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A systematic literature review of fMRI and EEG resting-state functional connectivity in Dementia with Lewy Bodies: Underlying mechanisms, clinical manifestation, and methodological considerations.

Accepted version
Peer-reviewed

Type

Article

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Authors

Kucikova, Ludmila 
Kalabizadeh, Hoda 
Motsi, Kimberly Gamuchirai 
Rashid, Sidrah 
O'Brien, John T 

Abstract

Previous studies suggest that there may be important links between functional connectivity, disease mechanisms underpinning the Dementia with Lewy Body (DLB) and the key clinical symptoms, but the exact relationship remains unclear. We performed a systematic literature review to address this gap by summarising the research findings while critically considering the impact of methodological differences on findings. The main methodological choices of fMRI articles included data-driven, seed-based or regions of interest approaches, or their combinations. Most studies focused on examining large-scale resting-state networks, which revealed a consistent decrease in connectivity and some associations with non-cognitive symptoms. Although the inter-network connectivity showed mixed results, the main finding is consistent with theories positing disconnection between visual and attentional areas of the brain implicated in the aetiology of psychotic symptoms in the DLB. The primary methodological choice of EEG studies was implementing the phase lag index and using graph theory. The EEG studies revealed a consistent decrease in connectivity on alpha and beta frequency bands. While the overall trend of findings showed decreased connectivity, more subtle changes in the directionality of connectivity were observed when using a hypothesis-driven approach. Problems with cognition were also linked with greater functional connectivity disturbances. In summary, connectivity measures can capture brain disturbances in the DLB and remain crucial in uncovering the causal relationship between the networks' disorganisation and underlying mechanisms resulting in psychotic, motor, and cognitive symptoms of the DLB.

Description

Keywords

Dementia with Lewy Body, EEG, Functional connectivity, Imaging methodology, MRI, Resting-state networks, Humans, Lewy Body Disease, Magnetic Resonance Imaging, Brain, Cognition, Electroencephalography, Alzheimer Disease

Journal Title

Ageing Res Rev

Conference Name

Journal ISSN

1568-1637
1872-9649

Volume Title

Publisher

Elsevier BV
Sponsorship
The research was supported by the NIHR Sheffield Biomedical Research Centre (BRC) / NIHR Sheffield Clinical Research Facility (CRF).