Anatomy of visual hallucinations and fluctuations of consciousness in Lewy body diseases
type: CreativeWork
description: Lewy body diseases are characterized by parkinsonian disorders of movement and neuropsychiatric features of dementia, visual hallucinations and altered states of consciousness. The underlying neurobiological changes responsible for the psychiatric features are poorly understood. The integrative centre and key area for arousal, the thalamus, has not been assessed for neurodegeneration in relation to these perceptual deficits, and the brain activation patterns associated with visual hallucinations in non-demented patients have not been clearly established. This thesis aims to address these deficits in knowledge using two separate populations and methods. The first set of studies (Part one) utilizes post-mortem tissue to examine first the intralaminar and then the medial limbic thalamic nuclei across the spectrum of Lewy body diseases. Atrophy of these nuclei, atrophy of neurons, neuronal death and a-synuclein deposition were assessed and relationships with clinical variables tested. These studies found changes in several thalamic nuclei, some of which are associated with disease, and others associated with particular clinical features. Visual hallucinations, but not fluctuating consciousness, associated with atrophy of medial limbic thalamic nuclei. The second set of studies (Part two) firstly mapped cerebral blood flow in living patients with Parkinson's disease without dementia, in order to compare populations with and without visual hallucinations. A drug trial of a cholinesterase inhibitor in this population was then performed to determine clinical effect and the impact of this drug on cerebral perfusion. These studies identified occipital hypoperfusion in Parkinson's disease patients with visual hallucinations, and that increasing acetylcholine stopped the hallucinations in association with perfusion changes in limbic cortical regions. In fact, the perfusion changes in the parahippocampal and anterior cingulate cortices identified in Part two are likely to connec…
abstract: Lewy body diseases are characterized by parkinsonian disorders of movement and neuropsychiatric features of dementia, visual hallucinations and altered states of consciousness. The underlying neurobiological changes responsible for the psychiatric features are poorly understood. The integrative centre and key area for arousal, the thalamus, has not been assessed for neurodegeneration in relation to these perceptual deficits, and the brain activation patterns associated with visual hallucinations in non-demented patients have not been clearly established. This thesis aims to address these deficits in knowledge using two separate populations and methods. The first set of studies (Part one) utilizes post-mortem tissue to examine first the intralaminar and then the medial limbic thalamic nuclei across the spectrum of Lewy body diseases. Atrophy of these nuclei, atrophy of neurons, neuronal death and a-synuclein deposition were assessed and relationships with clinical variables tested. These studies found changes in several thalamic nuclei, some of which are associated with disease, and others associated with particular clinical features. Visual hallucinations, but not fluctuating consciousness, associated with atrophy of medial limbic thalamic nuclei. The second set of studies (Part two) firstly mapped cerebral blood flow in living patients with Parkinson's disease without dementia, in order to compare populations with and without visual hallucinations. A drug trial of a cholinesterase inhibitor in this population was then performed to determine clinical effect and the impact of this drug on cerebral perfusion. These studies identified occipital hypoperfusion in Parkinson's disease patients with visual hallucinations, and that increasing acetylcholine stopped the hallucinations in association with perfusion changes in limbic cortical regions. In fact, the perfusion changes in the parahippocampal and anterior cingulate cortices identified in Part two are likely to connec…
author: Brooks, Daniel
language: EN
keywords: Lewy body diseases,, Parkinson's disease,, Drug trial,
license: https://purl.org/coar/access_right/c_abf2
license: https://creativecommons.org/licenses/by-nc-nd/3.0/au/
date published: 2009
date modified: 2026-07-24T05:34:44Z
provider: University of New South Wales
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: UNSW, Sydney

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1959.4/50240

PropertyValue
property ID: DOI
value: 10.26190/unsworks/14950