Clock drawing test: comparison between the Pfizer and the Shulman systems.

Area of Science:

• Neurology
• Gerontology
• Cognitive Science

Background:

• Cognitive decline is a significant concern in aging populations.
• The clock drawing test (CDT) is a widely used screening tool for cognitive impairment.
• Several scoring systems exist for the CDT, including the Pfizer and Shulman methods.

Purpose of the Study:

• To analyze the correlation between two simple methods for scoring the clock drawing test (CDT).
• To evaluate the inter-observer and intra-observer concordance of the Pfizer and Shulman scoring systems.
• To assess the correlation of CDT scores with age and educational attainment.

Main Methods:

• A cross-sectional study involving 404 participants from the Elo-Creati cohort in Brazil.
• Two trained raters scored the CDT using both the Pfizer and Shulman systems.
• Spearman's rank correlation coefficient was used to analyze inter-observer and intra-observer concordance, as well as concordance between methods.

Main Results:

• High inter-observer and intra-observer concordance was found for both Pfizer and Shulman scoring systems.
• Significant correlation was observed between the Pfizer and Shulman methods.
• The Pfizer system classified a higher percentage of participants with decreased cognition compared to the Shulman system.
• Weak correlations were found between CDT scores and participants' age and educational attainment.

Conclusions:

• The Pfizer scoring system demonstrates higher suitability for screening cognitive decline in the studied population.
• Both scoring systems show good reliability, but the Pfizer method appears more sensitive in identifying cognitive impairment.
• Further research may explore the generalizability of these findings across diverse populations.