Default network is not hypoactive in dementia with fluctuating cognition: an Alzheimer disease/dementia with Lewy bodies comparison

Franciotti, Raffaella; Falasca, Nicola Walter; Bonanni, Laura; Anzellotti, Francesca; Maruotti, Valerio; Comani, Silvia; Thomas, Astrid; Tartaro, Armando; Taylor, John‐Paul; Onofrj, Marco

doi:10.1016/j.neurobiolaging.2012.09.015

Cited by 94 publications

(139 citation statements)

References 57 publications

Supporting

Mentioning

117

Contrasting

Order By: Relevance

“…Nevertheless, our results of IC activities were consistent with neuroimaging evidence of RSN in DLB. Also, consistent with our assumption, previous fMRI studies showed preserved spatial configuration of RSNs in both DLB patients and healthy subjects [31, 32]. Second, age differences between DLB patients and healthy subjects can be a confounding factor for group comparison of EEG-RSN activities.…”

Section: Discussionsupporting

confidence: 88%

“…Recent studies on cortical activity using fMRI or eLORETA have revealed that cortical sources work together in distant regions even in the resting state and construct a set of resting state networks (RSNs), which subserve specific brain functions [20, 27-30]. In DLB, fMRI studies have reported that spatial configuration of RSNs was preserved but some activities of RSNs changed compared to healthy subjects [31, 32]. Importantly, these fMRI-RSN activities showed some correlations with brain functions in healthy subjects and dementia patients [33, 34].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

EEG Resting-State Networks in Dementia with Lewy Bodies Associated with Clinical Symptoms

et al. 2019

View full text Add to dashboard Cite

Background: Dementia with Lewy bodies (DLB) is characterized by progressive cognitive decline, fluctuating cognition, visual hallucinations, rapid eye movement sleep behavior disorder, and parkinsonism. DLB is the second most common type of degenerative dementia of all dementia cases. However, DLB, particularly in the early stage, is underdiagnosed and sometimes misdiagnosed with other types of dementia. Thus, it is of great interest investigating neurophysiological markers of DLB. Method: We introduced exact low-resolution brain electromagnetic tomography (eLORETA)-independent component analysis (ICA) to assess activities of 5 electroencephalography (EEG) resting-state networks (RSNs) in 41 drug-free DLB patients. Results: Compared to 80 healthy controls, DLB patients had significantly decreased activities in occipital visual and sensorimotor networks, where DLB patients and healthy controls showed no age dependences in all EEG-RSN activities. Also, we found correlations between all EEG-RSN activities and DLB symptoms. Specifically, decreased occipital α activity showed correlations with worse brain functions related to attention/concentration, visuospatial discrimination, and global cognition. Enhanced visual perception network activity correlated with milder levels of depression and anxiety. Enhanced self-referential network activity correlated with milder levels of depression. Enhanced memory perception network activity correlated with better semantic memory, visuospatial discrimination function, and global cognitive function as well as with severer visual hallucination. In addition, decreased sensorimotor network activity correlated with a better semantic memory. Conclusion: These results indicate that eLORETA-ICA can detect EEG-RSN activity alterations in DLB related to symptoms. Therefore, eLORETA-ICA with EEG data can be a useful noninvasive tool for sensitive detection of EEG-RSN activity changes characteristic of DLB and for understanding the neurophysiological mechanisms underlying this disease.

show abstract

Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

EEG Resting-State Networks in Dementia with Lewy Bodies Associated with Clinical Symptoms

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Similarly, previous studies reported either decreased [23], spared [24], or less impaired [25, 26] connectivity across DMN nodes during resting state in DLB patients compared to AD patients. Finally, regarding DMN functional connectivity in relation to other networks during the resting state, Galvin et al [27] found increased connectivity between the precuneus (a core region of the DMN) and regions in the dorsal attention network (DAN), along with decreased connectivity between the precuneus and the frontoparietal executive control networks and the visual cortices in DLB patients.…”

Section: Introductionsupporting

confidence: 64%

Functional Disconnectivity during Inter-Task Resting State in Dementia with Lewy Bodies

Chabran

Roquet

Gounot

et al. 2018

Dement Geriatr Cogn Disord

View full text Add to dashboard Cite

Aims: Limited research has been done on the functional connectivity in visuoperceptual regions in dementia with Lewy bodies (DLB) patients. This study aimed to investigate the functional connectivity differences between a task condition and an inter-task resting state condition within a visuoperceptual paradigm, in DLB patients compared with Alzheimer disease (AD) patients and healthy elderly control subjects. Methods: Twenty-six DLB, 29 AD, and 22 healthy subjects underwent a detailed clinical and neuropsychological examination along with a functional MRI during the different conditions of a visuoperceptual paradigm. Functional images were analyzed using group-level spatial independent component analysis and seed-based connectivity analyses. Results: While the DLB patients scored well and did not differ from the control and AD groups in terms of functional activity and connectivity during the task conditions, they showed decreased functional connectivity in visuoperceptual regions during the resting state condition, along with a temporal impairment of the default-mode network activity. Functional connectivity disturbances were also found within two attentional-executive networks and between these networks and visuoperceptual regions. Conclusion: We found a specific functional profile in the switching between task and resting state conditions in DLB patients. This result could help better characterize functional impairments in DLB and their contribution to several core symptoms of this pathology such as visual hallucinations and cognitive fluctuations.

show abstract

“…From our own group [148] we have recently demonstrated in AD, the overall activity of the DMN was lower than in controls and DLB, and that this reduction was mainly related to a decrease of activity in the Posterior Cingulate Cortex (PCC), while in DLB patients the engagement of the PCC was not altered. Additionally in DLB alterations were found in the interhemispheric left-right connection and in the connection between fronto-parietal areas in the right hemisphere.…”

Section: Further Modelsmentioning

confidence: 87%

Visual Hallucinations in PD and Lewy Body Dementias: Old and New Hypotheses

Onofrj

Taylor

Monaco

et al. 2013

Behavioural Neurology

View full text Add to dashboard Cite

Abstract. Visual Hallucinations (VH) are a common non-motor symptom of Parkinson's Disease (PD) and the Lewy body dementias (LBD) of Parkinson's disease with dementia (PDD) and Dementia with Lewy Bodies (DLB). The origin of VH in PD and LBD is debated: earlier studies considered a number of different possible mechanisms underlying VH including visual disorders, Rapid Eye Movement (REM) Sleep Intrusions, dysfunctions of top down or bottom up visual pathways, and neurotransmitter imbalance. More recently newer hypotheses introduce, among the possible mechanisms of VH, the role of attention networks (ventral and dorsal) and of the Default Mode Network (DMN) a network that is inhibited during attentional tasks and becomes active during rest and self referential imagery. Persistent DMN activity during active tasks with dysfunctional imbalance of dorsal and ventral attentional networks represents a new hypothesis on the mechanism of VH. We review the different methods used to classify VH and discuss reports supporting or challenging the different hypothetical mechanisms of VH.

show abstract

Default network is not hypoactive in dementia with fluctuating cognition: an Alzheimer disease/dementia with Lewy bodies comparison

Cited by 94 publications

References 57 publications

EEG Resting-State Networks in Dementia with Lewy Bodies Associated with Clinical Symptoms

EEG Resting-State Networks in Dementia with Lewy Bodies Associated with Clinical Symptoms

Functional Disconnectivity during Inter-Task Resting State in Dementia with Lewy Bodies

Visual Hallucinations in PD and Lewy Body Dementias: Old and New Hypotheses

Contact Info

Product

Resources

About