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Query: UMLS:C0752347 (Dementia with Lewy bodies)
 1,653 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Newly proposed criteria for Lewy body dementia include alterations in consciousness. Lewy body dementia is also associated with a disturbance in cholinergic transmission; neocortical cholinergic deficits in this disorder are more extensive than in Alzheimer's disease and are correlated with symptoms commonly associated with delirium, such as visual hallucinations. The traditional view that derangements of the basal forebrain cholinergic system in Alzheimer's disease relate specifically to memory impairment is assessed in terms of a more general role for cortical acetylcholine in consciousness. This extends the concept that cortical acetylcholine enhances neuronal signal to noise ratio. It is suggested that muscarinic receptor activation in the cortex is involved in confining the contents of the discrete self-reported conscious "stream." In the absence of cortical acetylcholine, currently irrelevant intrinsic and sensory information, which is constantly processed in parallel at the subconscious level, enters conscious awareness. This is consistent with the ability of anti-muscarinic drugs administered medically, recreationally, or ritualistically to induce visual hallucinations and other perceptual disturbances. The hypothesis is explored through comparisons between muscarinic and nicotinic receptor psychopharmacology and between the pathology of the basal forebrain as opposed to pedunculopontine cholinergic systems in different diseases of the human brain affecting consciousness and cognition. The paradoxical effects of muscarinic receptor blockade to induce hallucinations and of REM sleep-associated cholinergic activation of the thalamus to induce dreaming may be related to the differential distribution and activity of muscarinic receptor subtypes or to the differing responses of intrinsic GABA neurons in cortex and thalamus.
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PMID:Acetylcholine and hallucinations: disease-related compared to drug-induced alterations in human consciousness. 854 52

The cholinergic system is one of the most important modulatory neurotransmitter systems in the brain and controls activities that depend on selective attention, which are an essential component of conscious awareness. Psychopharmacological and pathological evidence supports the concept of a 'cholinergic component' of conscious awareness. Drugs that antagonize muscarinic receptors induce hallucinations and reduce the level of consciousness, while the nicotinic receptor is implicated as being involved in the mechanism of action of general (inhalational) anaesthetics. In degenerative diseases of the brain, alterations in consciousness are associated with regional deficits in the cholinergic system. In Alzheimer's disease (AD), there is a loss of explicit (more than implicit) memory and hypoactivity of cholinergic projections to the hippocampus and cortex, while the visual hallucinations experienced by subjects with Dementia with Lewy bodies (DLB) are associated with reductions in neocortical ACh-related activity. In Parkinson's disease, the additional loss of pedunculopontine cholinergic neurones, which control REM (rapid eye movement) sleep or dreaming, is likely to contribute to REM abnormalities, which also occur in DLB. Widespread basal-forebrain and rostral brainstem cholinergic pathways, which include converging projections to the thalamus, appear to be located strategically for generating and integrating conscious awareness. Alleviation of a range of cognitive and non-cognitive symptoms by drugs that modulate the cholinergic system, which are being developed for the treatment of AD and related disorders, could be caused by changes in consciousness.
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PMID:Acetylcholine in mind: a neurotransmitter correlate of consciousness? 1054 30

A patient with REM sleep behavior disorder who subsequently developed probable Lewy body dementia is now reported to have a definite pathologic diagnosis of Lewy body dementia. Examination of brain revealed Lewy bodies as well as marked neuronal loss in brainstem monoaminergic nuclei-particularly locus coeruleus and substantia nigra-that inhibit cholinergic neurons in the pedunculopontine nucleus mediating atonia during REM sleep.
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PMID:The pathology of REM sleep behavior disorder with comorbid Lewy body dementia. 1111 32

Dementia with Lewy bodies (DLB) is the second most frequent neuropathologically diagnosed degenerative dementing illness. The clinical characteristics are progressive dementia, Parkinson syndrome, fluctuations of cognitive functions, vigilance and attention, visual hallucinations (usually detailed and well described), depression, REM-sleep behavior disorder, adverse responses to standard doses of neuroleptics, falls, syncopes, systematized delusions, and non-visual hallucinations. Mean age at disease onset ranges between 60 and 68 years. Male persons are more frequently affected than female. Disease duration is six to seven years. The differential diagnoses of DLB are dementia of the Alzheimer-type, Parkinson's disease, subcortical arteriosclerotic encephalopathy, progressive supranuclear palsy, multiple system atrophy, and, in rare cases, Creutzfeldt-Jakob disease. The genetic background of the disease is unclear. Magnetic resonance imaging and single photon emission tomography can contribute to the diagnosis. The disease is treated with L-dopa, atypical neuroleptics, acetylcholine esterase inhibitors, antihypotensive agents, and peripheral anticholinergic and alpha-receptor-blocking medicaments to improve neurogenic bladder dysfunction.
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PMID:[Dementia with Lewy bodies]. 1192 77

REM sleep behavior disorder (RBD) is a fascinating experiment in nature predicted by animal studies in 1964. A defining feature of REM sleep is active paralysis of all somatic musculature (sparing the diaphragm to permit respiration). RBD is characterized by the absence of REM atonia, permitting the appearance of dream-enacting behaviors. These oneiric behaviors may be violent or injurious. RBD typically affects men over the age of 50 years. Longitudinal follow-up has shown that the majority of individuals with RBD will eventually develop additional signs and symptoms of a number of neurodegenerative disorders, most notably one of the synucleinopathies (Parkinson's disease, dementia with Lewy body disease, multiple system atrophy, or pure autonomic failure), often after a prolonged interval lasting more than 10 years. RBD is also a common manifestation of narcolepsy. RBD may be induced by medications, especially the tricyclic antidepressants and serotonin-specific reuptake inhibitors. In most cases, clonazepam is a highly effective treatment.
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PMID:Pathophysiologic mechanisms in REM sleep behavior disorder. 1735 39

Hypocretin (orexin) cerebrospinal fluid (CSF) levels have been previously found normal or decreased in Dementia with Lewy bodies and Parkinson disease, two synucleinopathies commonly associated with excessive daytime sleepiness (EDS). We evaluated CSF hypocretin-1 levels in 15 patients with moderately severe multiple system atrophy (MSA), another synucleinopathy where sleep disorders occur frequently and EDS has been reported, performing additional electrophysiological studies in 5 of them to assess the presence of EDS and sleep onset REM (SOREM) periods. Despite relatively low sleep efficiencies in nocturnal sleep, mean sleep latencies in the Multiple Sleep Latency Test were normal with no SOREM periods. All patients had CSF hypocretin-1 levels in the normal range (>200 pg/mL) suggesting that the hypocretin system is not altered in MSA, at least in patients with a moderately severe disease.
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PMID:Cerebrospinal fluid hypocretin-1 levels in multiple system atrophy. 1765 46

Dementia with Lewy bodies (DLB) is the second most common form of neurodegenerative dementia. It is usually caused by a mixture of symptoms of Parkinson's and Alzheimer's disease leading to a significant impairment of nigro-striatal dopaminergic and baso-cortical cholinergic neurotransmission with typical clinical symptoms of a fluctuating course, hallucinations, parkinsonism, REM-sleep disorder and neuroleptic hypersensitivity. If the clinical presentation of DLB is uncharacteristic, the demonstration of reduced presynaptic striatal dopamine transporter (DaT) sites supports a suspicion of DLB and may lead to important therapeutic consequences. In these circumstances this evidence for compromised dopaminergic neurotransmission also indicates a significant cholinergic deficit: both require diligent therapeutic attention.
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PMID:[Dementia with Lewy bodies and reduced dopamine transporter binding indicates significant acetylcholine deficiency]. 1843 36

The neuropathology of human sleep remains an ill-defined issue. The data concerning the main structures of human brain areas involved, or supposed to be implicated, in sleep organisation are reviewed. Five levels of organisation can be schematically recognized: (i) the ascending arousal system, (ii) the non REM and REM systems (iii) regulated by hypothalamic areas, (iv) and the biological clock, (v) modulated by a number of "allostatic" influences. These are briefly described, with emphasis on the location of structures involved in humans, and on the recently revised concepts. Current knowledge on the topography of lesions associated with the main sleep disorders in degenerative diseases is recalled, including REM sleep behavior disorders, restless legs syndrome and periodic leg movements, sleep apneas, insomnia, excessive daily sleepiness, secondary narcolepsy and disturbed sleep-wake rhythms. The lesions of sleep related structures observed in early and late stages of four degenerative diseases are then reviewed. Two synucleinopathies (Lewy lesions associated disorders, including Parkinson's disease and Dementia with Lewy bodies, and Multiple System Atrophy) and two tauopathies (Progressive Supranuclear Palsy and Alzheimer's disease) are dealt with. The distribution of lesions usually found in affected patients fit with that expected from the prevalence of different sleep disorders in these diseases. This confirms the current opinion that these disorders depend on the distribution of lesions rather than on their biochemical nature. Further studies might throw insight on the mechanism of normal and pathological sleep in humans, counterpart of the increasing knowledge provided by animal models. Specially designed prospective clinicopathological studies including peculiar attention to sleep are urgently needed.
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PMID:[The neuropathology of sleep in human neurodegenerative diseases]. 1876 Apr 29

REM sleep behavior disorder is a unique parasomnia characterized by dream enactment behavior during REM sleep. Unless triggered by pharmacologic agents such as antidepressants, it is generally related to damage of pontomedullary brainstem structures. Idiopathic REM sleep behavior disorder (RBD) is a well-established risk factor for neurodegenerative disease. Prospective studies have estimated that at least 40-65% of patients with idiopathic RBD will eventually develop a defined neurodegenerative phenotype, almost always a 'synucleinopathy' (Parkinson's disease, Lewy Body dementia or multiple system atrophy). In most cases, patients appear to develop a syndrome with overlapping features of both Parkinson's disease and Lewy body dementia. The interval between RBD onset and disease onset averages 10-15 years, suggesting a promisingly large window for intervention into preclinical disease stages. The ability of RBD to predict disease has major implications for design and development of neuroprotective therapy, and testing of other predictive markers of synuclein-mediated neurodegeneration. Recent studies in idiopathic RBD patients have demonstrated that olfaction, color vision, severity of REM atonia loss, transcranial ultrasound of the substantia nigra, and dopaminergic neuroimaging can predict development of neurodegenerative disease.
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PMID:REM sleep behavior disorder: from dreams to neurodegeneration. 2201 18

REM sleep behavior disorder (RBD) is a parasomnia characterized by dream-enacting behavior and loss of muscle atonia during REM sleep. Idiopathic RBD occurs in the absence of any neurological disease or other possible cause, is male-predominant and its clinical course is generally chronic progressive. Secondary RBD may be related to neurodegenerative disorders such as multiple system atrophy, Parkinson's disease and Lewy body dementia. Recent long-term prospective studies have shown that 30% to 65% of patients with idiopathic RBD will eventually develop a neurodegenerative disorder with the rate of emergence depending on the length of the follow-up period. RBD may therefore be one of the earliest signs of and/or a long-term predictor for neurodegenerative disorders. Because RBD antecedes the development of these disorders by several years or decades, its recognition may enable the delay or prevention of neurodegenerative disorders through the early application of neuroprotective or disease-modifying therapies in the future.
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PMID:Idiopathic REM sleep behavior disorder as a long-term predictor of neurodegenerative disorders. 2319 80


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