Clock Drawing Test (CDT)

Overview

 Until recently, data on the psychometric properties of the CDT were limited. While there are many possible ways to administer and score the CDT, the psychometric properties of all the various systems seem consistent and all forms correlate strongly with other cognitive measures (Scanlan et al., 2002; Ruchinskas & Curyto, 2003; McDowell & Newell, 1996). Further, scoring of the CDT has been found to be both accurate and consistent in patients with stroke (South et al., 2001).
For the purposes of this review, we conducted a literature search to identify all relevant publications on the psychometric properties of the more commonly applied scoring methods of the CDT. We then selected to review articles from high impact journals, and from a variety of authors.

Reliability

Test-retest reliability

(using Spearman rank order correlations) of the CDT has been reported by several investigators using a variety of scoring systems:

  • Manos and Wu (1994) reported an “excellent” 2-day test-retest reliability of 0.87 for medical patients and 0.94 for surgical patients.
  • Tuokko et al. (1992) reported an “adequate” test-retest reliability of 0.70 at 4 days.
  • Mendez et al. (1992) reported and “excellent” coefficients of 0.78 and 0.76 at 3 and 6 months, respectively.
  • Freedman et al. (1994) reported test-retest reliability as “very low”. However, when the “10 after 11” time setting was used with the examiner clock, which is known to be a more sensitive setting for detecting cognitive dysfunction, test-retest reliability was found to be “excellent” (0.94).

Inter-rater reliability of the CDT, as indicated by Spearman rank order correlations (not the preferred method of analyses for assessing inter-rater reliability but one used in earlier measurement research), has also been reported by several investigators:

  • Sunderland et al. (1989) found “excellent” coefficients ranging from 0.86 to 0.97 and found no difference between clinician and non-clinician raters (0.84 and 0.86, respectively).
  • Rouleau et al. (1992) found “excellent” inter-rater reliability, with coefficients ranging from 0.92 to 0.97.
  • Mendez et al. (1992) reported “excellent” inter-rater reliability of 0.94.
  • Tuokko et al. (1992) reported high coefficients ranging from 0.94 to 0.97 across three annual assessments.
  • The modified Shulman scale (Shulman, Gold, Cohen, & Zucchero, 1993) also has “excellent” inter-rater reliability (0.94 at baseline, 0.97 at 6 months, and 0.97 at 12 months).
  • Manos and Wu (1994) obtained “excellent” inter-rater reliability coefficients ranging from 0.88 to 0.96.
  • Freedman et al. (1994) reported coefficients ranging from 0.79 to 0.99 on the free-drawn clocks, 0.84 to 0.85 using the pre-drawn contours, and 0.63 to 0.74 for the examiner clocks, demonstrating “excellent” inter-rater reliability.

South et al. (2001) compared the psychometrics of 3 different scoring methods of the CDT (Libon revised system; Rouleau rating scale; and Freedman scoring system) in a sample of 20 patients with stroke. Intra-rater reliability were measured using the intraclass correlation coefficient (ICC). Raters used comparable criteria for each score demonstrating “excellent” inter-rater reliability. Raters used similar scoring criteria throughout, demonstrating “excellent” intra-rater reliability. South et al. (2001) concluded that while the Libon scoring system demonstrated a range of reliabilities across different domains, the Rouleau and Freedman systems were in the excellent range.

Validity

In a review, Shulman (2000) reported that most studies achieved sensitivities and specificities of approximately 85% and concluded that the CDT, in conjunction with other widely used tests such as the Mini-Mental State Examination (MMSE), could provide a significant advance in the early detection of dementia. In contrast, Powlishta et al. (2002) concluded from their study that the CDT did not appear to be a useful screening tool for detecting very mild dementia. Other authors have concluded that the CDT should not be used alone as a dementia screening test because of its overall inadequate performance (Borson & Brush, 2002; Storey et al., 2001). However, most of the previous studies were based on relatively small sample sizes or were undertaken in a clinical setting, and their results may not be applicable to a larger community population.

Nishiwaki et al. (2004) studied the validity of the CDT in comparison to the MMSE in a large general elderly population (aged 75 years or older). The specificity of the CDT for detecting moderate-to-severe cognitive impairment (MMSE score = 17) were 77% and 87%, respectively, for nurse administration and 40% and 91%, respectively, for postal administration. The authors conclude that the CDT may have value as a brief face-to-face screening tool for moderate/severe cognitive impairment in an older community population but is relatively poor at detecting milder cognitive impairment.

Few studies have examined the validity of the CDT specifically in patients with stroke. Adunsky et al. (2002) compared the CDT with the Mini-Mental State Examination (MMSE) and cognitive Functional Independence Measure (FIM) (cognitive tests used for the evaluation of functional outcomes at discharge in elderly patients with stroke). The tests were administered to 151 patients admitted for inpatient rehabilitation following an acute stroke. Correlation coefficients (Pearson correlation) between the three cognitive tests resulted in r-values ranging from 0.51 to 0.59. Adunsky et al. (2002) concluded that they share a reasonable degree of resemblance to each other, accounting for “adequate” concurrent validity of these tests.

Bailey, Riddoch, and Crome (2000) evaluated a test battery for hemineglect in elderly patients with stroke and determined that the CDT had questionable validity in the assessment of representational neglect. Further, consistent with previous findings (Ishiai et al., 1993; Kaplan et al., 1991), the utility of the CDT as a screening measure for neglect was not supported from these results. Reasons include the subjectivity in scoring, and questionable validity in that the task may also reflect cognitive impairment (Freidman, 1991), constructional apraxia, or impaired planning ability (Kinsella, Packer, Ng, Olver, & Stark, 1995).

Responsiveness

Not applicable.

References
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  • Bailey, M. J., Riddoch, J., Crome, P. (2002). Evaluation ofa test battery for hemineglect in elderly stroke patients for use by therapists in clinical practice. Neurorehabilitation, 14(3), 139-150.

  • Borson, S., Brush, M., Gil, E., Scanlan, J., Vitaliano, P.,Chen, J., Cahsman, J., Sta Maria, M. M., Barnhart, R., Roques, J. (1999). The Clock Drawing Test: Utility for dementia detection in multiethnic elders. J Gerontol A Biol Sci Med Sci, 54, M534-40.

  • Dastoor, D. P., Schwartz, G., Kurzman, D. (1991).Clock-drawing: An assessment technique in dementia. Journal of Clinical and Experimental Gerontology, 13, 69-85.

  • Freedman, M., Leach, L., Kaplan, E., Winocur, G., Shulman,K. I., Delis, D. C. (1994). Clock Drawing: A Neuropsychological Analysis (pp. 5). New York: Oxford University Press.

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  • Heinik, J., Solomesh, I., Berkman, P. (2004). Correlationbetween the CAMCOG, the MMSE and three clock drawing tests in a specialized outpatient psychogeriatric service. Arch Gerontol Geriatr, 38, 77-84.

  • Heinik, J., Solomesh, I., Lin, R., Raikher, B., Goldray, D.,Merdler, C., Kemelman, P. (2004). Clock drawing test-modified and integrated approach (CDT-MIA): Description and preliminary examination of its validity and reliability in dementia patients referred to a specialized psychogeriatric setting. J Geriatr Psychiatry Neurol, 17, 73-80.

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  • Lee, H., Lawlor, B. A. (1995). State-dependent nature of theClock Drawing Task in geriatric depression. Journal of the American Geriatrics Society, 43, 796-798.

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  • Manos, P. J., Wu, R. (1994). The Ten Point Clock Test: Aquick screen and grading system for cognitive impairment in medical and surgical patients. International Journal of Psychiatry in Medicine, 24, 229-244.

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  • Nishiwaki, Y., Breeze, E., Smeeth, L., Bulpitt, C. J.,Peters, R., Fletcher, A. E. (2004). Validity of the Clock-Drawing Test as a Screening Tool for Cognitive Impairment in the Elderly. American Journal of Epidemiology, 160(8), 797-807.

  • Paganini-Hill, A., Clark, L. J., Henderson, V. W., Birge, S.J. (2001). Clock drawing: Analysis in a retirement community. J Am Geriatr Soc, 49, 941-947.

  • Powlishta, K. K., von Dras, D. D., Stanford, A., Carr D. B.,Tsering, C., Miller, J. P., Morris, J. C. (2002). The Clock Drawing Test is a poor screen for very mild dementia. Neurology, 59, 898-903.

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  • Scanlan, J. M., Brush, M., Quijano, C., Borson, S. (2002).Comparing clock tests for dementia screening: naïve judgments vs formal systems – what is optimal? International Journal of Geriatric Psychiatry, 17(1), 14-21.

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  • South, M. B., Greve, K. W., Bianchini, K. J., Adams, D.(2001). Inter-rater reliability of Three Clock Drawing Test scoring systems. Applied Neuropsychology, 8(3), 174-179.

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  • Storey, J. E., Rowland, J. T., Basic, D., Conforti, D. A.(2001). A comparison of five clock scoring methods using ROC (receiver operating characteristic) curve analysis. Int J Geriatr Psychiatr, 16, 394-9.

  • Sunderland, T., Hill, J. L., Mellow, A. M., Lowlor, B. A.,Grundersheimer, J., Newhouse, P. A., Grafman, J. H. (1989). Clock drawing in Alzheimer’s disease: a novel measure of dementia severity. J Am Geriatr Soc, 37(8), 725-729.

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  • Tuokko, H., Hadjistavropoulos, T., Miller, J. A., Beattie,B. L. (1992). The Clock Test, a sensitive measure to differentiate normal elderly from those with Alzheimer disease. Journal of the American Geriatrics Society, 40, 579-584.

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