Lewy Body Dementia: What Caregivers Need to Know

By Heather Robbins, Founder — Robbins Nest Alliance

Lewy body dementia is the second most common neurodegenerative dementia after Alzheimer's disease. It is also one of the most misdiagnosed. Caregivers frequently spend years watching symptoms that do not fit neatly into any category fluctuating cognition, visual hallucinations, movement problems, sleep disorders before anyone puts a name to it.

This article covers what Lewy body dementia is, how it presents, why it gets missed, and what the evidence says about managing it. All sources are peer-reviewed.

What Is Lewy Body Dementia

Lewy body dementia (LBD) is an umbrella term covering two related diagnoses: dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Both involve the same underlying pathology, abnormal deposits of a protein called alpha-synuclein that form inside nerve cells. These deposits are called Lewy bodies, named after the neurologist who first described them.

The distinction between DLB and PDD is largely about timing. In DLB, cognitive symptoms appear first or alongside motor symptoms. In PDD, a Parkinson's disease diagnosis comes first and dementia develops later typically more than a year after motor symptoms begin. The biological process driving both is the same.

Research published in ScienceDirect confirmed that LBD is vastly underdiagnosed, with a significant gap between clinical diagnosis rates and neuropathological findings at autopsy. Many people living with LBD are diagnosed with Alzheimer's disease or Parkinson's disease instead, sometimes for years.

Why Misdiagnosis Is So Common

LBD shares features with both Alzheimer's disease and Parkinson's disease, which makes it easy to miss and easy to misclassify. A 2024 study in Alzheimer's and Dementia found that diagnosis of LBD takes twice as long as Alzheimer's disease from the time of referral.

This matters beyond the frustration of a long diagnostic road. Certain medications commonly used in other dementias are dangerous in LBD. Antipsychotic medications,  particularly typical antipsychotics, can cause severe, sometimes fatal reactions in people with Lewy body dementia. Getting the diagnosis right is not just academic. It is a safety issue.

Core Clinical Features

Current diagnostic criteria for probable DLB require the presence of dementia plus at least two of four core features, or one core feature plus one indicative biomarker feature.

The four core clinical features are:

• Fluctuating cognition. Pronounced variations in attention and alertness, not gradual decline, but day-to-day or even hour-to-hour swings. The person may seem nearly normal at one point and severely confused a few hours later. This is one of the most distinctive and most confusing features for caregivers.
• Recurrent visual hallucinations. Typically well-formed and detailed, people, animals, or objects that are not there. Unlike hallucinations in some other conditions, the person with LBD may be partially aware that what they are seeing is not real, particularly early in the disease.
• REM sleep behavior disorder (RBD). During REM sleep, the normal muscle paralysis that prevents acting out dreams is absent. The person physically acts out their dreams, talking, shouting, punching, kicking. RBD can precede cognitive symptoms by years and is now recognized as a significant prodromal marker for LBD.
• Parkinsonism. Motor features including slowness of movement, muscle rigidity, shuffling gait, and postural instability. Tremor is less prominent in LBD than in classic Parkinson's disease.

Additional Features Caregivers Should Know

Beyond the four core features, LBD commonly involves:

• Autonomic dysfunction. The automatic functions of the body, blood pressure regulation, heart rate, digestion, bladder control, are disrupted. Orthostatic hypotension (a drop in blood pressure upon standing that causes dizziness or fainting) is particularly common and is a significant fall risk.
• Sensitivity to neuroleptic medications. As noted above, antipsychotics carry serious risks in LBD. Any caregiver whose person is prescribed an antipsychotic should confirm with the prescribing physician that LBD has been ruled out or that the specific medication is safe for LBD.
• Depression and anxiety. These are common features of LBD, not simply reactions to the diagnosis.
• Loss of smell. Anosmia, reduced or absent sense of smell, is documented as an early risk factor and prodromal feature across LBD research.

Diagnosis

There is no single definitive test for LBD in living patients. Diagnosis is clinical, based on history, examination, and supporting tests.

Supportive diagnostic tools include:

• DaTscan (dopamine transporter imaging) shows reduced dopamine transporter uptake in the basal ganglia
• Polysomnography, sleep study that can confirm REM sleep behavior disorder
• Cardiac MIBG scintigraphy, cardiac imaging showing reduced postganglionic sympathetic innervation

Newer biomarker testing, specifically alpha-synuclein seeding amplification assays, can now detect Lewy body pathology in living patients with high reliability, though this testing is not yet standard in clinical practice as of 2024.

Management: What the Evidence Supports

There is no disease-modifying treatment for LBD. Management is symptomatic and supportive. Research published in The Lancet Neurology supports a multipronged approach combining pharmacological and non-pharmacological interventions targeting different symptom domains.

Cognitive symptoms. Cholinesterase inhibitors, the same class used in Alzheimer's disease, have shown benefit in LBD and are generally better tolerated than in Parkinson's disease dementia. Rivastigmine has the strongest evidence base.

Motor symptoms. Carbidopa-levodopa (the standard Parkinson's medication) can be used cautiously for motor features, though it may worsen hallucinations and psychosis in some patients.

Hallucinations and psychosis. This is where LBD management diverges most sharply from other dementias. Standard antipsychotics are contraindicated or require extreme caution. Quetiapine and clozapine are sometimes used at very low doses. The decision requires a specialist familiar with LBD.

REM sleep behavior disorder. Melatonin and low-dose clonazepam are the most commonly used approaches. Treating RBD also protects the sleep partner from physical injury during episodes.

Non-pharmacological care. Physical therapy for mobility and fall prevention, occupational therapy for daily living adaptations, and speech therapy for communication and swallowing difficulties all have documented benefit. Consistent routine and a stable, low-stimulation environment reduce the severity of fluctuations.

What This Means for Caregivers

LBD caregiving is widely documented as among the most demanding of all dementia caregiving experiences, in part because of the unpredictability of fluctuations, in part because of the physical demands of managing both cognitive and motor symptoms, and in part because of how long many families spend without the right diagnosis.

If you are caring for someone whose symptoms do not fit neatly into the Alzheimer's or Parkinson's box, if cognition fluctuates dramatically, if there are vivid hallucinations, if they act out their dreams at night, push for a specialist evaluation. A neurologist or geriatric psychiatrist with LBD experience makes a difference.

And if your person has been prescribed an antipsychotic, verify that the prescribing physician is aware of the LBD diagnosis. That conversation is worth having.

Related RNA Resources

• Nest Academy: Types of Dementia — Master Guide
• Brain Injury 101 — Full Educational Library
• Sundowning in Dementia: A Peer-Reviewed Caregiver Guide
• Veterans Blog: Dementia and Family Support

Peer-Reviewed Sources

1. Agarwal K, et al. Lewy body dementia: Overcoming barriers and identifying solutions. Alzheimer's and Dementia. 2024;20:2298–2308.
2. Outeiro TF, et al. Recent advances in Lewy body dementia: A comprehensive review. Experimental Neurology. 2022;339:113727.
3. Taylor JP, et al. New evidence on the management of Lewy body dementia. The Lancet Neurology. 2020;19:157–169.
4. Armstrong MJ. Lewy body dementias. Continuum (Minneapolis, Minn.). 2019;25(1):128–146.
5. Lewy Body Dementia Association. What Is LBD? lbda.org.
6. National Institute on Aging. Lewy Body Dementia: Causes, Symptoms, and Treatments. nia.nih.gov.

All sources are peer-reviewed or from established medical institutions. Robbins Nest Alliance does not provide medical advice. Consult your physician or care team for diagnosis and treatment decisions.