Clock drawing in the Montreal Cognitive Assessment: recommendations for dementia assessment

Abstract

Background: Clock drawing is part of the Montreal Cognitive Assessment (MoCA) test but may have administration and scoring limitations. We assessed (1) the reliability of the MoCA clock criteria relative to a published error scoring approach, (2) whether command-only administration could distinguish dementia from cognitively intact individuals and (3) the value of adding a clock copy condition to the MoCA.

Methods: Three novice raters and clocks from dementia and control participants were used to assess the 3 aims.

Results: MoCA interrater and intrarater reliability were low (i.e. intraclass correlation coefficient = 0.12-0.31) and required repeat training. Clocks drawn to command classified dementia at chance. Inclusion of a copy condition demonstrated expected dementia subgroup patterns.

Conclusion: Reliable clock scoring with MoCA criteria requires practice. Supplementing a clock copy to the standard MoCA test (takes <1 min) will improve dementia assessment.