Mapping Cognitive Trajectories and Detecting Early Dementia Using the Mini-Mental State Examination Cognitive Charts: Application to the French Three-City Cohort

Abstract

The Cognitive Quotient (QuoCo) classification algorithm monitoring decline on age-and education-adjusted Mini-Mental State Examination (MMSE)-derived cognitive charts has proved superior to the conventionally-used cut-off for identifying incident dementia; however, it remains to be tested in different settings. Data were drawn from the Three-City Cohort to 1) assess the screening accuracy of the QuoCo, and 2) compare its performance to that of serial MMSE tests applying different cut-offs. For the QuoCo, sensitivity was 74.2 (95% CI: 71.4-76.8) and specificity 84.1 (83.6-84.7) and for the MMSE<24, 64.1 (61.1-67.0) and 94.8 (94.4-95.1), respectively; whereas overall accuracy and sensitivity was highest for MMSE cut-offs <25 and <26. User-friendly charts for mapping cognitive trajectories over visits with an alert for potentially 'abnormal' decline can be of practical use and encourage regular monitoring in primary care where the <24 cut-off is still widely used despite its poor sensitivity.