Clock Drawing Test [CDT-1]

Purpose

The Clock Drawing Test (CDT) is a simple yet powerful tool for assessing executive function, general cognitive status, and visuospatial perception. It is mainly used in individuals suspected of having neurological or psychiatric disorders, such as Alzheimer’s-type dementia, traumatic brain injuries, and memory disorders.

Brief Description

The examinee is asked to draw an analog clock, correctly placing the circle, the numbers, and the hands so that they indicate a specific time, for example “10:10”. Through this process, spatial and temporal organization, perception, as well as the ability for detailed representation and executive control are evaluated.

Scoring

Scoring of the test is based on the accuracy of the circle’s shape, the correct placement of the numbers, the clarity and direction of the clock hands, as well as the overall symmetry and organization of the clock. A scale from 0 to 10 or 12 is usually used, where higher scores reflect better cognitive ability.

Statistical Analysis

Regarding validity, numerous studies have demonstrated that the test accurately distinguishes individuals with cognitive disorders from healthy populations. In terms of reliability, the CDT shows high internal consistency and reproducibility in repeated administrations, making it a reliable tool for clinical practice.

References

One of the classic works in the field is the article by Shulman (1986), entitled Clock-drawing: A neuropsychological analysis, published in the journal Cognitive Neuropsychology. Also, the article by O’Connor and McFadden (2002), Clock drawing and other neuropsychological tests for detecting cognitive impairment in the elderly, provides a broad overview of the usefulness of the CDT in the geriatric population.