The clock drawing test: A systematic review and meta-analysis of diagnostic accuracy

Abstract

Aim: The aim of this study was to evaluate the accuracy of the clock drawing test and to compare its scoring methods.

Background: Dementia refers to a symptom where an adult demonstrates memory disorder and cognitive impairment. Early diagnosis of dementia is very important for medication management and prognosis. The clock drawing test is one of the most used cognitive screening tools for dementia. However, due to its scoring system, the accuracy of the clock drawing test remains a topic of debate.

Design: A systematic review with meta-analysis following Cochrane's methods and the guidelines of the Agency for Healthcare Research and Quality.

Data sources: A literature search was carried out in the OVID-MEDLINE, OVID-EMBASE and OVID-PsycINFO databases (27 October 2015).

Review method: The quality assessment of diagnostic accuracy studies (QUADAS-2) tool was employed for this review. We used hierarchical regression models to pool the values of diagnostic accuracy in a random effects model.

Results: A total of 18 studies with 5,531 participants were identified for this review. Fifteen of these studies were included for meta-analysis according to each scoring system. The pooled sensitivity and specificity of the clock drawing test using the Shulman system were 82% and 75.7% respectively. In the Sunderland system, these were 72.6% and 87.9% respectively.

Conclusions: The findings indicate that the accuracy of the clock drawing test using the Shulman system was the most studied and highly sensitive. After gaining a better understanding of the clock drawing test through this study, we recommend it for widespread use in the diagnosis of dementia.

Keywords: clock drawing test; cognitive impairment; dementia; diagnostic accuracy; literature review; meta-analysis; sensitivity; specificity; systematic review.