Methodology: We created a realistic model of the resident population in Italy in terms of age, education, cognitive impairment and test scores, and performed a simulation study.
Results: We confirmed that the discrimination performance was higher for raw scores than for corrected scores in discriminating patients with cognitive impairment from individuals without (areas under the curve of 0.947 and 0.923 respectively). With thresholds determined on the overall population, raw scores showed higher sensitivities for higher-risk age-education groups and higher specificities for lower-risk groups. Conversely, corrected scores showed uniform sensitivity and specificity across demographic strata, and thus better performance for certain age-education groups.
Conclusion: Raw and corrected scores show different performances due to the underlying causal relationships between the variables. Each approach has advantages and disadvantages, the optimal choice between raw and corrected scores depends on the aims and preferences of practitioners and policymakers.
Competing Interests: Declarations Competing interests Hans-Aloys Wischmann worked for Philips in various healthcare research and innovation management roles, up to April 2021. Outside of the submitted work, Giancarlo Logroscino reports having received speaking honoraria from Lilly, GE Healthcare, Lundbeck and being an associate editor of Neuroepidemiology/Karger. Outside of the submitted work, Tobias Kurth reports receiving research grants from the Gemeinsamer Bundesausschuss (G-BA Federal Joint Committee, Germany) and the Bundesministerium für Gesundheit (BMG—Federal Ministry of Health, Germany). He further reports having received personal compensation from Eli Lilly and Company, Novartis, the BMJ, and Frontiers. Marco Piccininni reports having received partial funding from Novartis Pharma and being awarded a research grant from the Center for Stroke Research Berlin (private donations), both outside of the submitted work. Ethical approval and Informed consent Ethical approval was not required for this research as all analyzed data were simulated based on publicly available statistics, and no human participants were involved.
(© 2024. The Author(s).)