The Clock Drawing Test: A Valid Screening Instrument for Dementia Detection in Low-Educated Patients?

Area of Science:

• Neurology
• Geriatrics
• Cognitive Assessment

Background:

• The Clock Drawing Test (CDT) is a non-verbal cognitive screening tool.
• Its suitability for individuals with lower educational levels and language barriers is often assumed.
• This study investigates the validity of CDT in low-educated populations.

Purpose of the Study:

• To evaluate the Clock Drawing Test (CDT) as a screening instrument for low-educated patients.
• To perform a qualitative analysis of CDT errors in different educational groups.
• To determine optimal cutoff points for dementia screening using CDT.

Main Methods:

• 503 participants were categorized into dementia, MCI, no cognitive impairment, and other diagnosis groups.
• Participants were stratified by educational level: no, low, middle, and high education.
• The seven-point Freedman scoring system was used, with cutoff points <4 and <3 evaluated.

Main Results:

• Dementia groups consistently scored lower on CDT across all education levels, with the smallest difference in the no-education group.
• A CDT cutoff of <4 demonstrated higher sensitivity, especially for low-educated individuals.
• A CDT cutoff of <3 offered better specificity.
• Errors by low-educated non-dementia participants mirrored those of dementia patients.

Conclusions:

• The CDT, including total score and error analysis, has limited utility for dementia case-finding in low-educated populations.
• The CDT is most recommended for middle- and high-educated groups.
• Further research may be needed to identify suitable cognitive screening tools for low-educated individuals.