Regarding our January 2013 CE/CME activity (Segal-Gidan FI. Cognitive screening tools. Clinician Reviews. 2013;23(1):12-18), Lieutenant Colonel Scott A. Arcand, PA-C, LTC, SP, of the Army National Guard* asked for more information: an assessment of the described tools in terms of six core neuropsychiatric domains; and more about scoring systems for the very useful clock drawing test.
Q: At the end of the section, "Which Test to Use?", the author states that a comprehensive screening instrument would assess six core neuropsychiatric domains, but then does not assess the six instruments discussed in the article against these criteria. I would have found this a very helpful discussion. I also think it would be helpful to have a table that showed which assessments met each criterion. If a meta-analysis were done to evaluate and compare these instruments, it would lead the drive to improved tools.
In the original article, Table 2 ("Brief Cognitive Assessment Instruments") includes a column listing the cognitive functions assessed by each of the six screening tools reviewed/discussed. Each of these components corresponds to one or more neuropsychological domain, and I refer the reader to the referenced paper for a more detailed discussion of this (Cullen et al,1 2007). Two screening tests, the Modified Mini–Mental State Exam (3MS) and the Mini–Mental State Exam (MMSE) include—at least in part—each of the suggested six core neuropsychological domains. These two tests would be considered the most complete according to the standard of the six core neuropsychological domains; however, they also take the most time to administer (10 to 15 minutes), as noted in the original article's Table 2.
The Clinician's Choice
For clinicians deciding which test is most appropriate to use as a screening tool in their practice or for an individual patient, they should weigh several factors, including the length and time to administer, as well as the domains assessed. Table 1, I hope, will more directly address the reader's issue of which neuropsychological domain is assessed in the test items for each of the cognitive screening tests reviewed in the article.
Q: Regarding the clock drawing test (CDT), the author makes two statements: that there are multiple scoring systems for the CDT, and that the CDT has been shown to be highly predictive of driver safety. I would be interested to see at least one of these scoring systems. Additionally, how low a score on the CDT would it take to indicate that a patient is (or could be) unfit for driving?
Scoring systems for the CDT, varying from four- to 20-point scales, evaluate accuracy of components and traits of the drawing, or they categorize errors. In a 2001 overview of various CDT scoring systems, Peter Braunberger2 included a detailed review of two scoring strategies:
A simple scoring system created by Shua et al,3 in which one point is awarded for each of the following:
• Approximate drawing of the clock
• Presence of numbers in the correct sequence
• Correct spatial arrangement of numbers
• Presence of clock hands
• Hands showing the approximate correct time
• Hands depicting the exact time
In the second scoring system, proposed by Shulman et al,4 six different scores are possible (see Table 24).
Driver Safety
Regarding use of the CDT as a predictor of driver safety, Freund and colleagues5 conducted a study of clock drawing and simulator driving assessment. In addition to finding four CDT scoring scales comparable, they discovered that as patients' CDT scores decreased, the number of "driving errors" they made increased. As shown in Table 3,5 the researchers' CDT scoring system focused on time, numbers, and spacing, with a maximum score of seven points.
References
1. Cullen B, O'Neill B, Evans JJ, et al. A review of screening tests for cognitive impairment. J Neurol Neurosurg Psychiatry. 2007;78(8):790-799.
2. Braunberger P. The clock drawing test (2001) www.neurosurvival.ca/ClinicalAssistant/scales/clock_drawing_test.htm. Accessed March 23, 2013.
3. Shua-Haim J, Koppuzha G, Gross J. A simple scoring system for clock drawing in patients with Alzheimer's disease. J Am Geriatr Soc. 1996;44:335.
4. Shulman KI, Gold DP, Cohen CA, Zucchero CA. Clock-drawing and dementia in the community: a longitudinal study. Int J Geriatr Psychiatry. 1993;8:487-496.
5. Freund B, Gravenstein S, Ferris R, et al. Drawing clocks and driving cars. J Gen Intern Med. 2005;20:240-244.
*Scott A. Arcandis currently serving on active duty as a member of the Army National Guard. The statements expressed here are those of the writer and do not constitute official policy of the Department of Defense, the Department of the Army, or the National Guard Bureau.