Two distinct pathological substrates associated with MMSE-pentagons item deficit in DLB and AD

Dementia with Lewy Bodies (DLB) is characterized by a prominent deficit in visuospatial abilities. Visuospatial impairment is also detectable in the course of Alzheimer's dementia (AD). However, visuospatial impairment presents some differences in these two conditions, suggesting pathological involvement of distinct brain circuits. Recent studies applied a new method to score the Mini Mental State Examination (MMSE) pentagon copy subtest, namely the Qualitative Scoring Pentagon Test (QSPT), which is a sensitive measure of visuospatial abilities. Using [18F]fluorodeoxy-glucose positron emission tomography (FDG-PET), we assessed the relationship between in vivo brain metabolic dysfunction and visuospatial deficits, in terms of QSPT total value, in DLB and AD.