The Clock-Drawing Test
by Dr.Peter Braunberger (2001)

 

Setting and scoring the test
         Three easy steps
          Scoring
Why do test?
Sensitive and specific
Example clock
References
Appendix of Scoring Methods
         Mendez et al. 1992
         Lam et al 1998
         Wolf-Klein et al. 1989
         Shua-Haim et al. 1996
         Shulman et al. 1986
         Sunderland et al. 1983

 

Setting and Scoring the Test

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, 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.

          3 Easy Steps

  1. Provide patient with a piece of paper with a pre-drawn circle of approximately 10 cm in diameter.
  2. Indicate that the circle represents the face of a clock and ask the patient to put in the numbers so that it looks like a clock.
  3. Ask the patient to add arms so that the clock indicates the time "ten minutes after eleven."

          Scoring

There are a number of variations on 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.

Perhaps the quickest scoring technique involves dividing the clock into four quadrants and counting the numbers in the correct quadrant. More complex assessments include evaluating 20 traits, or categorizing errors conceptually.

Common methods of scoring are as follows:
          Sulman et al 1986
          Sunderland et al 1989
          Wolf-Klein et al 1989
          Mendez et al 1992
          Shua-Haim et al 1996
          Lam et al 1998

Why do the Test?

The clock has been proposed as a quick screening test for cognitive dysfunction secondary to dementia, delirium, or a range of neurological and psychiatric illnesses. Many health care workers are faced with questions regarding the function and safety of patients in differing environments. A quick screening for cognitive function may contribute an overall assessment of required investigations and resources for the patient.

The clock drawing test may complement other quick screening tests including the MMSE and is a component of the "7 Minute Neurocognitive Screening Battery" (Solomon et al 1998).

The strength and weakness of the clock-drawing test lies in the number of cognitive, motor and perceptual functions required simultaneously for successful completion. orientation, conceptualization of time, visual spatial organization (Lam et al 1998) memory and executive function (Estaban-Santillan et al 1998), auditory comprehension, visual memory, motor programming, numerical knowledge, semantic instruction, inhibition of distracting stimuli, concentration and frustration tolerance (Shulman 2000) have all been highlighted as contributing to the successful clock. Royall (1996) suggests the executive function required for clock-drawing involves "control functions which guide complex goal-directed behaviour in the face of novel and irrelevant or ambiguous environmental cues", and that similar demands are shared by independent living skills.

The completely normal clock is therefore a suggestion that a number of functions are intact and contributes to the weight of evidence that the patient may, for example, be able to continue independently. Alternatively, a grossly abnormal clock, is an important indicator of potential problems warranting further investigation or resource allocation.

While the grossly abnormal clock demands immediate attention, questions regarding the importance of minor errors remain. Shulman (2000) suggests that serial clock drawing can be used to follow a progressive dementing process, or recovery from a toxic delirium. Esteban-Santillan et al (1998) suggest that minor clock errors are suggestive of a dementing process. They also highlight the placement of the arms as the most abstract feature of clock drawing, and therefore useful in early dementing processes.

Clock errors may be divided into categories including visuo-spatial, perseveration, grossly disorganized. Common errors in Alzheimer's disease include perseveration, counter-clockwise numbering, absence of numbers and irrelevant spatial arrangement. Errors following stroke may reflect spatial neglect, hemianopsia and sensory loss, in addition to errors suggestive of cognitive dysfunction (Freidman 1991). Lam et al (1998) were unable to differentiate Alzheimer's Disease and Multi-infarct dementia according to clock errors.

A variety of psychiatric conditions contribute potentially to abnormal clock-drawing, (Gruber et al 1997). Lee & Lawlor report on a subset of patients whose clock drawings improved significantly when treated for depression. Cognitive decline and psychotic state both contributed to poor scores in a clock-drawing test of elderly patients with a long-standing diagnosis of schizophrenia (Heinik et al 1997).

Sensitivity and specificity, likelihood ratio and positive predictive value have all been used to measure the potential value of the clock-drawing test as a screening tool (Shulman 2000). These vary with the score on the clock drawing test. Sensitivity (i.e. few false negatives) to dementia across many studies range from 75 to 92 percent depending on the population being assessed, and averaged 85%. Specificity (ie. few false positives) 65 to 96 percent with an average of 85%, however clock errors may predict many conditions in addition to dementia and it is important to maintain a wide differential diagnosis with clock errors.

 

References

Borson, S. et al. 1999. The clock drawing test: utility for dementia detection in multiethnic elders. Journal of Gerontology Medical Sciences 54A:M534-M540.

Esteban-Santillan, C. et al. 1998. Clock drawing test in very mild Alzheimer's Disease. Journal of the American Geriatrics Society 46:1266-1269.

Friedman, PJ. 1991. Clock drawing in acute stroke. Age and Ageing. 20:140-145.

Gruber et al. 1996. A comparison of the clock drawing test and the Pfeiffer Short Portable Mental Status Questionnaire in a geopsychiatry clinic. International Journal of Geriatric Psychiatry. 12:526-532.

Heinik, J. et al. 1997. Clock drawing test in elderly schizophrenia patients. International Journal of Geriatric Psychiatry. 12:653-655.

Heinik, J. et al. 2000. Comparison of a clock drawing test in elderly schizophrenic and Alzheimer disease patients: A preliminary study. International journal of geriatric Psychiatry. 15:638-643.

Lam, LCW. et al. 1998. Clock-face drawing, reading and setting test in the screening of dementia in Chinese elderly adults. Journal of Gerontology. 53B:353-357.

Lee, L., and Lawlor, BA. 1995. State dependent nature of the clock-drawing task in geriatric depression. Journal of the American Geriatric Society. 43:796-798.

Mendez et al. 1992. Development of scoring criteria for the clock drawing task in Alzheimer's Disease. Journal of the American Geriatric Society. 40:1095-1099.

Royall, DR. 1996. Comments of the executive control of clock-drawing. Journal of the American Geriatric Society. 44:218-219.

Shua-Haim et al. 1996. A simple scoring system for clock-drawing in patients with Alzheimer's disease. Journal of the American Geriatric Society. 44:335.

Shulman, K.I. 2000. Clock-drawing: Is it the ideal cognitive screening test? International Journal of Geriatric Psychiatry. 15:548-561.

Solomon et al. 1998. A seven minute neurocognitive screening battery highly sensitive to Alzheimer's disease. Archives of Neurology. 55:349-355.

Sunderland, T. et al. 1989. Clock drawing in Alzheimer's Disease: A novel measure of dementia severity. Journal of the American Geriatric Society. 37:725-729.

Wolf-Klein, G.P. et al. 1989. Screening for Alzheimer's Disease by clock drawing. Journal of the American Geriatric Society. 37:730-734.

 

Appendix: Scoring Methods

Mendez et al. 1992. Clock Drawing Interpretation Scale (CDIS) with the time "ten minutes past eleven."

  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.

Score Description of clock
0 Correct time 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 (eg. 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 (eg 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.

Clock Type Description
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
    1. Mildly impaired spacing of times
    2. Draws lines outside of circle
    3. Turns page while writing numbers so that some numbers appear upside down
    4. Draws in lines to orient spacing.
  2. Error in denoting time as 3 o'clock
    1. Omits minute hand
    2. Draws single line from 3 to 12
    3. Writes words 3 o'clock
    4. Writes number three again
    5. Circles or underlines 3
    6. Unable to indicate 3 o'clock
  3. Visual spatial
    1. Moderately impaired spacing of lines
    2. Omits number
    3. Perseveration
      1. Repeats circle
      2. Continues on past 12 to 13, 14, 15 etc
      3. Counter-clockwise
      4. Dysgraphia
  4. 4. Severely disorganized spacing
    1. Confused time, writes in minutes, times of day, months or seasons
    2. Draws picture of human face
    3. Writes words "clock"
  5. Unable to make reasonable attempt at clock
    1. Exclude severe depression or psychotic state)

 

Sunderland et al. 1983. A PRIORI criteria for evaluating clock drawings.

10-6 Drawing of clock face with number and circle generally intact
10 Hands in correct position (ie. Hours hand approaching 3 o'clock)
9 Slight errors in placement of hands.
8  More noticeable errors in placement of hour and minute hands
7 Placement of hands is significantly off course
6 Inappropriate use of clock hands (ie. use of digital display or circling numbers despite repeated instructions)
5-1 Drawing of clock face with circle and numbers is NOT intact
5 Crowding of numbers at one end of the clock or reversal of numbers. Hands may still be present in some fashion.
4 Further distortion of number sequence. Integrity of clock face is now gone (ie. numbers missing or placed outside of boundaries of the clock face)
3 Numbers and clock face no longer obviously connected in the clock drawing. Hands are not present.
2 Drawing reveals some evidence of instructions being received but only vague representation of a clock.
1 Either no attempt or an uninterpretable effort is made.

 

 

Sensitivity and Specificity

Sensitivity = (true positive)/(true positive + false negative)

Specificity = (true negative)/(true negative + false positive)