Quantitative and qualitative analyses of clock drawing in frontotemporal dementia and Alzheimer's disease

The clock drawing test (CDT) is a widely used cognitive screening test. It is useful in identifying focal lesions and cognitive deficits in dementia groups. Lately, several studies attempted its use to differentiate between dementia subtypes. Although many studies have examined the CDT in dementia populations, research into the use of clock drawing in frontotemporal dementia (FTD) is limited. We examined quantitative (global) and qualitative (specific error type) differences on the CDT between FTD (n = 36) and Alzheimer's disease (AD; n = 25) patients and controls without dementia (n = 25). Results showed significantly lower overall scores in the dementia groups compared to the control group, whereas FTD patients scored significantly higher than the AD group. On qualitative analysis, the FTD group had fewer stimulus bound responses, conceptual deficits, and spatial or planning errors compared to the AD group. In conclusion, both global and error analysis of the CDT helped discriminate the FTD group from controls and AD patients.