Understated Cognitive Impairment Assessed with the Clock-Drawing Test in Community-Dwelling Individuals Aged ≥50 Years

Objectives: To estimate the prevalence of understated cognitive impairment by administering the Clock-Drawing Test (CDT) to community-dwelling individuals aged ≥50 years and to investigate the associated clinical phenotype.

Design: A cross-sectional analysis of baseline data on community-dwelling individuals assessed at an outpatient clinic in the Paris region of France.

Setting and participants: Participants aged ≥50 years (n = 488, median age: 62.1 years) prospectively included in the SUCCessful agEing outpatiEnt's Department survey between 2010 and 2014.

Methods: A multidimensional geriatric assessment, including cognition [7-point CDT, Mini-Mental State Examination (MMSE), the 5-word screening test (5-WT), and the Frontal Assessment Battery (FAB)], gait speed in dual tasks, mood [the Geriatric Depression Scale (GDS)], balance, physical functions (gait speed and handgrip strength), nutrition, bone density, and comorbidities; major cardiovascular risk factors, and Scheltens and Fazekas scores on brain magnetic resonance imaging. Baseline characteristics were analyzed as a function of the CDT score (<7 vs 7), using age-adjusted logistic models.

Results: The prevalence of impairment in the CDT was 23.6%; higher than the values for the MMSE (12.7%), 5-WT (2.3%), and FAB (16.6%). In age-adjusted analyses, a lower educational level (odds ratio [95% confidence interval] = 0.72 [0.58‒0.89]), diabetes (2.57 [1.14‒5.79]), metabolic syndrome (1.93 [1.05‒3.56]), lower gait speed in the cognitive dual task (1.27 [1.05‒1.53]), a poorer Geriatric Depression Scale score (1.86 [1.04‒3.32]), a poorer MMSE score (2.56 [1.35‒4.88]), a poorer FAB score (1.79 [1.01‒3.16]), impaired episodic memory in the 5-WT (4.11 [1.12‒15.02]), and a higher Scheltens score (P = .001) were significantly associated with CDT impairment.

Conclusions and implications: Understated cognitive impairment is common among young seniors and is associated with factors known to be linked to a higher risk of cognitive decline and dementia. These findings suggest that the CDT may be of value for identifying high-risk individuals who may then benefit from targeted multidomain prevention actions (diet, exercise, cognitive training, and vascular risk factor management).