Lewy body dementia is an umbrella term describing two forms of dementia: dementia with Lewy bodies and Parkinson’s disease dementia.

Dementia is a broad term used to describe a loss of memory, intellect, rationality, social skills, and physical functioning. Not everyone with Parkinson’s will develop dementia.

Lewy body dementia

Lewy bodies are abnormal protein aggregates or clumps that develop inside nerve cells in certain areas of the brain (1). They are a characteristic feature of several neurodegenerative disorders, including Parkinson’s disease, Parkinson’s disease dementia (PDD) and dementia with Lewy bodies (DLB). Everyone with Parkinson’s has clumped Lewy bodies but not everyone will develop PDD or LBD.

There are many types of dementia, but the two types primarily associated with Parkinson’s are Parkinson’s disease dementia (PDD) and dementia with Lewy bodies. The presence of cognitive changes before the emergence of motor symptoms (or within twelve months of showing motor or movement symptoms) suggests DLB rather than PDD or idiopathic Parkinson’s. The Movement Disorder Society has guidelines regarding the differences between the two types to clarify the potential diagnosis (2, 3), but both conditions are caused by the abnormal accumulation of alpha-synuclein protein in the brain, known as Lewy bodies.

Exercise along with other lifestyle changes to stay mentally active, eat well and avoid smoking, excessive alcohol and head injuries may also help reduce dementia risk. Doing regular exercise is one of the best ways to reduce your risk of dementia.

Mild cognitive impairment vs dementia

Mild cognitive impairment (MCI) and dementia are common features in Parkinson’s and characterised by a wide range of cognitive issues but are distinct from those seen in Alzheimer’s. It is estimated that dementia will occur in 30-60% of people affected by Parkinson’s (1). The difference between MCI and dementia in Parkinson’s lies in the severity and impact of cognitive symptoms on daily life:

  • MCI refers to a noticeable decline in cognitive abilities, such as memory and thinking skills, that is greater than expected for a person’s age but does not significantly interfere with daily activities. People with MCI may experience memory lapses, difficulties with problem-solving, or challenges in maintaining focus, but they can still manage their daily tasks independently.
  • Dementia involves more severe cognitive impairment that interferes with daily life and independence. Symptoms include significant memory loss, confusion, disorientation, difficulty with language and communication, impaired judgment, and changes in personality and behaviour. People with dementia often require assistance with daily activities and may not be able to live independently.

Parkinson’s disease dementia

Some individuals with Parkinson’s may later develop cognitive impairment and dementia. In these cases, Lewy bodies are often found in both the brainstem (where they are associated with motor symptoms) and the cerebral cortex (where they are linked to cognitive decline).
Risk factors for developing PDD are:

  • having Parkinson’s for a long time
  • being elderly
  • being diagnosed with Parkinson’s at an older age
  • being non-tremor dominant.

Common features of PDD are:

  • Problems with planning, sequencing and decision making
  • Memory loss associated with free recall of recent events or new learning
  • Memory can improve with cueing
  • Visuo-spatial difficulties
  • Apathy
  • Changes in personality and mood
  • Visual hallucinations may occur.

Long-term use of Parkinson’s medications may also result in confusion and hallucinations.

Frequent monitoring by the treating medical specialist is essential. The decision to introduce medications used in the management of dementia must be made on an individual basis.

Dementia with Lewy bodies

DLB is a progressive brain disorder that shares similarities with both Parkinson’s disease and Alzheimer’s disease. Lewy bodies are a key pathological feature in DLB, affecting multiple brain regions.

Common features of DLB are:

  • Fluctuating cognition early in the progression
  • Recurrent hallucinations early in the progression
  • REM (Rapid Eye Movement) sleep disorder – often acting out dreams
  • Severe sensitivity to medications prescribed for hallucinations
  • Sensitivity to medications prescribed for Parkinson’s.

Symptoms will depend on which area of the brain is affected and disease progression. However likely early symptoms include:

  • apathy, anxiety, depression
  • fainting
  • constipation
  • urinary incontinence
  • excessive sleepiness
  • poor sense of smell
  • parkinsonism (bradykinesia, muscle rigidity, tremor, postural instability)
  • confusion or unresponsiveness that fluctuates
  • visual hallucinations
  • spatial disorientation or trouble with spatial perceptions
  • acting out dreams.

n.b. Levodopa (a drug prescribed for Parkinson’s symptoms) may worsen the cognitive and hallucination symptoms.

Later symptoms include:

  • inability to self-care
  • excessive daytime sleepiness
  • complete dependence.

Key Statistics

  •  More than 100,000 Australians have Lewy body dementia. (1)
  • Integrated outpatient palliative care, in addition to standard care, has improved multiple aspects of care in Parkinson’s disease dementia patients compared to standard care alone.
  • Recent diagnostic criteria have blurred the lines between Parkinson’s disease dementia and dementia with Lewy bodies, particularly in the cognitive domain.

Diagnosis of Parkinson’s-related dementias

A full assessment may include:

  • a medical history from the person
  • an interview with a family member
  • blood tests
  • tests of cognitive abilities
  • brain imaging
  • other medical tests as requested by a doctor or medical specialist.

Imaging techniques like SPECT and PET scans can help identify abnormal protein deposits during a person’s lifetime, aiding in the clinical diagnosis. However, the definitive diagnosis of conditions associated with Lewy bodies, such as Parkinson’s or LBD, is often confirmed through post-mortem examination of brain tissue.

Your care

Currently, there is no cure for disorders associated with Lewy bodies. Treatment focuses on managing symptoms and improving the quality of life for affected individuals. Medications, physical therapy, and support services are often part of the comprehensive care approach for individuals with these conditions.

It’s important to note that research into Lewy bodies and associated neurodegenerative disorders is ongoing, with scientists working to better understand the underlying causes and develop targeted therapies.

Being diagnosed with DLB or PDD can lead to a range of emotions, and there’s a lot to learn. The Dementia Australia information kit helps you learn about your diagnosis, identify goals for the future, and access support and services. Go to www.dementia.org.au or call their National Dementia Helpline 1800 100 500 for support.

Care partners of people with Parkinson’s dementias should prioritise their self-care. Dementia or significant cognitive decline can seriously impact care partner burden. Respite for the carer is essential and forward planning and palliative consultations are recommended. Contact Carers Australia and register on the Carer Gateway for more information on carers’ supports.

Palliative Care Australia can also provide assistance at palliativecare.org.au

References:

  1. Dementia Australia. (2024). Lewy body dementias. Retrieved from
  2. Aarsland D, Kurz MW. The epidemiology of dementia associated with Parkinson’s disease. Brain Pathol. 2010 May;20(3):633-9. doi: 10.1111/j.1750-3639.2009.00369.x. PMID: 20522088; PMCID: PMC8094858. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8094858/
  3. Kiesmann, M., Chanson, J. B., Godet, J., Vogel, T., Schweiger, L., Chayer, S., & Kaltenbach, G. (2013). The Movement Disorders Society criteria for the diagnosis of Parkinson’s disease dementia: their usefulness and limitations in elderly patients. Journal of neurology, 260(10), 2569–2579. https://doi.org/10.1007/s00415-013-7018-8
  4. Yamada, M., Komatsu, J., Nakamura, K., Sakai, K., Samuraki-Yokohama, M., Nakajima, K., & Yoshita, M. (2020). Diagnostic Criteria for Dementia with Lewy Bodies: Updates and Future Directions. Journal of movement disorders, 13(1), 1–10. https://doi.org/10.14802/jmd.19052
  5. Yamada M, Komatsu J, Nakamura K, Sakai K, Samuraki-Yokohama M, Nakajima K, Yoshita M. Diagnostic Criteria for Dementia with Lewy Bodies: Updates and Future Directions. J Mov Disord. 2020 Jan;13(1):1-10. doi: 10.14802/jmd.19052. Epub 2019 Nov 8. PMID: 31694357; PMCID: PMC6987529.
  6. Safarpour D, Willis AW. Clinical Epidemiology, Evaluation, and Management of Dementia in Parkinson Disease. American Journal of Alzheimer’s Disease & Other Dementias®. 2016;31(7):585-594. doi:10.1177/1533317516653823 https://journals.sagepub.com/doi/abs/10.1177/1533317516653823
  7. Phillips, O., Ghosh, D., & Fernandez, H. H. (2023). Parkinson disease dementia management: an update of current evidence and future directions. Current Treatment Options in Neurology, 25(1), 93–119. https://doi.org/10.1007/s11940-023-00749-4
  8. Giannakis, A., Sioka, C., Kloufetou, E., & Konitsiotis, S. (2024). Cognitive impairment in Parkinson’s disease and other parkinsonian syndromes. Journal of Neural Transmission, 31(2), 123–135. https://doi.org/10.1007/s00702-024-02865-0

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