Drawing a clock by hand is one of easiest to administer and one of the most popular screening tools that can help to detect mild cognitive impairment, dementia, or Alzheimer's among new patients. The test can be done anytime, anywhere, and can be self-administered as well.
There are numerous versions of the clock-drawing test. They all involve asking the patient to draw the face of a clock. Variations include providing a blank piece of paper or a paper with a pre-drawn (often 10 cm diameter) circle and asking the patient to draw the face of a clock. Further questions from the patients may be politely deferred by repeating the request to draw the face of a clock. Most variations of the test also include asking the patient to draw in the arms to denote certain time. Many times have been used including, 3:00, 3:40, 8:40, 2:45 and so on. They time 11:10 has been suggested as useful because of the distraction of "pull" of the numeral ten on the clock when setting a time. Generally there is no time limit to the test, but the test usually takes only one to two minutes.
If you administer the test to somebody else, in general, look first at symmetry of the numbers of the clock. This can indicate whether or not the patient was able to plan ahead. Leaving numbers out, repeating numbers, or continuing past the number 12 is also an indication of abnormality. Secondly, look at the hands. Deliberately choose a time from the offered list that is not straightforward because you are looking for disinhibition or “frontal pull.” The time ‘ten after eleven’ requires that the patient inhibit a reflex to put the hands at the numbers 10 and 11. This also requires abstract thinking to translate the concept of time into a drawing.
Test Description
- Draw a clock by hand on a large piece of paper (about 10 cm in diameter).
- Draw the face of a clock and put the numbers in the correct positions.
- Then draw the hands to indicate 3:40 (time).
Standard Scoring
To score, assign the following points for each part of the drawing:
- 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.
Less points you get in the test, more you should worry about the potential symptoms of Alzheimer’s Disease. A normal score is four or five points out of five.
A simple similar results interpretation is offered by Stahelin:
· The number 12 must appear on top (3 points),
· There must be 12 numbers present (1 point),
· There must be two distinguishable hands (1 point),
· The time must be identified correctly (1 point) for full credit.
A score less than 4 (out of 6) is considered impaired.
Advanced Scoring
While the test itself is very easy and fast to administer or self-administer, and standard scoring process is equally easy and fast to obtain results, there are a number of variations on advanced scoring the clock, more than variations in administering the test itself. Most scoring systems are highly correlated with well-established measures including the MMSE, Dementia Rating Scale and the Global Deterioration Scale. Let’s briefly review the main advanced scoring approaches:
- Mendez et al. 1992. Clock Drawing Interpretation Scale (CDIS) with the time "ten minutes past eleven." Each positive result earns a score 1.
1. There is an attempt to indicate a time in any way.
2. All marks or items can be classified as either part of a closure figure, a hand or a symbol for clock numbers.
3. There is a totally closed figure without gaps ("the closure figure"). Score only if symbols for clock numbers are present.
4. A "2" is present and pointed out in some way for the time.
5. Most symbols are distributed as a circle without major gaps.
6. Three or more clock quadrants have one or more appropriate numbers per respective quadrant.
7. Most symbols are ordered in a clockwise fashion.
8. All symbols are totally within a closure figure.
9. An "11" is present and is pointed out in some way for time.
10. All numbers 1 to 12 are present.
11. There are no repeated or duplicated number symbols.
12. There are no substitutions for Arabic or Roman numerals.
13. The numbers do not go beyond the number 12.
14. All symbols lie about equally adjacent to a closure figure edge.
15. Seven or more of the same symbol type are ordered sequentially. Score only if one or more hands are present.
16. All hands radiate from the direction of a closure figure's center.
17. One hand is visibly longer than another hand.
18. There are two distinct and separable hands.
19. All hands are totally within a closure figure.
20. There is an attempt to indicate a time with one or more hands.
- Lam et al. 1998. Scoring criteria for clock drawing test. Chose score by description of the produced clock. Lower score you get – smaller signs of Alzheimer’s.
- 0 - Correct time shown with normal spacing.
- 1 - Slight impairment in spacing of lines or numbers.
- 2 - Noticeable impairment in line spacing.
- 3 - Incorrect spacing between numbers with subsequent inappropriate denotation of time.
- 4 - Obvious errors in time denotation (arms misplaced, numbers in wrong place)
- 5 - Abnormal clock-face drawing with inaccurate time denotation (e.g. reversal of numbers, perseveration beyond twelve, misplaced numbers, drawing only to one side, omitting most numbers)
- 6 - Abnormal clock face drawing with inaccurate time denotation (e.g. reversal of numbers, perseveration beyond twelve, misplaced numbers and drawing to one side and omitting most numbers).
- 7 - A recognizable attempt to draw a clock face but no clear denotation of time.
- 8 - Some evidence that a clock face is drawn.
- 9 - Minimal evidence that a clock face is drawn.
- 10 - No reasonable attempt to drawing a clock face (exclude gross visual disturbance, hemiplegia and severe psychotics state).
- Wolf-Klein et al. 1989. Scoring criteria for clock drawing test. Chose score by description of the produced clock. Higher score you get – smaller signs of Alzheimer’s.
· X - Normal
· IX - almost normal except for number
· VIII - almost normal except for spacing
· VII - very inappropriate spacing
· VI - perseveration
· V - absence of numbers
· IV - counter clockwise rotation
· III - other
· II - irrelevant spatial arrangement
· I - irrelevant figures
- Shua-Haim et al. 1996. Simple scoring system. Award one point for each of the following:
- Approximate drawing of the clock face.
- Presence of numbers in sequence.
- Correct spacial arrangement of numbers
- Presence of clock hands
- Hands showing approximately the correct time
- Hands depicting the exact time
- Shulman et al. 1986. Classification of clock errors with the time
1. Visual spatial
a. Mildly impaired spacing of times
b. Draws lines outside of circle
c. Turns page while writing numbers so that some numbers appear upside down
d. Draws in lines to orient spacing.
2. Error in denoting time as 3 o'clock
a. Omits minute hand
b. Draws single line from 3 to 12
c. Writes words 3 o'clock
d. Writes number three again
e. Circles or underlines 3
f. Unable to indicate 3 o'clock
3. Visual spatial
a. Moderately impaired spacing of lines
b. Omits number
c. Perseveration
i. Repeats circle
ii. Continues on past 12 to 13, 14, 15 etc
iii. Counter-clockwise
iv. Dysgraphia
4. 4. Severely disorganized spacing
a. Confused time, writes in minutes, times of day, months or seasons
b. Draws picture of human face
c. Writes words "clock"
5. Unable to make reasonable attempt at clock
a. Exclude severe depression or psychotic state.
- Sunderland et al. 1983. This is one of the most popular scoring systems for evaluating clock drawings. Higher the score – better the patient mental state. This method usually involves giving patients a pre-drawn circle.
· 10-6 - Drawing of clock face with number and circle generally intact
o 10 - Hands in correct position (i.e. Hours hand approaching 3 o'clock)
o 9 - Slight errors in placement of hands.
o 8 - More noticeable errors in placement of hour and minute hands
o 7 - Placement of hands is significantly off course
o 6 - Inappropriate use of clock hands (i.e. use of digital display or circling numbers despite repeated instructions).
· 5-1 -Drawing of clock face with circle and numbers is NOT intact
o 5 - Crowding of numbers at one end of the clock or reversal of numbers. Hands may still be present in some fashion.
o 4 - Further distortion of number sequence. Integrity of clock face is now gone (i.e. numbers missing or placed outside of boundaries of the clock face)
o 3 - Numbers and clock face no longer obviously connected in the clock drawing. Hands are not present.
o 2 - Drawing reveals some evidence of instructions being received but only vague representation of a clock.
o 1 - Either no attempt or an uninterpretable effort is made.
- SHULMAN scoring system, 1993. Scoring criteria is presented below, while lower score gives higher warnings.
- 0 - No reasonable representation of a clock
—No attempts at all
—No semblance of a clock at all
—Writes a word or name
- 1- Severe level of disorganization as described in 2
- 2 - Moderate visio-spatial disorganization of times such that accurate denotation of 10 after 11 is impossible
—Moderately poor spacing
—Omits numbers
—Perseveration—repeats circle or continues on past 12 to 13, 14, 15 etc.
—Right-left reversal—numbers drawn counterclockwise
—Dysgraphia—unable to write numbers accurately
- 3- Inaccurate representation of 10 after 11 when visio-spatial organization is perfect or shows only minor deviations
—Minute hand points to 10
—Writes ‘10 after 11’
—Unable to make any denotation of time
- 4 - Minor visio-spatial errors
—A mildly impaired spacing of times
—Draws times outside circle
—Turns page while writing numbers so that some numbers appear upside down
—Draws in lines (spokes) to orient spacing
- 5 - Perfect clock
- Watson Scoring System. The Watson method of scoring the CDT divides the clock into four quadrants. This technique does not score the hands, but focuses exclusively on the placement of numbers or symbols within each quadrant.
Scoring is performed through the following approach:
- Draw one line through the center of the circle and the number 12 or mark that best corresponds to the number 12. Draw another line perpendicular to this line also through the middle of the circle. This will divide the clock into four segments.
- Moving in a clockwise fashion, count the number of digits in each quadrant beginning with the number 12. If a digit falls on one of the quadrant lines, it is included in the quadrant preceding the line. A total of 3 digits in one quadrant is considered correct.
- If there is an error in numbers of digits in the first three quadrants (spanning numbers 12 through 9), assign a score of 1. For any error in the number of digits in the last quadrant, assign a score of 4.
- The sum of the scores for each quadrant is the total score for the clock.
- Normal range of scores is 0 to 3. Abnormal range of scores is 4 to 7.
If you administer the test on your own and find the results either disconcerting or suspicious, schedule an appointment with your personal care physician. Take the copy of the clock test with you to the doctor appointment, and show the test to the doctor. Insist on a referral to a memory specialist for testing.
There are many diseases that can present as dementia or Alzheimer's. Getting the correct diagnosis is difficult under any and all circumstances. You need to be sure all the proper tests are administered.
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