Lewy Body Dementia (LBD)

LBD, aka Dementia with Lewy Bodies (DLB), is a neurodegenerative disease. It’s the second most common type of dementia after Alzheimer’s. About 1.4 million people in the US and 10+ million worldwide are afflicted. 

Table of Contents

What is Lewy Body Dementia?

Let’s start with the name. Lewy is named after scientist Dr. Fritz Lewy. In 1912, Dr. Lewy was researching Parkinson’s Disease (PD). 

He noticed deceased patients had unusual clumps of proteins in their brains, called Lewy bodies. Back then, Lewy bodies were associated exclusively with PD.

Then in 1976, Dr. Kenji Kosaka first identified Lewy Body Dementia as a unique disease. Both PD and LBD have Lewy bodies as pathological signatures.

LBD is an elusive and lesser understood brain disease than Alzheimer’s and Parkinson’s. It causes a progressive decline in both cognitive and movement abilities.

According to the National Institute of Health, LBD is associated with the toxic accumulation of a misfolded protein called alpha-Synuclein in the brain.  

Normal Synuclein is a protein produced by most brain cells. Occasionally, these healthy proteins can change their structure and become what’s called misfolded proteins.

Misfolded Synuclein may induce other healthy Synuclein to misfold. As this process self-replicates and accumulates in the brain, they form Lewy bodies.

Lewy bodies cause brain cell death.

What Causes Lewy Body Dementia?

Why Lewy bodies form is still unknown. 

Misfolded protein build-up keeps the brain from making two important chemicals:

  • Acetylcholine affects cognitive functions, including memory and learning abilities.  
  • Dopamine affects movement, emotion, and sleep.

Risk Factors


The gene ApoE4 increases the risk for Alzheimer’s. It also increases the risk of Lewy Body Dementia.

Family History

People with two or more immediate family members with LBD have a higher risk. This can be due to epigenetic or genetic links. More research studies are needed to understand the connection better.  


Similar to other brain diseases, aging also increases the risk of LBD.


In short, massive cell death in the following brain regions triggers the disease.

  • Neocortex – People with LBD often experience confusion due to cell death in this region. It controls memory, associations, and learning.
  • Midbrain – Cell death in this region causes motor symptoms similar to people with Parkinson’s.

Furthermore, research studies found that over 50% of people living with late-stage LBD also show two other types of misfolded protein:

  • Abeta
  • Tau

Misfolded Abeta and Tau are known to be asscociated with Alzheimer’s.

Scientists and researchers have yet to crack the code on what causes normal proteins to misfold.

First Signs of Lewy Body Dementia

LBD initially presents as an atypical Alzheimer’s with motor control issues or atypical Parkinson’s with cognitive symptoms.

One striking early sign is visual hallucinations. There can also be sound, smell, or touch hallucinations.

Lewy Body Dementia Stages

Generally, LBD stages include:

Prodromal stage
Symptoms include sleep disorders, hallucinations, depression, and dizziness.

Symptoms often overlap with Alzheimer’s or Parkinson’s. These include memory loss, occasional disorientation, stiffness/tremors, and loss of balance.

Intermediate stage
Early-stage symptoms become more pronounced.

Symptoms advance to a stage where 24-hour care may be required. In addition, complications may lead to terminal illness.

Lewy Body Dementia Symptoms

Active Dreaming

Physically acting out dreams; punching, kicking, and yelling. As a result, falling out of bed often occurs. This condition is called REM sleep behavior disorder (RBD).


A condition associated with a lack of motivation and indifference to one’s surroundings. 


Struggling to differentiate what is real and what is not. For example, a person might believe others are out to get them when they are just trying to help.

Difficulty Concentrating

Adults often find concentration increasingly difficult as they age. But this is far more pronounced in people with LBD. For instance, they may be able to concentrate on a complex matter and yet, struggle with a simple task.


A growing, persistent feeling of sadness.

Fluctuating attention

Wide range of attention swings. These include bouts of drowsiness, prolonged periods of blank stares, long daytime naps, or jumbled speech.


Various kinds of hallucinations, including visual, audio, scent, and/or touch.


The human face has 43 muscles to help express emotions. Through the nervous system, the brain controls these muscles to respond accordingly. People with LBD often develop hypomimia, aka Parkinson’s mask – an expressionless face.

High Sensitivity to Medication

Extreme sensitivity to antipsychotic treatments. These drugs can elevate body tremors, muscle stiffness, further deteriorate mental sharpness, and worsen hallucinations.

Impairment of Visuospatial Ability

Our two eyes work together for triangulation to help judge direction and distance. People with Lewy Body Dementia lose this ability. As a result, even reaching for the remote can be difficult.

Loss of Balance

The diminishing ability to judge distance and depth causes balance loss. As a result, stumbles and falls happen more often, leading to broken/fractured bones, concussions, and more.

Personality Changes

These behavior and mood changes include:

  • Lost interest in life-long hobbies
  • Becoming repetitive
  • Lowered general emotional response

Shifting Symptoms

One of the startling characteristics is how quickly and randomly the symptoms shift. They can dramatically change from day to day, hour to hour, even minute to minute.

Mixed Symptoms

People with LBD (or Parkinson’s) have Lewy bodies in their brains. In addition, they may also develop plaques and tangles associated with Alzheimer’s.

The overlapping symptoms can make accurate diagnosis difficult. Here are some of the mixed symptoms:

Alzheimer's-like Symptoms

People with LBD undergo progressive cognitive changes that can be indistinguishable from Alzheimer’s. These symptoms include:

  • Diminished reasoning
  • Loss of logic
  • Decline of executive function
  • Memory loss
  • Hallucinations

Parkinson's-like Symptoms

People living with LBD also show Parkinson’s related movement symptoms including:

  • Rigid muscles
  • Movement disorders
  • A shuffling walk
  • Leaning toward one side
  • Sleep disorders
  • Autonomic changes affecting heart rate, blood pressure, and urinary incontinence

How is Lewy Body Dementia Diagnosed?

According to the NIH, the only definitive way to diagnose LBD is through autopsy.

A Long Diagnostic Journey

People with LBD go through a long diagnostic journey. The Lewy Body Dementia Association (LBDA) conducted an extensive survey. Nearly 1,000 caregivers participated, revealing these facts:

About 15% of patients saw at least five doctors before being accurately diagnosed.

  • On average, patients visited three doctors before receiving the correct diagnosis. 
  • 1 in 4 was correctly diagnosed within three months of symptom onset.
  • Only 23% were accurately diagnosed within a year.
  • For the other 50%, it took longer than one year for a correct diagnosis.

Overall, 10% of patients waited 3+ years to receive an accurate diagnosis.

Currently, doctors make a diagnosis after symptoms appear. As a result, people living with LBD undergo a long asymptomatic stage, in which brains damage occurs without detection. Consider the case of Robin Williams

Confirmation that Robin Williams had LBD came after his autopsy.

Our breakthrough SYNTap® Biomarker Test is poised to transform LBD diagnosis. 

Robin Williams

Confirmation that Robin Williams had LBD came after his autopsy.

Our breakthrough SYNTap® Biomarker Test is poised to transform LBD diagnosis. 

Diagnostic Challenges

According to the NIH, 50% of people with LBD are misdiagnosed.

Why has it been so challenging to diagnose LBD accurately in the past? Here are two key reasons:

  1. We could not detect misfolded Synuclein in the brain using conventional methods.
  2. Overlapping symptoms can make clinical diagnosis difficult.

Consider the following scenarios:

Initially misdiagnosed as Alzheimer's

A person shows memory loss and modest disruption of executive function. Doctors would likely diagnose Alzheimer’s.

Later that same person also shows motor or autonomic symptoms; doctors would most likely change to an LBD diagnosis.

Blog Featured Image - Abeta plague Alzheimer's
Assay About Parkinson’s disease

Initially misdiagnosed as Parkinson's

A person shows Parkinsonian motor issues. If there are no cognitive symptoms, doctors likely diagnose Parkinson’s.

If dementia signs appear after more than one year, doctors likely change the diagnosis to Parkinson’s Disease Dementia (PDD).

However, if the above scenario happens within one year, doctors likely change the diagnosis to Lewy Body Dementia.

Beginning of the End for LBD

The SYNTap Biomarker Test helps doctors diagnose LBD accurately. Through molecular diagnosis, we aim to accelerate the development of personalized medicine.

Lewy Body Dementia Treatment

Currently, no drug can cure LBD. However, some medicines aim at improving symptoms.

Certain medications have side effects. For example, antipsychotic treatments can exacerbate confusion, Parkinsonism, and sedation. Sometimes even death.

Due to these side effects, accurate diagnosis is essential.

LBD Care Team

People with Lewy Body Dementia may benefit from a cross-disciplinary care team including: 

  • A neurologist specializing in Alzheimer’s
  • A neurologist specializing in Parkinson’s
  • A psychiatrist for behavior problems
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