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Dynamic Functional Connectivity Changes in Dementia with Lewy Bodies and Alzheimer's Disease

36 Pages Posted: 15 Oct 2018 First Look: Under Review

See all articles by Julia Schumacher

Julia Schumacher

University of Newcastle - Institute of Neuroscience

Luis R. Peraza

University of Newcastle - Institute of Neuroscience

Michael Firbank

University of Newcastle - Institute of Neuroscience

Alan J. Thomas

University of Newcastle - Institute of Neuroscience

Marcus Kaiser

University of Newcastle - Institute of Neuroscience

Peter Gallagher

University of Newcastle - Institute of Neuroscience

John T. O’Brien

University of Cambridge - Department of Psychiatry

Andrew M. Blamire

University of Newcastle - Institute of Cellular Medicine

John-Paul Taylor

University of Newcastle - Institute of Neuroscience

Abstract

We studied the dynamic functional connectivity profile of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) compared to controls, how it differs between the two dementia subtypes, and a possible relation between dynamic connectivity alterations and temporally transient clinical symptoms in DLB. Resting state fMRI data from 31 DLB, 29 AD, and 31 healthy control participants were analysed using dual regression to determine between-network functional connectivity. Subsequently, we used a sliding window approach followed by k-means clustering and dynamic network analyses to study dynamic functional connectivity. Dynamic connectivity measures that showed significant group differences were tested for correlations with clinical symptom severity. Our results show that AD and DLB patients spent more time than controls in sparse connectivity configurations with absence of strong positive and negative connections and a relative isolation of motor networks from other networks. Additionally, DLB patients spent less time in a more strongly connected state and the variability of global brain network efficiency was reduced in DLB compared to controls. There were no significant correlations between dynamic connectivity measures and clinical symptom severity. An inability to switch out of states of low inter-network connectivity into more highly and specifically connected network configurations might be related to the presence of dementia in general as it was observed in both AD and DLB. In contrast, the loss of global efficiency variability in DLB might indicate the presence of an abnormally rigid brain network and the lack of economical dynamics, factors which could contribute to cognitive slowing and an inability to respond appropriately to situational demands.

Suggested Citation

Schumacher, Julia and Peraza, Luis R. and Firbank, Michael and Thomas, Alan J. and Kaiser, Marcus and Gallagher, Peter and O’Brien, John T. and Blamire, Andrew M. and Taylor, John-Paul, Dynamic Functional Connectivity Changes in Dementia with Lewy Bodies and Alzheimer's Disease (October 11, 2018). NICL-18-895, Available at SSRN: https://ssrn.com/abstract=3264910 or http://dx.doi.org/10.2139/ssrn.3264910

Julia Schumacher (Contact Author)

University of Newcastle - Institute of Neuroscience ( email )

5 Barrack Road
Newcastle, NE1 7RU
United Kingdom

Luis R. Peraza

University of Newcastle - Institute of Neuroscience

5 Barrack Road
Newcastle, NE1 7RU
United Kingdom

Michael Firbank

University of Newcastle - Institute of Neuroscience ( email )

5 Barrack Road
Newcastle, NE1 7RU
United Kingdom

Alan J. Thomas

University of Newcastle - Institute of Neuroscience

5 Barrack Road
Newcastle, NE1 7RU
United Kingdom

Marcus Kaiser

University of Newcastle - Institute of Neuroscience

5 Barrack Road
Newcastle, NE1 7RU
United Kingdom

Peter Gallagher

University of Newcastle - Institute of Neuroscience

5 Barrack Road
Newcastle, NE1 7RU
United Kingdom

John T. O’Brien

University of Cambridge - Department of Psychiatry

Herchel Smith Bldg
Robinson Way
Cambridge, CB2 0SZ
United Kingdom

Andrew M. Blamire

University of Newcastle - Institute of Cellular Medicine

Framlington Place
Newcastle upon Tyne, NE2 4HH
United Kingdom

John-Paul Taylor

University of Newcastle - Institute of Neuroscience

5 Barrack Road
Newcastle, NE1 7RU
United Kingdom

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