We sought to identify the relationship between regional cerebral blood flow (rCBF) and error types on the Clock Drawing Test (CDT) in patients with Alzheimer's disease (AD).Method:
The CDT was administered to 142 patients with AD. We used the Mendez scoring method. Their rCBF values were measured by single-photon emission computed tomography. The correlation between the CDT total score and rCBF was examined on a voxel-by-voxel basis. After we excluded 37 patients whose drawings were inappropriate for assessing the CDT error types, we examined the relationships between each error type on the CDT and rCBF.Results:
Total score on the CDT was positively correlated with rCBF in the left posterior middle temporal lobe. We also found relationships between the error “non-existence of number 2, or not pointing toward number 2” and the left frontal lobe; the error “uneven number spacing” and the bilateral frontal lobe; “deviation of the clock center” and the left frontal lobe; “missing numbers” and the right parietal lobe; “uneven number distance from edge” and the right parietal and the temporal lobes; “same length hands” and the bilateral temporal lobe; and “unclosed circle” and the left temporal lobe.Conclusions:
Each error type on the CDT appears to relate to a different brain region. These findings will be useful in the understanding of CDT performances and the underlying neuropsychological pathology. Geriatr Gerontol Int 2016; 16: 777–784.