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Lewy body dementia (LBD) is a common type of dementia — a syndrome involving a decline in cognitive ability severe enough to interfere with someone’s ability to function. Dementia can result from several diseases and can affect thinking, movement, behavior, and other aspects of daily life.
LBD is an umbrella term for two related types of dementia: dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD). Although these conditions share many symptoms and underlying features, they differ in when certain symptoms appear and how the disorder develops.
In this article, we’ll discuss the seven stages of LBD progression, what causes LBD, common symptoms, and what to expect if a loved one is living with LBD.
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LBD can affect people differently. Symptoms may not always progress in a predictable order. However, the seven stages of LBD provide a map of how symptoms are likely to change over time.
LBD is among the most common types of progressive dementia — second only to Alzheimer’s disease. However, estimates of the number of people affected vary depending on the population studied and how dementia types are classified.
For example, in one review of 22 studies, the prevalence (number of people diagnosed) of DLB ranged from 0.3 percent to 24.4 percent of all people with dementia, depending on the study. The review authors concluded that rates of DLB increase with age.
LBD isn’t fully understood, but it’s linked to a buildup of Lewy bodies in the brain. Lewy bodies are clumps of a protein called alpha-synuclein.
Normally, alpha-synuclein protein is found throughout the brain and plays a role in how neurons (nerve cells) work and communicate. But when the protein misfolds and builds up, it can form Lewy bodies that damage brain cells and cause them to die.
The most significant difference between the two types of LBD — dementia with Lewy bodies and Parkinson’s disease dementia — is when dementia develops. In people with DLB, dementia occurs before or around the same time as movement symptoms. PDD develops after someone has already been living with the movement symptoms of Parkinson’s disease for some time.
But what causes these Lewy bodies to form in the first place? Researchers believe that someone’s genetics (inherited traits) may influence their risk of developing LBD.
Research has identified several genes that may be associated with LBD, including:
GBA1, which helps to break down cellular waste, has been linked to an increased risk of developing LBD. Research suggests that this gene also has a strong effect on how the disease develops.
The APOE ε4 — a variant of the APOE gene that makes the protein apolipoprotein E — is linked to an increased risk of DLB and Alzheimer’s disease. However, it hasn’t been linked to a higher risk of PDD. Changes in SNCA, the gene involved in making alpha-synuclein, have also been linked to LBD.
Although having one of these genetic risk factors may increase your risk of developing LBD, it doesn’t guarantee that you will. More research is needed to understand the complicated role of these genes.
There are many possible signs and symptoms of LBD. The primary sign is cognitive impairment. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines cognitive impairment as a decline in one or more areas, including:
People with difficulties in these areas might be forgetful or have trouble paying attention or solving problems. They may also have difficulty learning new facts or skills, struggle to speak or form sentences, or experience behavioral changes.
Symptoms can range from mild to severe and must significantly impair a person’s day-to-day functioning to support a diagnosis of dementia.
People with DLB and PDD may have symptoms that develop at different times.
Along with cognitive impairment, four core features characterize DLB:
Other symptoms can also support a DLB diagnosis, such as sensitivity to antipsychotic medications, repeated falls, or mood changes like depression or anxiety.
PDD symptoms are similar, but their timing is different. The important difference is that in PDD, parkinsonian symptoms start before cognitive symptoms and dementia.
Once dementia develops in someone with Parkinson’s disease (resulting in PDD), there are no clinical or biological differences that can reliably distinguish it from DLB.
Diagnosing LBD can be challenging. DLB often looks like Alzheimer’s disease, while PDD can be hard to recognize in people who already have Parkinson’s disease.
Diagnosis of LBD is primarily based on symptoms, medical history, cognitive tests, and physical and neurological exams. A neurologist may also use questionnaires and rating scales to assess someone’s symptoms.
Doctors don’t usually use imaging tests like magnetic resonance imaging (MRI) or laboratory tests to make an LBD diagnosis. However, these types of tests may help rule out other causes or provide supportive evidence. Positron emission tomography (PET) or single photon emission computed tomography (SPECT) scans may also help doctors make a diagnosis.
Additionally, the presence of certain biomarkers, such as alpha-synuclein, can strengthen an LBD diagnosis.
The timing of dementia and parkinsonism is key to distinguishing DLB from PDD. Dementia that develops before or around the same time as parkinsonism supports a diagnosis of DLB. Dementia that starts later, after Parkinson’s disease has been diagnosed, is more likely due to PDD.
Several treatments, including medications and nondrug options, can help improve the symptoms of LBD.
Cholinesterase inhibitors can’t cure dementia. But for some people, these medications can help stabilize or improve cognitive and behavioral symptoms.
Cholinesterase inhibitors help increase the amount of important chemicals called neurotransmitters in the brain, which can help with memory and daily functioning. In one study, people with DLB who were treated with cholinesterase inhibitors had higher scores on cognitive tests over time than those who were untreated.
Side effects of these medications may include diarrhea, nausea, vomiting, and reduced appetite.
Another class of drugs, called N-methyl-D-aspartate antagonists, includes memantine. Memantine may provide some benefit for cognitive symptoms in people with DLB or PDD. However, evidence of the drug’s effectiveness is mixed.
People with LBD may experience a sleep disorder called REM sleep behavior disorder. Sedatives like clonazepam or melatonin (a sleep aid hormone) can sometimes help treat this condition.
Other more severe symptoms of LBD, such as changes in alertness (zoning out), agitation, and severe confusion, can be challenging to treat. Doctors must first rule out whether other causes like infection or medications could be triggering these symptoms.
In some cases, to manage psychotic symptoms associated with LBD, doctors may recommend a low dose of quetiapine or clozapine, both atypical antipsychotic drugs.
However, people with LBD can be unusually sensitive to other antipsychotic medications, such as haloperidol and olanzapine. These medications can worsen movement symptoms or cause other side effects and are generally avoided in people with LBD.
The U.S. Food and Drug Administration (FDA) has also approved pimavanserin (Nuplazid) for hallucinations and delusions associated with Parkinson’s disease.
Other therapies and resources, such as support groups, can help improve the quality of life for people with LBD and their caregivers. These nondrug options include:
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@A MyParkinsonsTeam Member, I sympathize with you regarding those losses you never expected; math isn’t as much of a loss because I wasn’t that great at it, especially Algebra, but there are other… read more
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