The Dépistage Cognitif de Québec: A New Clinician's Tool for Early Recognition of Atypical Dementia.

Introduction: Early recognition of atypical dementia remains challenging partly because of lack of cognitive screening instruments precisely tailored for this purpose.

Methods: We assessed the validity and reliability of the Dépistage Cognitif de Québec (DCQ; www.dcqtest.org), a newly developed cognitive screening test, to detect atypical dementia using a multicenter cohort of 628 participants. Sensitivity and specificity were compared to the Montreal Cognitive Assessment (MoCA). A predictive diagnostic algorithm for atypical dementia was determined using classification tree analysis.

Results: The DCQ showed excellent psychometric properties. It was significantly more accurate than the MoCA to detect atypical dementia. All correlations between DCQ indexes and standard neuropsychological measures were significant. A statistical model distinguished typical from atypical dementia with a predictive power of 79%.

Discussion: The DCQ is a better tool to detect atypical dementia than standard cognitive screening tests. Expanding the clinician's tool kit with the DCQ could reduce missed/delayed identification of atypical dementia and accelerate therapeutic intervention.