Generational differences in clock drawing test performance.

Abstract

Objective: The clock drawing test is widely used in clinical neurological and neuropsychological assessment. We hypothesized that younger adults would have greater problems with clock drawing than older adults, perhaps due to decreasing analog clock use.

Methods: Cross-sectional study analyzing clock drawing performance and cognitive function across four generations (Gen Z, Millennials, Gen X, Baby Boomers). Participants included 92 adults divided into two generations (63 younger [18-42 years old] and 29 older [43-77 years old]) assessed between October 2022 and December 2024. Participants were screened to exclude conditions affecting cognition. The primary outcome was performance errors in clock drawing (e.g., writing "11:10" instead of drawing an analog clock, or placing hands incorrectly), assessed using standardized criteria. Cognitive function was assessed using eight computerized tests (CogState) measuring processing speed, attention, executive function, visuospatial memory, and verbal memory. Confirmatory factor analysis (CFA) validated three cognitive domain composites: Speed/Attention, Executive/Spatial, and Verbal Memory.

Results: Performance errors were significantly more prevalent among younger participants compared with older participants (p = .016; risk ratio, 4.45). The effect size was large (Cohen's h = .63). The generation effect was stronger (OR = 28.66, p = .003) after controlling for CFA-validated cognitive domain composites. This provides strong evidence that generational differences are independent of cognitive abilities.

Conclusions: Younger adults demonstrate significantly higher rates of clock drawing errors compared with older adults, independent of cognitive performance. These findings suggest a need for generation-specific or age adjusted norms in clock drawing test interpretation.