Science Simplified
Science Simplified: Why Lewy Body Dementia Can Be So Hard to Diagnose
October is Lewy Body Dementia Awareness Month, and for many families, awareness starts with a frustrating question: Why has it been so hard to get an answer?
An older caregiver survey gives a sense of that experience. In a web-based survey of 962 caregivers published in 2010, 78% reported that their loved one had received another diagnosis before Lewy body dementia was identified. Nearly a third reported waiting more than two years for the diagnosis.
Those figures describe the families who participated in that survey. They are not a current estimate for everyone living with LBD. But they capture something families still need to understand: this disease can be difficult to recognize, especially early on.
Why the symptoms can seem disconnected
Lewy body dementia, or LBD, is an umbrella term that includes dementia with Lewy bodies and Parkinson's disease dementia. The two are closely related; a key distinction is when cognitive changes appear in relation to established Parkinson's disease.
Both are associated with abnormal accumulations of a protein called alpha-synuclein. Normally, this protein helps nerve cells communicate. In LBD, it can misfold and accumulate inside nerve cells, forming deposits called Lewy bodies. These changes are linked to nerve-cell dysfunction and degeneration, although researchers are still working out exactly how the disease develops.
The effects can reach several systems involved in thinking, movement, sleep, mood, and automatic bodily functions such as blood pressure and digestion. The mix of symptoms, and when they appear, varies from person to person.
That is where the confusion can begin.
Someone may become slower or stiffer. Another person may have trouble following a conversation, judging distances, or organizing familiar tasks. Someone else may begin seeing people or animals that others cannot see.
In dementia with Lewy bodies, important diagnostic clues include fluctuations in attention and alertness, recurrent visual hallucinations, Parkinson-like movement changes, and REM sleep behavior disorder, acting out dreams during sleep. Not everyone has every feature, and they may not appear together. Memory loss can occur, but it is not always the most noticeable early change.
Why one appointment may not tell the whole story
Imagine someone who is clear and engaged during an appointment but struggled to follow a conversation that morning. Their partner also mentions restless nights, while dizziness on standing comes up at a different visit.
Each observation matters. Seeing how they fit together takes a careful history, including what the person and their care partners notice at home.
Some symptoms overlap with Alzheimer's disease, Parkinson's disease, psychiatric conditions, and other medical problems which can further complicate things. Alzheimer's-related brain changes can coexist with Lewy body disease, making the picture more complex.
Even experienced clinicians can find that challenging. Differences in familiarity with LBD and gaps in communication between providers can also contribute to delays. Diagnostic difficulty does not mean every missed diagnosis was unavoidable. It means a thorough assessment and follow-up matter. For families, the uncertainty can be exhausting. They are trying to understand changing explanations while helping someone they love get through the day.
What testing can and cannot tell us
There is currently no single blood test or brain scan that can diagnose LBD on its own. Doctors combine symptoms, medical history, examination findings, and testing. Specialized imaging, such as a dopamine transporter scan, can provide important supporting evidence.
Newer tests using spinal fluid or skin samples can also detect abnormal alpha-synuclein. These are meaningful advances but results still need clinical interpretation: evidence of an abnormal protein does not, by itself, establish which related disorder a person has or whether they have dementia.
What families can bring to the conversation
A brief dated record of changes can give the care team a clearer picture of life between appointments. Useful details include what happened, when it happened, how long it lasted, and whether it followed a medication change or illness.
Record specific observations: "She saw a child in the hallway at 4 p.m." or "He punched and shouted while asleep." Include the clearer days, too. Observations about fluctuations can be especially useful during an assessment. If questions remain, ask whether an evaluation by a neurologist, geriatrician, or memory clinic with experience in LBD would help.
Sudden or marked worsening should be assessed promptly rather than assumed to be part of dementia. An illness or another treatable problem may be contributing.
Where Vallige fits
At Vallige, our role is to support the everyday experience of people living with dementia and those who care for them. The Caregiver Journal offers space to reflect on the day, including what felt difficult and what went well. Daily Digest videos provide personalized content intended to support engagement and connection.
Vallige does not diagnose LBD. Families who want to document symptoms for a medical appointment should keep a clear record they can review and share with their care team. A journal may help organize observations, but it does not replace a clinical assessment.
If your family is still searching for answers, your observations deserve to be heard. Bring those observations to the appointment, ask how the different symptoms might fit together, and keep asking for clarification when the explanation feels incomplete.
A more accurate diagnosis can guide treatment and help families find support that fits their needs. You can learn more about Vallige's approach to comfort, care, and connection at vallige.com.
Sources
- Galvin JE, et al. Lewy body dementia: the caregiver experience of clinical care. Parkinsonism & Related Disorders. 2010;16(6):388–392. https://pubmed.ncbi.nlm.nih.gov/20434939/
- National Institute of Neurological Disorders and Stroke. Lewy Body Dementia. https://www.ninds.nih.gov/health-information/disorders/lewy-body-dementia
- McKeith IG, et al. Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium. Neurology. 2017;89(1):88–100. https://pmc.ncbi.nlm.nih.gov/articles/PMC5496518/
- Mastrangelo A, et al. Alpha-synuclein seed amplification assay longitudinal outcomes in Lewy body disease. https://pmc.ncbi.nlm.nih.gov/articles/PMC12129724/
- Gibbons CH, et al. Skin biopsy detection of phosphorylated α-synuclein in patients with synucleinopathies. JAMA. 2024;331(15):1298–1306. https://pubmed.ncbi.nlm.nih.gov/38506839/
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