Do visuospatial and constructional disturbances differentiate frontal variant of frontotemporal dementia and Alzheimer's disease? an experimental study of a clinical belief.

BACKGROUND

In recent years several attempts have been made to distinguish frontotemporal dementia (FTD) from Alzheimer's disease (AD) on neuropsychological grounds; in particular, it has been suggested that FTD patients show spared spatial abilities with respect to AD patients.

OBJECTIVE

We aimed at verifying whether patients with the frontal variant of frontotemporal dementia (fv-FTD) and AD patients perform differently on visuospatial and constructional tasks.

METHODS

We assessed a wide range of visuospatial abilities and provided a qualitative analysis of constructional performances in 14 fv-FTD patients and 11 AD patients, matched for general cognitive abilities.

RESULTS

The two groups of patients achieved similar scores on two copying tasks, presented similar drawing procedures in copying Rey complex figure and made a similar quantitative and qualitative pattern of errors in copying simple geometrical drawings. Moreover, no significant difference was found between fv-FTD and AD patients on a specific battery for visuospatial abilities.

CONCLUSIONS

Our data and a review of the literature suggest that basic visuospatial and constructional skills cannot be taken as a reliable diagnostic criterion for distinguishing fv-FTD and AD at a mild to moderate disease stage and that the clinical belief of spared spatial abilities in fv-FTD has to be referred to the lack of topographic disorientation in comparison to AD.