Qualitative analyses of clock drawings in Alzheimer's disease and vascular dementia

Although quantitative analyses of clock drawings (CD) have achieved widespread clinical use as a cognitive screening, little is known about the qualitative profiles of CD in Alzheimer's disease (AD) and vascular dementia (VD). To address this issue, the present study examined the significance of qualitative analyses of CD in AD and VD. Sixty-seven AD patients, 44 VD patients and eight controls underwent a clock drawing test and took the Mini-Mental State Examinations (MMSE). In the dementia groups, quantitative scores significantly decreased compared with controls and were significantly correlated with MMSE scores. Qualitative analysis demonstrated that in AD patients qualitative error patterns were stable and independent of severity. In contrast, in VD patients the frequency of graphic difficulties and conceptual deficit increased, while the frequency of spatial and/or planning deficit decreased, as severity worsened. In mild dementia groups the frequency of spatial and/or planning deficit was significantly higher in VD. In moderate dementia groups, the frequency of graphic difficulties was significantly higher in VD and the difference in the frequency of spatial and/or planning deficit seen in mild dementia disappeared. The present study suggests that qualitative analyses of clock drawings could demonstrate the neuropsychological profiles of AD and VD and their differences between these dementias.