The Clock Drawing Test: Performance Among Elderly with Low Educational Level

Objective: To compare the accuracy of four scales, and to determine the inter-rater reliability and the influence of schooling on Clock Drawing Test performance in screening for dementia in elderly with low educational level.

Method:

Design: Criterion validation, concurrent type.

Setting: Outpatient unit of Universidade do Estado do Rio de Janeiro Hospital, Brazil.

Participants: A total of 306 individuals (> or = 65 years) were assessed by a geriatrician and a neuropsychologist using functional and cognitive instruments. The diagnosis of dementia was established by consensus in a meeting between these professionals. Four different researchers blinded as to the cognitive status of the patients scored the Clock Drawing Test using Shulman's, Sunderland's, Manos', and Wolf-Klein's methods; and a fifth researcher assessed Manos' method for an inter-rater reliability study.

Results: The data of 211 individuals (< or = 4 years of schooling) were analyzed. The sensitivity and specificity of the four methods were similar (about 65%). The inter-rater reliability of Manos' method was excellent (ICC = 0.944). The areas under the ROC curves were small (0.657 to 0.681), and the differences between them were not statistically significant.

Conclusions: The Clock Drawing Test is a reliable but not valid test to screen for dementia in older outpatients with 4 or less years of formal schooling.