Visual cortex in dementia with Lewy bodies: Magnetic resonance
                        imaging study

Taylor, John‐Paul; Firbank, Michael; He, Jiabao; Barnett, Nicola; Pearce, Sarah; Livingstone, Anthea; Vuong, Quoc C.; McKeith, Ian G.; O’Brien, John T.

doi:10.1192/bjp.bp.111.099432

Cited by 76 publications

(70 citation statements)

References 43 publications

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“…Our results are therefore consistent with disrupted connectivity between the primary visual cortex and higher visual regions being associated with hallucinations. This is further supported by our previous finding that in an fMRI study of visual function the primary visual cortex activation was normal in DLB, whilst higher visual areas were abnormal, (Taylor et al 2012) and a recent MRI study found correlation between NPI hallucination score and reduced cortical thickness in the superior parietal region of DLB.…”

Section: Discussionsupporting

confidence: 68%

The relationship between hallucinations and FDG-PET in dementia with Lewy bodies

Firbank

Lloyd

O’Brien

2015

Brain Imaging and Behavior

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Visual hallucinations are common in dementia with Lewy bodies (DLB), although their etiology is unclear. This study aimed to investigate the relationship between severity and frequency of hallucinations and regional brain glucose metabolism. We performed brain FDG-PET scanning on 28 subjects with DLB (mean age 76). The neuropsychiatric index (NPI) was used to assess frequency and severity of hallucinations. We used the SPM package to investigate voxelwise correlations between NPI hallucination score (severity x frequency) and FDG uptake relative to the cerebellum. There was a bilateral medial occipital region where reduced FDG was associated with increased hallucination severity and frequency. We conclude that the reduced occipital metabolism frequently seen in DLB is associated with frequency and severity of visual hallucinations. Further studies are required to investigate whether this is the result of deficits in top-down or bottom-up visual processing pathways.

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Section: Discussionsupporting

confidence: 68%

The relationship between hallucinations and FDG-PET in dementia with Lewy bodies

Firbank

Lloyd

O’Brien

2015

Brain Imaging and Behavior

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“…In contrast, the few functional MRI studies on this topic reported a relative preservation of functional activity in lower visual areas, suggesting that the visuoperceptual impairment in these patients is rather related to disturbances in higher visual areas [13]. This hypothesis is supported by the results of other studies showing the absence of significant grey matter atrophy in the occipital lobe in DLB patients [14], and no difference in visual-cortical excitability compared to controls [15].…”

Section: Introductionsupporting

confidence: 63%

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

Chabran

Roquet

Gounot

et al. 2018

Dement Geriatr Cogn Disord

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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.

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“…Improved ways of measuring hallucinations will make it easier to track treatment response, while better understandings of the mechanisms which underlie hallucinations may open up new treatment avenues. In this regard, neuroimaging, neurophysiological and neuropathological/neurochemical studies have begun to provide powerful insights in the etiology of visual hallucinations [67][68][69][70][71]. For example, postmortem and neuroimaging studies in LBD patients have found that alterations in both nicotinic and muscarinic receptors are associated with visual hallucinations [45,71].…”

Section: Future Perspectivementioning

confidence: 99%

Advances In the Treatment of Visual Hallucinations In Neurodegenerative Diseases

Collerton

2013

Future Neurol.

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Treatment of visual hallucinations in neurodegenerative disorders is not well advanced. The complexity of underlying mechanisms presents a number of potential avenues for developing treatments, but also suggests that any single one may be of limited efficacy. Reducing medication, with the careful introduction of antidementia medication if needed, is the mainstay of current management. Antipsychotic medication leads to excessive morbidity and mortality and should only be used in cases of high distress that do not otherwise respond. Education, reduction of risk factors and psychological treatments have limited evidence of efficacy, but are unlikely to cause harm.

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Visual cortex in dementia with Lewy bodies: Magnetic resonance imaging study

Cited by 76 publications

References 43 publications

The relationship between hallucinations and FDG-PET in dementia with Lewy bodies

The relationship between hallucinations and FDG-PET in dementia with Lewy bodies

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

Advances In the Treatment of Visual Hallucinations In Neurodegenerative Diseases

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