Differential scoring patterns on the clock drawing test: A comparison of vascular dementia and Alzheimer's dementia

This study examined differences in scoring patterns among those diagnosed with Alzheimer's dementia and vascular dementia on the clock-drawing test. Archival clock drawing data was retrieved on 279 patients presenting at a county hospital-based memory clinic. Analysis of drawings was based on frequency of qualitative errors, as well as an overall quantitative score. Mean comparisons found those patients with Alzheimer's dementia to perform worse on both quantitative and qualitative scoring measures. However, Pearson's chi-squared test revealed a significantly higher rate of spacing errors among subjects with vascular dementia. Such lends support to my hypothesis that impaired executive functioning in vascular dementia patients would lead to poor qualitative performance. Logistic regression found significant predictive ability for the qualitative criteria in diagnosis (chi2 = 25.49, p < .001), particularly the rate of omission ( z = 8.96, p = .003) and addition errors ( z = 7.58, p = .006). Such findings hold important implications for the use of qualitative criteria in cognitive screening assessments.