Background

Dementia with Lewy bodies (DLB) is a progressive, degenerative dementia characterized pathologically by cortical Lewy bodies and clinically by fluctuating cognition, well-formed visual hallucinations, and parkinsonism.^{[1, 2]}

Diagnostic criteria

The Fourth Report of the Dementia with Lewy Bodies Consortium defines diagnostic categories of “Probable” and “Possible” DLB by combining: central requirement (dementia), core clinical features, indicative biomarkers, and supportive (suggestive) features. The table below summarizes how many core features and/or biomarkers are needed for each category.^[1]

(Open Table in a new window)

Feature	Probable DLB	Possible DLB
Central requirement	Dementia	Dementia
Core clinical features	At least 2	Exactly 1
Indicative biomarkers	At least 1 (if only 1 core feature)	At least 1 (with no core features)
Supportive (“suggestive”) features	May be present (but not counted toward core or biomarker totals)

Core clinical features

Fluctuating cognition with pronounced variations in attention and alertness
Recurrent, well‐formed visual hallucinations
REM sleep behavior disorder (RBD; acting out dreams)
Spontaneous parkinsonism (bradykinesia with rigidity or rest tremor)

Indicative biomarkers

Reduced presynaptic dopamine transporter uptake in basal ganglia (DaT‐SPECT or PET)
Low myocardial ¹²³I‐MIBG uptake on cardiac scintigraphy
Polysomnographic confirmation of REM sleep without atonia

Supportive (“suggestive”) features

Severe neuroleptic sensitivity
Autonomic dysfunction (orthostatic hypotension, urinary incontinence)
Hallucinations in other modalities or delusions
Relative preservation of medial temporal lobe on MRI
Posterior‐predominant hypometabolism on FDG‐PET
EEG with prominent slow‐wave activity
Depression, apathy, or other neuropsychiatric symptoms

Next: Epidemiology

Epidemiology

According to the World Health Organization, 57 million people had dementia worldwide in 2021.^[3] DLB probably accounts for 10–20% of dementias. However, because the sensitivity and specificity of clinical diagnosis are poor, no good epidemiologic data on the incidence or prevalence of DLB are available.^[4]

The prevalence of DLB increases with age. There is limited literature on other specific risk factors.

Next: Epidemiology

Etiology

The etiology of DLB is not known. Symptoms and signs of DLB probably result, in part, from disruption of bidirectional information flow from the striatum to the neocortex, especially the frontal lobe. The cause is multifactorial. Altered levels of neuromodulators and/or neurotransmitters (eg, ACh, dopamine) influence the function of many neuronal circuits. In DLB, nonpyramidal cells in layers V and VI of the neocortex may contain LBs. Their function in neocortical information processing and in relaying data to subcortical regions probably is impaired. The etiology of fluctuations in cognitive function, which characterize DLB, is unknown.^[5]

Nagahama et al found that different types of psychotic symptoms in patients with DLB correlated with perfusion changes in different parts of the brain. Single-photon emission computed tomography (SPECT) scanning studies in 145 DLB patients revealed the following:^[6]

Visual hallucinations - Were related to hypoperfusion of the parietal and occipital association cortices
Misidentifications - Were related to hypoperfusion of the limbic-paralimbic structures
Delusions - Were related to hyperperfusion of the frontal cortices

Genetics

Rare cases of familial DLB have been reported. In familial DLB, pathogenic variants have been identified in the APOE ε4 allele, the SNCA gene (encoding α-synuclein on chromosome 4), and GBA (glucocerebrosidase).^[7]

Next: Epidemiology

Pathophysiology

Postmortem examinations in patients with Parkinson disease and those with DLB have demonstrated LBs in the substantia nigra and possibly in the locus ceruleus, dorsal raphe, substantia innominata, and dorsal motor nucleus of cranial nerve X (CNX, the vagus nerve). LBs are found in the neocortex of many patients with idiopathic Parkinson disease and in all patients with DLB. DLB overlaps parkinsonian dementias.

The primary constituent of LBs is alpha synuclein, a presynaptic protein, the function of which is unknown. Neurofilament proteins and ubiquitin are other important constituents of LBs. Numerous neurotransmitters, including acetylcholine (ACh), are diminished in DLB. The decrease in ACh may be more severe than in Alzheimer disease.

Mixed Alzheimer’s and Lewy‐body pathology

Up to 40% of patients with Alzheimer disease have concomitant LBs. These mixed cases are sometimes called the LB variant of Alzheimer disease (LBV-AD) and represent an overlap syndrome between DLB and Alzheimer disease. Signs and symptoms of LBV-AD also overlap between DLB and Alzheimer disease.^[8]

Next: Epidemiology

Prognosis

DLB is a disorder of inexorable progression. The rate of progression varies, and some investigators think that progression is faster than that of Alzheimer disease. Patients eventually die from complications of immobility, poor nutrition, and swallowing difficulties.^[9]

The following morbidities are associated with DLB:

With severe disease, patients may experience swallowing problems that can lead to impaired nutrition
Patients are at risk for falls because of impaired mobility and balance
Because of prolonged bed rest, patients are at risk for decubitus ulcers
Dysphagia and immobility also can lead to pneumonia

Clinical Presentation

[Guideline] McKeith IG, Boeve BF, Dickson DW, et al. Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium. Neurology. 2017 Jul 4. 89 (1):88-100. [QxMD MEDLINE Link].
Hemminghyth MS, Chwiszczuk LJ, Rongve A, Breitve MH. The Cognitive Profile of Mild Cognitive Impairment Due to Dementia With Lewy Bodies-An Updated Review. Front Aging Neurosci. 2020. 12:597579. [QxMD MEDLINE Link].
Dementia. World Health Organization. Available athttps://www.who.int/news-room/fact-sheets/detail/dementia. March 31, 2025; Accessed: June 6, 2025.
[Guideline] Expert Panel on Neurological Imaging, Moonis G, Subramaniam RM, Trofimova A, Burns J, Bykowski J, et al. ACR Appropriateness Criteria® Dementia. J Am Coll Radiol. 2020 May. 17 (5S):S100-S112. [QxMD MEDLINE Link].
Serra L, Cercignani M, Basile B, Spanò B, Perri R, Fadda L, et al. White Matter Damage along the Uncinate Fasciculus Contributes to Cognitive Decline in AD and DLB. Curr Alzheimer Res. 2012 Jan 23. [QxMD MEDLINE Link].
Nagahama Y, Okina T, Suzuki N, Matsuda M. Neural correlates of psychotic symptoms in dementia with Lewy bodies. Brain. 2009 Nov 17. [QxMD MEDLINE Link].
Bras J, Guerreiro R, Darwent L, et al. Genetic analysis implicates APOE, SNCA and suggests lysosomal dysfunction in the etiology of dementia with Lewy bodies. Hum Mol Genet. 2014 Dec 1. 23 (23):6139-46. [QxMD MEDLINE Link].
Ferman TJ, Smith GE, Boeve BF, et al. DLB fluctuations: specific features that reliably differentiate DLB from AD and normal aging. Neurology. 2004 Jan 27. 62(2):181-7. [QxMD MEDLINE Link].
Armstrong MJ. Advances in dementia with Lewy bodies. Ther Adv Neurol Disord. 2021. 14:17562864211057666. [QxMD MEDLINE Link].
McKeith IG, Rowan E, Askew K, et al. More severe functional impairment in dementia with lewy bodies than Alzheimer disease is related to extrapyramidal motor dysfunction. Am J Geriatr Psychiatry. 2006 Jul. 14(7):582-8. [QxMD MEDLINE Link].
Nelson PT, Kryscio RJ, Jicha GA, Abner EL, Schmitt FA, Xu LO, et al. Relative preservation of MMSE scores in autopsy-proven dementia with Lewy bodies. Neurology. 2009 Oct 6. 73(14):1127-33. [QxMD MEDLINE Link].[Full Text].
Sonnesyn H, Nilsen DW, Rongve A, Nore S, Ballard C, Tysnes OB, et al. High prevalence of orthostatic hypotension in mild dementia. Dement Geriatr Cogn Disord. 2009. 28(4):307-13. [QxMD MEDLINE Link].
Small GW. Neuroimaging as a diagnostic tool in dementia with Lewy bodies. Dement Geriatr Cogn Disord. 2004. 17 Suppl 1:25-31. [QxMD MEDLINE Link].
Walker RW, Walker Z. Dopamine transporter single photon emission computerized tomography in the diagnosis of dementia with Lewy bodies. Mov Disord. 2009. 24 Suppl 2:S754-9. [QxMD MEDLINE Link].
Lim SM, Katsifis A, Villemagne VL, Best R, Jones G, Saling M, et al. The 18F-FDG PET cingulate island sign and comparison to 123I-beta-CIT SPECT for diagnosis of dementia with Lewy bodies. J Nucl Med. 2009 Oct. 50(10):1638-45. [QxMD MEDLINE Link].
Brooks DJ. Imaging amyloid in Parkinson's disease dementia and dementia with Lewy bodies with positron emission tomography. Mov Disord. 2009. 24 Suppl 2:S742-7. [QxMD MEDLINE Link].
Villemagne VL, Okamura N, Pejoska S, Drago J, Mulligan RS, Chételat G, et al. Differential Diagnosis in Alzheimer's Disease and Dementia with Lewy Bodies via VMAT2 and Amyloid Imaging. Neurodegener Dis. 2012 Jan 17. [QxMD MEDLINE Link].
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Table 1

Table 1

Feature	Probable DLB	Possible DLB
Central requirement	Dementia	Dementia
Core clinical features	At least 2	Exactly 1
Indicative biomarkers	At least 1 (if only 1 core feature)	At least 1 (with no core features)
Supportive (“suggestive”) features	May be present (but not counted toward core or biomarker totals)

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