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Clock Drawing Test


Updated: April 19, 2006

Dementia Clock Test
image: hypatia
Improved Version Available An updated version of this article is available. Please view The Clock-Drawing Test.

This is a simple test that can be used as a part of a neurological test or as a screening tool for Alzheimer's and other types of dementia.

The person undergoing testing is asked to;
Draw a clock
Put in all the numbers
Set the hands at ten past eleven.

Scoring system for Clock Drawing test (CDT)
There are a number of scoring systems for this test. The Alzheimer's disease cooperative scoring system is based on a score of five points.
1 point for the clock circle
1 point for all the numbers being in the correct order
1 point for the numbers being in the proper special order
1 point for the two hands of the clock
1 point for the correct time.

A normal score is four or five points.

Test results
The test can provide huge amounts of information about general cognitive and adaptive functioning such as memory, how people are able to process information and vision. A normal clock drawing almost always predicts that a person's cognitive abilities are within normal limits.

The clock Drawing test does offer specific clues about the area of change or damage.

Research varies on the ability of the Clock Drawing test to differentiate between, for example, vascular dementia and Alzheimer's disease.

The CDT has been shown to lack sensitivity for mild cognitive impairment.

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