Phenotypic differences based on staging of Alzheimer's neuropathology in autopsy-confirmed dementia with Lewy bodies

Guerry M Peavy; Steven D Edland; Belinda M Toole; Lawrence A Hansen; Douglas R Galasko; Ann M Mayo

doi:10.1016/j.parkreldis.2016.07.008

Phenotypic differences based on staging of Alzheimer's neuropathology in autopsy-confirmed dementia with Lewy bodies

Parkinsonism Relat Disord. 2016 Oct:31:72-78. doi: 10.1016/j.parkreldis.2016.07.008. Epub 2016 Jul 21.

Authors

Guerry M Peavy¹, Steven D Edland², Belinda M Toole³, Lawrence A Hansen⁴, Douglas R Galasko⁵, Ann M Mayo³

Affiliations

¹ Department of Neurosciences, University of California, San Diego, United States. Electronic address: gpeavy@ucsd.edu.
² Department of Neurosciences, University of California, San Diego, United States; Department of Family Medicine and Public Health, University of California, San Diego, United States.
³ Hahn School of Nursing and Health Science, University of San Diego, United States.
⁴ Department of Neurosciences, University of California, San Diego, United States; Department of Pathology, University of California, San Diego, United States.
⁵ Department of Neurosciences, University of California, San Diego, United States.

Abstract

Introduction: The goal was to compare subgroups of dementia with Lewy Bodies (DLB) using neuropathological measures to differentiate 'pure' Lewy body (LB) dementia from 'mixed' DLB [co-occurring LB and Alzheimer's disease (AD) pathology] to facilitate diagnostic decision-making and future development of interventions based on predicted type(s) of neuropathology. Studies comparing these groups are rare relative to those differentiating 'pure' AD and all-cause DLB, and are limited by insufficient sample size, brief cognitive batteries, and/or absence of autopsy confirmation. To address these limitations, we assessed cognition and other features in a large, autopsy-confirmed DLB sample using an extensive neuropsychological battery.

Methods: Subjects from an AD research center autopsy series satisfying DLB pathology criteria were divided by an AD neuropathology index into DLB-LB (Braak stage 0-3) (n = 38) and DLB-AD (Braak stage 4-6) (n = 41) and compared on baseline variables from chart reviews and standardized measures.

Results: DLB-LB subjects were more impaired on visuospatial constructions, visual conceptual reasoning, and speed of processing, but less impaired on verbal memory and confrontation naming. All-type hallucinations occurred more frequently in DLB-LB, while delusions were common in both groups. Groups were similar in education and age at onset, and in baseline age, dementia severity, and functional capacity.

Conclusion: Salient findings included greater impairment on visual tasks and speed of processing and more frequent reports of all-type hallucinations in DLB-LB compared to DLB-AD. Relatively intact confrontation naming in DLB-LB and no differences in reported delusions were of note. Identifying differences in phenotypic features can improve prediction of underlying neuropathology.

Keywords: Alzheimer's disease; Behavior; Delusions; Dementia with Lewy bodies; Hallucinations; Neuropsychology; Parkinsonism.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Aged
Aged, 80 and over
Alzheimer Disease / pathology*
Alzheimer Disease / physiopathology*
Autopsy*
Cognition Disorders / diagnosis
Cognition Disorders / etiology*
Disability Evaluation
Female
Hallucinations / physiopathology
Humans
Lewy Body Disease / diagnostic imaging
Lewy Body Disease / pathology*
Lewy Body Disease / therapy
Male
Neuropathology
Neuropsychological Tests
Phenotype
Psychiatric Status Rating Scales

Grants and funding

P50 AG005131/AG/NIA NIH HHS/United States