Lewy Body Dementia (LBD) is a degenerative disorder of the brain, characterized by a range of issues including cognitive decline, movement difficulties, behavioural changes, and mood disturbances.. Clumps of a protein called alpha-synuclein, a key protein also involved in Parkinson’s disease (PD), build up in parts of the brain associated with cognition and movement. These clumps, called “Lewy bodies”, eventually cause cell death, resulting in symptoms of dementia (National Institutes of Health, n.d.). Lewy bodies also disrupt neurotransmitters in the brain, namely dopamine and acetylcholine, which play important roles in movement, memory, and thinking (Heerema, 2023).

Lewy bodies are named after Dr. Friedrich Heinrich Lewy, who first described these structures that were discovered in the brains of patients who died with PD. Even though the first cases of Lewy Body Dementia were published in the 1960s, it took until the 1980s for the disease to start being recognized as its own medical condition (Rogers, 2020). Pathologists looking at post-mortem brains of people with dementia noticed that some of the brains did not have the classic features of Alzheimer’s disease (AD), which are plaques and tangles. These patients were found to have different features of dementia according to their clinical records, which researchers and pathologists found to be Lewy bodies.

After Alzheimer’s disease, Lewy Body Dementia is the second most common form of dementia. LBD is an umbrella term for two related clinical diagnoses: Parkinson’s disease dementia and dementia with Lewy bodies. While LBD and PD have overlap in their symptoms, they differ in one important way: the cognitive symptoms present themselves before movement symptoms in Lewy Body Dementia; the opposite is true for Parkinson’s disease (Heerema, 2023). If motor symptoms appear at the same time or within one year of dementia, the diagnosis is usually LBD. Additionally, not all people with LBD experience the motor symptoms of Parkinson’s (Alzheimer’s Association, n.d.).

 

Symptoms

LBD is commonly categorized into early, middle, and late stages based on the progression of the disease, though it is important to remember that everyone progresses in their unique way and no timeline is guaranteed. Additionally, unlike other forms of dementia, LBD’s progression is not always consistent or predictable; this may make it harder for medical professionals to provide an accurate prognosis (Heerema, 2023). Unfortunately, those with Lewy Body Dementia tend to have a shorter life expectancy than individuals with PD or Alzheimer’s disease (Armstrong et al., 2019).

Early Stages

The early stages of LBD may present as cognitive changes, including delusions (false, though unshakeable, beliefs) and hallucinations, which may be either auditory or visual. In fact, up to 80% of people with Lewy Body Dementia will experience profoundly vivid visual hallucinations, by, for example, seeing people or objects that are not physically present. Another 30% of those with LBD may experience auditory hallucinations (Heerema, 2023).

The early stages of this form of dementia may also involve sleep behaviour disorders, such as REM sleep behaviour disorder, where individuals act out their dreams. Individuals with LBD may also exhibit other sleep disturbances, such as an inability to fall asleep or excessive daytime sleepiness, as well as restless leg syndrome (National Institutes of Health, n.d.).

Middle Stages

In the middle stages of Lewy Body Dementia, symptoms may begin to resemble that of Parkinson’s disease. People with mid-stage LBD may have trouble with balance and coordination, communication and swallowing, and other motor functions. In this stage of the disease, cognition is also likely to continue to worsen, leading to shorter attention spans and increased confusion (Heerema, 2023).

Late Stages

This stage of Lewy Body Dementia is characterized by muscle rigidity and sensitivity to touch, as well as overall weakness. As a result of weakening muscles, those with late-stage LBD may aspirate their food and develop a serious complication called aspiration pneumonia, which can be fatal in some cases. The same muscles that make swallowing difficult also lead to problems speaking. People with late-stage LBD may develop a softer voice, and many may stop speaking altogether. Individuals are also likely to have difficulties with activities of daily living, such as eating, dressing, and using the washroom, and may require ongoing assistance (Heerema, 2023). While no one can predict how long each stage will last, the end stages of Lewy Body Dementia commonly last between two months and one year (Armstrong et al., 2019).

 

Other symptoms of Lewy Body Dementia include:

  • impaired thinking, such as loss of memory, executive function (processing information, planning), and ability to understand visual information and memories
  • trouble with problem solving (Heerema, 2023)
  • fluctuations in cognition, attention, or alertness – fluctuations in cognitive function are one of the distinctive characteristics of LBD, with individuals oscillating from functioning well one day, to experiencing significant memory loss the next day (Heerema, 2023)
  • mood disturbances
  • autonomic dysfunction, which can lead to changes in blood pressure, respiration rate, and bowel/bladder health (Heerema, 2023)

 

Causes

The cause of LBD is unknown. Genetic factors may play a role in some cases, but there is no clear pattern of inheritance. There is evidence that suggests that LBD is caused by the same mechanisms that cause PD. Unfortunately, we still do not know the cause of most cases of PD, nor do we know why some people develop PD, and others, LBD.

 

Diagnosis

Because of its varied symptoms, Lewy Body Dementia is often misdiagnosed as Alzheimer’s, Parkinson’s, or another condition, such as schizophrenia or delirium (National Institutes of Health, n.d.). The only way to confirm an LBD diagnosis is to examine the brain after death, as there are no medical tests that can diagnose the condition with complete accuracy.

Throughout life, the diagnosis of LBD is made based on the person’s symptoms. Doctors will often order blood tests or scans to exclude other illnesses that may cause similar symptoms, such as brain tumours or brain hemorrhages (Alzheimer’s Society UK, 2021). Doctors may also scan certain nerve cells in someone’s heart, as these cells change in similar ways as the nerve cells in the brain of someone with LBD (Alzheimer’s Society UK, 2021).

The following criteria are used to make a clinical diagnosis of LBD:

  • dementia developed during the course of the disease
  • specific difficulties with inattention, visuospatial skills, and lack of initiative
  • presence of at least two of the following symptoms:
    • fluctuations in memory, or cognitive disorder
    • visual hallucinations
    • Parkinson’s-like symptoms
  • presence of additional symptoms:
    • difficulty with balance
    • transient loss of consciousness
    • inability to tolerate neuroleptic medications

 

Lewy Body Dementia and Alzheimer’s

Although dementia is present in both LBD and AD, the features of dementia differ between the two. It is unusual to have visual hallucinations in AD, and fluctuations in intellectual functioning are more prominent with LBD. Visuospatial skills and attention are more affected in LBD, whereas language function is more affected in AD. Patients have problems with memory in both LBD and AD, but they are different. In AD, individuals have difficulty consolidating memory (forming new memories), while in LBD, patients have difficulty retrieving memory (accessing previously memorized information). Finally, autonomic dysfunction and sleep behaviour disorders, such as REM sleep behaviour disorder, are more common in Lewy Body Dementia than Alzheimer’s (Alzheimer’s Association, n.d.).

 

Treatment

Unfortunately, there is no cure for LBD at this time. There are, however, some medications that can help ease the symptoms of the disease.

Medications like cholinesterase inhibitors, which are commonly used in Alzheimer’s disease, may help with thinking. They also can be helpful in reducing hallucinations. Medicines that help with the symptoms of PD may also be used in LBD, though they must be used with caution, as they can increase confusion and hallucinations (Mayo Clinic, n.d.).

 

Additional Resources

Lewy Body Dementia Association | www.lbda.org

 

Sources

Alzheimer’s Association (n.d). Dementia with Lewy Bodies. https://www.alz.org/alzheimers-dementia/what-is-dementia/types-of-dementia/dementia-with-lewy-bodies

Alzheimer’s Society UK (2021). Getting a diagnosis of dementia with Lewy bodies (DLB). https://www.alzheimers.org.uk/about-dementia/types-dementia/dementia-with-lewy-bodies-diagnosis

Armstrong, M. J., Alliance, S., Taylor, A., Corsentino, P., & Galvin, J. E. (2019). End-of-life experiences in dementia with Lewy bodies: Qualitative interviews with former caregivers. PLOS ONE. https://doi.org/10.1371/journal.pone.0217039

Heerema, E. (2023). What is Lewy Body Dementia? Very Well Health. https://www.verywellhealth.com/lewy-body-dementia-stages-progression-98735

Mayo Clinic (n.d.). Lewy body dementia. https://www.mayoclinic.org/diseases-conditions/lewy-body-dementia/

National Institutes of Health (n.d.). What Is Lewy Body Dementia? https://www.alzheimers.gov/alzheimers-dementias/lewy-body-dementia

Rogers, K. (2020). Lewy body dementia: The life-changing disease that devastated Robin Williams. CNN. https://www.cnn.com/2020/09/01/health/lewy-body-dementia-explainer-wellness/index.html 


Last updated: February 27, 2024