A comparison of five clock scoring methods using ROC (receiver operating characteristic) curve analysis

Objective To compare the accuracy of five clock scoring methods for detecti ng dementia in English-speaking patients. Design A prospective cohort study. Setting A general geriatric outpatient clinic in southwest Sydney, Australi a. Participants A total of 127 consecutive new referrals to the clinic, of mea n age 78.2 years. Measurements The clock drawing test was conducted at the beginning of each clinic appointment by a blinded observer. Each patient was then assessed by a geriatrician, who collected demographic data, administered the modified Barthel index, the geriatric depression scale, and the Folstein Mini-Mental State Examination, and categorised each patient as demented or not demente d, according to DSM-4 criteria. Each clock was scored according to the meth ods of Mendez, Shulman, Sunderland, Watson and Wolf-Klein, and evaluated fo r reliability, and predictive accuracy, using receiver operating characteri stic (ROC) curve analysis. Results The area under the ROC curve was largest for the Shulman (0.79, 95% CI 0.70-0.85) and Mendez (0.78, 95% CI 0.70-0.85) methods. Both predicted dementia more accurately than the Sunderland (area = 0.71) and Watson (area = 0.65) methods (p < 0.05). The inter-rater (0.81-0.93) and intra-rater (0 .87-0.96) correlation coefficients were high for all five methods. Conclusions While substantial differences among the clock scoring methods w ere evident in our sample, the accuracy of each was modest at best. Unless further studies in relevant settings suggest otherwise, we caution on the u se of clock drawing alone to screen for dementia. Copyright (C) 2001 John W iley & Sons, Ltd.