The clock test is a simple test procedure used in the diagnosis of dementia. It is well suited to detect dementia early on. However, the clock test is not sufficient as the sole test procedure. It is therefore generally used in conjunction with another dementia diagnostics test (MMST, DemTect). Read here everything important about the clock test – how it works and is evaluated!
Dementia testing by means of clock test
Dementia (such as Alzheimer’s or vascular dementia) can be diagnosed using a variety of test procedures. One of these methods is the clock drawing test. It is easy to do and only takes a few minutes.
However, the watch test is not the only diagnostic tool for dementia. Therefore, it is always combined with another early detection test (MMST or DemTect).
The clock test is recommended for the age group 65-85.
Clock test: This is how it works
There are different variants of the clock test. In Germany, the template is usually used by Shulman (1993): The test subject is asked to enter the numbers “1” to “12” in a given circle, as they are arranged on the dial of a clock. In addition, the minute and hour hands should be drawn so that they display a specific time (usually 11:10 clock).
Sometimes the watch test variant according to Sunderland et al. (1989). The test subject must also draw the dial itself (ie the circle).
The clock test is used to test instruction comprehension, execution planning, visual memory and visuoconstructive execution. The latter is the ability to capture and reproduce a complex pattern – here a dial with a specific time.
Clock test: evaluation
When evaluating the clock test, it does not just depend on whether all digits and the two pointers are in the correct position. For example, the examiner also looks to see if the spaces between the numbers are nearly equal and the digits are clearly legible.
The more advanced a dementia, the more difficult is the clock test for those affected: The drawn clock is getting unrecognizable, the numbers and hands are incorrectly drawn or even missing. In severe dementia, many patients no longer try to draw a watch. Some people instead write words or their name on the paper.
The result of the clock test according to Shulman (1993) is rated on a scale from “1” (perfect) to “6” (no display of a clock).
The clock test evaluation in the variant according to Sunderland et al. (1989) is based on a scale from “10” (correct representation) to “1” (no longer recognizable as a clock).
Minute hand phenomenon
Sometimes the dial with its numbers and the hour hand are displayed correctly, but the minute hand is placed incorrectly. This so-called minute hand phenomenon at clock test may indicate an onset of dementia.