The mild cognitive impairment stage of dementia with Lewy bodies and Parkinson disease: a comparison of cognitive profiles.

Abstract

BACKGROUND: Recent studies have demonstrated that structural and pathologic

changes are more severe in patients with dementia with Lewy bodies (DLB) than in

those with Parkinson disease with dementia (PDD). We investigated

neuropsychological characteristics of patients with mild cognitive impairment

(MCI) stage of DLB (DLB-MCI) and PD (PD-MCI) based on the hypothesis that the

pathologic differences between DLB and PDD can influence cognitive profiles in

the MCI stage of these diseases. METHODS: Baseline demographic characteristics

and neuropsychological data obtained from patients with DLB-MCI (n=20) and PD-MCI

(n=46) were compared. RESULTS: The patients with DLB-MCI showed poorer cognitive

performance in the Stroop, Go-No-Go, and semantic fluency tests compared with

those with PD-MCI. In addition, patients with DLB-MCI had lower scores on visual

and verbal memory performance and in the visuospatial domain compared with PD-MCI

patients. CONCLUSIONS: Our results demonstrate that patients with DLB-MCI have

more severe cognitive impairment in frontal executive, memory, and visuospatial

functions than those with PD-MCI. These data suggest that differences in

pathologic substrates between PDD and DLB may begin in the MCI stage of the 2

diseases and may lead to differences in cognitive profiles.