“Lewy body dementias” is an umbrella term describing two forms of dementia: dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PD-D).
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 Dementias
Cognitive impairment 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 (1). It is estimated to occur in 30-60% of people affected by Parkinson’s.
Doing regular exercise is one of the best ways to reduce your risk of dementia. 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 (2).
Parkinson’s-related Dementias
There are many types of dementia, but the two types primarily associated with Parkinson’s are Parkinson’s disease Dementia (PD-D) and dementia Lewy Body. The presence of cognitive changes before the emergence of motor symptoms (or within twelve months of showing motor or movement symptoms) suggests LBD rather than PD-D or idiopathic Parkinson’s.
Lewy bodies are abnormal protein aggregates that develop inside nerve cells in certain areas of the brain. They are a characteristic feature of several neurodegenerative disorders, including Parkinson’s disease and Lewy body dementia. Everyone with Parkinson’s has clumped Lewy bodies but not everyone will develop PD-D or LBD.
The Movement Disorder Society has guidelines regarding the differences between the two types to clarify the potential diagnosis.
Parkinson’s Disease Dementia (PD-D)
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 PD-D 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 PD-D 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.
Lewy Body Dementia (LBD)
LBD 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 LBD, affecting multiple brain regions.
Common features of LBD 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.
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 LBD or PD-D 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.
References:
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.
https://journals.sagepub.com/doi/abs/10.1177/1533317516653823
