Characteristics of clock drawing test (CDT) errors by the dementia type: quantitative and qualitative analyses.

We wanted to define the characteristics of errors on the clock drawing test (CDT) and we also wanted to determine their value for making the early diagnosis of dementia, so the performance of patients with three types of dementia on the four CDT was evaluated. The patients with subcortical vascular dementia (VaD) and patients with Parkinson's disease with dementia (PDD) had more stimulus bound responses. Patients with Alzheimer disease (AD) made significantly more conceptual deficit (CD) errors. The CD correlated with the severity of dementia and it could be detected in the early and mild stage of dementia. Qualitative and quantitative analyses of the errors on the CDT might be useful for making the early differential diagnosis of dementia types.