RE: Clock-Drawing Test as a Screening Tool for Cognitive Impairment Associated with Fecal Immunochemical Test Collection Errors

Clock Drawing Test: One method of knowing the informant
Originally the Clock Drawing Test (CDT) was used to assess constructional apraxia and employed in investigations of soldiers who were victims of head trauma during World War II.1 In 1986, Shulman and colleagues published the first study using the CDT as a screening tool for older adults with possible cognitive disorders.2 CDT allows for simultaneous evaluation of different cognitive abilities, including attention, comprehension, verbal working memory, numerical knowledge, visual memory and reconstruction, visuospatial skills, praxis and executive function. 3 Since 1986 there has been at least 25 CDT scoring systems develop, yet no consensus reached on which scoring method is the most accurate.1,4 When screening for dementia, CDTs are reported to be 67% to 98% sensitive and 69% to 95% specific.5
Daly et al6 used the CDT, scored with the Mendes-Santos4 and the Watson7 methods, to evaluate for cognitive impairment in a sample of 1448 participants without a history of dementia and a mean age of 63 years. Their hypothesis was that impairment demonstrated on the CDT may be associated with errors in fecal immunochemical test (FIT) sample collection. They found that being female, having 8th grade education or less, and having an abnormal clock drawing scored by Mendes-Santo’s method were associated with FIT collection errors.
Daly’s study raises an important issue for primary care physicians, as they may rely more on patients’ reports, home administered specimen collections, patient recordings of home blood pressures and data from “prediagnostic” wearables (Fitbit, other smartphone applications).8 How reliable are patients who report self -collected data and how is this data used to identify diagnoses and prescribe treatments?
A first step in calibrating the reliability of the information acquired from the patient is to evaluate the cognitive abilities of the patient. The CDT provides an easily applied quick instrument to evaluate many cognitive domains and the addition of 3-word recall covers immediate recall abilities (Mini-Cog).9 Mini-Cog screening is applied in Medicare Wellness Visits and should be considered whenever patients or families have concerns about cognitive decline. With 25 different scoring methods to choose from, how does one interpret the CDT? Since there is no consensus on which method is most accurate, I agree with Mainland10 that a qualitative assessment of “normal” versus “abnormal” may be sufficient for screening purposes, the result leading to the decision if further diagnostic testing is needed.
Thank you to the Daly team for pointing out the importance of knowing the informant or specimen collector when interpreting medical information.

1. Spenciere B, Alves H, Charchat-Fichman H. Scoring systems for the Clock Drawing Test: A historical review. Dementia & Neuropsychologia. 2017 Jan-Mar;11(1):6-14. doi:10.1590/1980-57642016dn11-010003
2. Shulman KI, Shedletsky R, Silver IL. The challenge of time clock-drawing and cognitive function in the elderly. International Journal of Geriatric Psychiatry. 1986;1(2):135-140. doi:10.1002/gps.930010209
3. Mendez MF, Ala T, Underwood KL. Development of scoring criteria for the clock drawing task in Alzheimer's disease. Journal of the American Geriatric Society. 1992 Nov;40(11):1095-1099. doi:10.1111/j.1532-5415.1992.tb01796.x
4. Mendes-Santos LC MD, Spenciere B, Charchat-Fichman H Specific algorithm method of scoring the Clock Drawing Test applied in cognitively normal elderly. Dementia & Neuropsychologia. Apr-Jun 2015 2015;9(2):128-135. doi:10.1590/1980-57642015DN92000007
5. Smedslund G, Siqveland J, Leiknes KA. Psychometric Assessment of the Clock Drawing Test [Internet]. Knowledge Centre for the Health Services at The Norwegian Institute of Public Health (NIPH), Oslo, Norway; 2015. No. 16-2015. June 2015. https://www.ncbi.nlm.nih.gov/books/NBK390574/
6. Daly JM, Xu Y, Crockett SD, Schmidt ME, Kim P, Levy BT. Clock-Drawing Test as a Screening Tool for Cognitive Impairment Associated With Fecal Immunochemical Test Collection Errors. Annals of Family Medicine. 2022 Sep-Oct;20(5):452-459. doi:10.1370/afm.2855.
7. Watson YI, Arfken CL, Birge SJ. Clock completion: an objective screening test for dementia. Journal of the American Geriatric Society. 1993;41(11)doi:10.1111/j.1532-5415.1993.tb07308.x
8. Simon DA, Shachar C, Cohen IG. Unsettled Liability Issues for "Prediagnostic" Wearables and Health-Related Products. Journal of the American Medical Association. 2022 Oct 11;328(14):1391-1392. doi:10.1001/jama.2022.16317
9. Seitz DP, CC, Newton HT, Gill SS, Herrmann N, Smailagic N, Nikolaou V, Fage BA. Mini-Cog for the diagnosis of Alzheimer's disease dementia and other dementias within a primary care setting. The Cochrane Database of Systematic Reviews. 2018 Feb 22;2(2):CD011415. doi:10.1002/14651858.CD011415.pub2
10. Mainland BJ, Amodeo S, Shulman KI. Multiple clock drawing scoring systems: simpler is better. International Journal of Geriatric Psychiatry. 2014 Feb;29(2):127-136. doi:10.1002/gps.3992
Gerald J. Jogerst, MD
Professor Emeritus
Family Medicine & Psychiatry
University of Iowa