The clock-drawing test (CDT) is a simple tool used to check for signs ofdementia, includingAlzheimers disease.
It is often used in combination with otherscreening testsbut can provide valuable clues on its own.
To complete the clock-drawing test, one must draw a clock with hands pointing to a specific time.
Verywell / Jessica Olah
It also discusses some of the benefits and drawbacks of testing.
This ability is often lost in people with early dementia.
Any difficulties with the task suggest that a person may have dementia.
It only requires a pencil and a piece of paper with a pre-drawn circle on it.
The doctor will first ask the person to draw the numbers on the face of the clock.
Next, the person will be asked to draw the hands to show a specific time.
Different times can be used, but many doctors choose 10 minutes after 11 as a standard value.
The word “hands” is not used to avoid giving clues.
A total of three drawings are typically used with each drawing done within a specific time limit.
Clock-Drawing Test Scoring
There are as many as 15 different ways to score the clock-drawing test.
Even the refusal to draw a clock may be interpreted as a sign of dementia.
This simplest scoring method allots one point if the drawing is correct and zero points if it is not.
For its part, the Alzheimer’s Association endorses the simple method of scoring.
The inability to do so is a strong indication of mental decline.
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