A Longitudinal Study of Neurocognition in Dementia with Lewy Bodies Compared to Alzheimer's Disease.

Monica H Breitve,Arvid Rongve,Minna J Hynninen,Luiza J Chwiszczuk,Kolbjørn Brønnick,Bjørn H Auestad,Dag Aarsland

doi:10.3389/fneur.2018.00124

Abstract

There are relatively few longitudinal studies on the differences in cognitive decline between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), and the majority of existing studies have suboptimal designs. We investigated the differences in cognitive decline in AD compared to DLB over 4 years and cognitive domain predictors of progression. In a longitudinal study, 266 patients with first-time diagnosis of mild dementia were included and followed annually. The patients were tested annually with neuropsychological tests and screening instruments [MMSE (Mini-Mental Status Examination), Clinical Dementia Rating (CDR), the second edition of California Verbal Learning Test (CVLT-II), Trail Making Test A & B (TMT A & B), Stroop test, Controlled Oral Word Associations Test (COWAT) animal naming, Boston Naming Test, Visual Object and Space Perception Battery (VOSP) Cubes and Silhouettes]. Longitudinal analyses were performed with linear mixed effects (LME) models and Cox regression. Both specific neuropsychological tests and cognitive domains were analyzed. This study sample comprised 119 AD and 67 DLB patients. In TMT A, the DLB patients had a faster decline over 4 years than patients with AD (p = 0.013). No other longitudinal differences in specific neuropsychological tests were found. Higher executive domain scores at baseline were associated with a longer time to reach severe dementia (CDR = 3) or death for the total sample (p = 0.032). High or low visuospatial function at baseline was not found to be associated with cognitive decline (MMSE) or progression of dementia severity (CDR) over time. Over 4 years, patients with DLB had a faster decline in TMT A than patients with AD, but this should be interpreted cautiously. Beyond this, there was little support for faster decline in DLB patients neuropsychologically than in AD patients.

Highlights

There are relatively few longitudinal studies on the differences in cognitive decline between Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB), and the majority of existing studies have suboptimal designs
We found that visuoconstructional functions in DLB were worse than in AD, but we did not find any differences between AD and DLB regarding visuoperception [14]
There were no significant differences between the groups in age, education, depression, Mini-Mental Status Examination (MMSE), and Clinical Dementia Rating (CDR) scores at baseline

Summary

Introduction

There are relatively few longitudinal studies on the differences in cognitive decline between Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB), and the majority of existing studies have suboptimal designs. Previous longitudinal studies have limited evidence base mostly due to methodological weaknesses when addressing the rate of progression of cognitive decline in DLB as compared to AD, and the data are still inconclusive. 6 of 18 studies included in our systematic review and meta-analysis reported significant differences in the rate of cognitive decline between these two conditions. Three studies reported a faster cognitive decline on Mini-Mental Status Examination (MMSE) in patients with mixed DLB and AD compared to pure forms. The meta-analysis of six studies reporting MMSE scores found no significant difference in annual decline between DLB and AD [7]. Patients with mixed AD and DLB were shown to decline faster than AD or DLB, and in the last one, they found some indications of a faster decline in DLB than in AD and Parkinson’s disease dementia (PDD) [9, 10]

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