White matter lesion (WML) load and clock drawing test (CDT): a comparison of two diagnostic tools in dementias

Abstract

Introduction:

One of the signs of severity of a Vascular Dementia (VD) is white matter lesion load, although white matter lesions also occur in Alzheimer´s Dementia. These lesions reduce some cognitive and executive functions of the brain, that also affect the ability to draw a clock in CDT.

Here we would like to examine if there is a relation beetween WML load and severity of errors in the clock drawing test.

Material and methods

Patients (n = 236) of a memory clinic were examined clinically, neuropsychologically and neuroradiologically and differentiated in the following diagnostic groups according to ICD-10: cognitively healthy persons (XD, n=65), VD (n=56) and Alzheimer´s Disease (AD, n=115).

A large number of neuropsychological tests were done, one of them was the CDT, which was rated with a specially developed 8-point scale developed in our hospital instead of the 6-point scale established by Shulman.

Rating of the WML load was done according to a special 48- point score, also developed in our house.

Comparison of groups was done using descriptive statistics and analysis of variance.

Results:

For all the three groups we found a statistically significant correlation between WML load and CDT score on the p< 0,05 level.

Regarding the CDT score there was a highly significant correlation beetween XD/VD and XD/AD, but no correlation beetween VD/AD.

Conclusion:

CDT seems to be an interesting tool in estimating wml load in dementias.

The lack of discriminatin beetween VD/AD could be perhaps overcome with an even finer scale.