Parkinson’s disease is the second most common neurodegenerative disease worldwide, currently affecting an estimated 9.4 million people globally and approximately one million in the United States. While best known for causing tremors, stiffness, and difficulty with movement, Parkinson’s also affects cognition. As the disease progresses, many people develop what’s known as Parkinson’s disease dementia—a complication that significantly impacts both the person with Parkinson’s and their family.
Understanding Parkinson’s disease dementia helps families prepare for changes ahead and make informed decisions about care. This guide covers what causes Parkinson’s disease dementia, how to recognize symptoms, current treatment options, and how professional home care can help your loved one maintain quality of life.
How Common Is Parkinson’s Disease Dementia?
Cognitive changes are among the most common non-motor symptoms of Parkinson’s disease. Research shows that 25% to 30% of people already have mild cognitive impairment at the time of their Parkinson’s diagnosis. As the disease progresses, 50% to 70% of patients experience cognitive problems, and dementia affects nearly half of people within 10 years of diagnosis.
A 2024 meta-analysis published in Movement Disorders found that the annual risk of developing dementia in people with Parkinson’s is approximately 4.5%, and people with Parkinson’s are more than three times as likely to develop dementia compared to those without the disease. Approximately 1.7 million people globally are affected by Parkinson’s disease dementia, though this number is expected to rise as the population ages.
What Causes Parkinson’s Disease Dementia?
Scientists have identified several brain changes associated with both Parkinson’s disease and its cognitive symptoms. The primary culprit is the accumulation of abnormal deposits of the protein alpha-synuclein, which form clumps known as Lewy bodies—named after the German neurologist Friedrich Lewy, who first described them in 1912.
Lewy bodies disrupt normal brain function by interfering with chemical messengers called neurotransmitters. In Parkinson’s disease, dopamine-producing neurons are damaged, causing movement problems. As Lewy bodies spread to other brain regions, they also affect acetylcholine, a neurotransmitter critical for memory and thinking. Research shows that people with Parkinson’s disease dementia actually have greater cholinergic deficits than people with Alzheimer’s disease who have similar levels of cognitive impairment.
A 2025 study from the Parkinson’s Foundation found that brain inflammation and the buildup of another protein called tau are early drivers of cognitive decline in Parkinson’s. Researchers discovered that people at higher risk for dementia showed more brain inflammation and performed worse on cognitive tests—a finding that could eventually help identify those at greater risk before symptoms become severe.
Many people with Parkinson’s disease dementia also have plaques and tangles in the brain—the same protein deposits found in Alzheimer’s disease. This overlap helps explain why some people develop cognitive problems earlier or more severely than others.
Parkinson’s Disease Dementia vs. Lewy Body Dementia
You may have heard the term Lewy body dementia and wondered how it relates to Parkinson’s disease dementia. The distinction can be confusing because both conditions involve Lewy bodies in the brain and share many symptoms.
Lewy body dementia is actually an umbrella term that encompasses two related conditions:
- Parkinson’s disease dementia (PDD) — Cognitive impairment that develops in someone with established Parkinson’s disease, typically after years of living with motor symptoms
- Dementia with Lewy bodies (DLB) — Cognitive symptoms appear first or within one year of motor symptoms
The key difference is timing. If someone has had Parkinson’s disease for years and then develops dementia, it’s classified as Parkinson’s disease dementia. If cognitive problems appear early—before or around the same time as movement symptoms—the diagnosis is dementia with Lewy bodies.
Despite this clinical distinction, a 2024 study published in Movement Disorders Clinical Practice concluded that PDD and DLB are essentially expressions of the same underlying disease at different stages. Both show widespread Lewy body pathology and similar patterns of brain changes at autopsy. For families, this means many of the same care strategies and treatments apply to both conditions.
Symptoms of Parkinson’s Disease Dementia
People with Parkinson’s disease typically experience motor symptoms first—the cognitive component often appears later as the disease progresses. Understanding both types of symptoms helps families recognize changes that may indicate the development of dementia.
Motor Symptoms of Parkinson’s Disease
- Tremors in the hands, arms, legs, and jaw
- Rigidity and stiffness in the limbs and trunk
- Slowness of movement (bradykinesia)
- Loss of balance and coordination
- Difficulty speaking or soft speech
- Facial masking (reduced facial expressions)
- Difficulty swallowing
- Stooped posture and shuffling gait
Cognitive and Psychiatric Symptoms
When cognitive symptoms become severe enough to interfere with daily activities, it’s classified as Parkinson’s disease dementia. Common symptoms include:
- Problems with attention and concentration
- Difficulty with executive function (planning, organizing, problem-solving)
- Slowed thinking and processing speed
- Visuospatial difficulties (judging distances, navigating spaces)
- Memory problems, particularly with recall
- Confusion and disorientation
- Personality and mood changes
- Depression and anxiety
- Apathy and loss of motivation
- Visual hallucinations (seeing things that aren’t there)
- Delusions (false beliefs)
- Sleep disturbances, including REM sleep behavior disorder
Visual hallucinations and fluctuating attention are particularly characteristic of Parkinson’s disease dementia. Some people may have clear, lucid periods followed by episodes of confusion—a pattern called cognitive fluctuations. These symptoms can be distressing for both the person experiencing them and family members providing care.
Risk Factors for Developing Parkinson’s Disease Dementia
Not everyone with Parkinson’s disease will develop dementia. Research has identified several factors that increase the risk:
- Older age and older age at Parkinson’s diagnosis
- Longer disease duration — dementia risk increases as Parkinson’s progresses
- More severe motor symptoms, particularly postural instability and gait problems
- Mild cognitive impairment (MCI) at or soon after diagnosis
- REM sleep behavior disorder
- Visual hallucinations without dementia
- Depression
- Certain genetic factors, including GBA gene mutations
A 2025 study also linked long-term exposure to air pollution, particularly fine particulate matter (PM2.5), to higher rates of Lewy body dementia—highlighting the importance of environmental factors in brain health.
Current Treatments for Parkinson’s Disease Dementia
While there is no cure for Parkinson’s disease dementia, several treatments can help manage symptoms and improve quality of life. Treatment typically involves a combination of medications for motor, cognitive, and psychiatric symptoms.
Medications for Cognitive Symptoms
→ Rivastigmine (Exelon) — The only FDA-approved medication specifically for Parkinson’s disease dementia. This cholinesterase inhibitor increases acetylcholine levels in the brain. Studies show it provides moderate improvements in cognition, attention, executive function, and behavioral symptoms. Available as oral capsules, liquid, or a transdermal patch.
→ Donepezil and galantamine — Other cholinesterase inhibitors are sometimes used off-label, though the evidence is less robust than for rivastigmine.
Medications for Hallucinations and Delusions
→ Pimavanserin (Nuplazid) — The only FDA-approved treatment for Parkinson’s disease psychosis (hallucinations and delusions). In 2024, the FDA updated the label to clarify that pimavanserin can be used for patients with Parkinson’s disease psychosis, whether or not they also have dementia. Unlike traditional antipsychotics, pimavanserin does not worsen motor symptoms or cognitive function.
→ Quetiapine and clozapine — Atypical antipsychotics are sometimes used when other treatments aren’t effective. Clozapine requires regular blood monitoring.
▶ Important: Most antipsychotic medications can worsen Parkinson’s motor symptoms and carry serious risks for people with dementia. Any medication changes should be made only under close supervision by a neurologist or movement disorder specialist.
Treatments for Motor Symptoms
Levodopa and other dopaminergic medications remain the gold standard for managing Parkinson’s motor symptoms. In 2024-2025, new delivery methods were approved, including Crexont (extended-release oral capsules) and the Vyalev pump (continuous subcutaneous infusion) to provide more consistent symptom control.
For advanced Parkinson’s disease, the FDA approved adaptive deep brain stimulation (aDBS) in February 2025—a groundbreaking technology that continuously monitors brain activity and delivers precisely calibrated electrical pulses to keep symptoms at bay.
Research and Emerging Treatments
Significant research is underway to find treatments that can slow or stop the progression of Parkinson’s disease and its cognitive symptoms:
- Prasinezumab entered Phase III clinical trials in 2025—this antibody targets alpha-synuclein protein buildup and could potentially slow disease progression
- Ambroxol, a common cough medicine in Europe, showed promise in a 2025 study for stabilizing symptoms in Parkinson’s disease dementia patients over 12 months
- Stem cell therapies showed safety and increased dopamine production in early studies
- Gene therapies are being developed that could provide continuous neuroprotection
The Importance of Non-Pharmacological Approaches
Medications are just one piece of managing Parkinson’s disease dementia. Research consistently shows that non-pharmacological interventions play a vital role in maintaining function and quality of life:
✓ Physical exercise — Aerobic exercise has been shown to improve executive function and may help protect brain health
✓ Cognitive stimulation — Engaging in mentally stimulating activities can help maintain cognitive abilities
✓ Physical therapy — Helps maintain mobility, balance, and independence
✓ Occupational therapy — Provides strategies to adapt daily activities and maintain independence
✓ Speech therapy — Addresses swallowing difficulties and communication challenges
✓ Consistent daily routines — Structure reduces confusion and anxiety
✓ Social engagement — Maintaining connections with family and friends supports emotional well-being
Supporting Family Caregivers
Caring for someone with Parkinson’s disease dementia is demanding. A 2024 scoping review of caregiver burden found that the unique combination of motor symptoms, cognitive impairment, and behavioral changes in Parkinson’s disease creates significant challenges for family caregivers—affecting their physical health, emotional well-being, social connections, and finances.
Research has identified factors that increase caregiver burden:
- Severity of cognitive impairment and dementia
- Psychosis, hallucinations, and behavioral changes
- Sleep disturbances in the person with Parkinson’s
- Falls and safety concerns
- Increasing hours of daily caregiving
- Caregiver’s own health problems and lack of support
The study found that caregivers of male patients and those caring for someone with dementia plus psychosis experience particularly high strain. Interventions that have shown promise include cognitive-behavioral therapy for caregivers, mindfulness training, respite care, and combined patient-caregiver programs like cognitive stimulation therapy.
How Professional Home Care Can Help
Living with Parkinson’s disease dementia is challenging, but with the right support, many people can remain safely in the comfort of their own home. Professional non-medical home care provides practical assistance that addresses the unique needs of people with Parkinson’s disease dementia while giving family caregivers essential respite.
Safety and mobility support: Parkinson’s increases fall risk, and cognitive changes can compound safety concerns. Professional caregivers provide standby assistance for walking, transfers, and navigating the home. They can help implement safety modifications and provide supervision during activities that present risk.
Medication reminders: People with Parkinson’s disease often take multiple medications on complex schedules. Cognitive changes make it difficult to remember doses and timing. Caregivers provide reminders and help ensure medications are taken correctly—critical for maintaining symptom control.
Personal care assistance: As motor and cognitive symptoms progress, daily activities like bathing, dressing, grooming, and toileting become increasingly difficult. Professional caregivers provide dignified assistance while encouraging the person to do as much as they can independently.
Meal preparation and nutrition: Swallowing difficulties, reduced appetite, and difficulty with meal preparation are common. Caregivers prepare nutritious meals, assist with eating when needed, and ensure adequate hydration—all of which are important for overall health and medication effectiveness.
Transportation: Most people with Parkinson’s disease eventually stop driving. Professional caregivers provide transportation to medical appointments, therapy sessions, and social activities—helping maintain connections that support mental and emotional health.
Cognitive engagement: Mental stimulation helps maintain cognitive function. Caregivers engage their clients in conversation, reminiscence, puzzles, games, and activities they enjoy. This one-on-one attention provides meaningful interaction that benefits both cognition and mood.
Respite for family caregivers: Perhaps most importantly, professional home care gives family caregivers time to rest, attend to their own health, maintain employment, and prevent the burnout that affects so many Parkinson’s caregivers. Even a few hours of regular respite can significantly reduce caregiver stress.
We hope this guide to Parkinson’s disease dementia has been helpful for your family. If you have questions about caring for a loved one with Parkinson’s disease dementia, contact All Heart Home Care at (619) 736-4677. As a veteran-owned, nurse-led home care agency serving San Diego County since 2014, we understand the complex needs of families navigating neurodegenerative diseases. We offer complimentary in-home consultations and would welcome the opportunity to discuss how our caregivers can support your family.
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Parkinson’s disease dementia is a complex condition that requires individualized care from qualified healthcare providers. Always consult your loved one’s neurologist or movement disorder specialist before making changes to medications or treatment plans. All Heart Home Care provides non-medical supportive care and does not provide medical services.
References
- Gibson, J.S., et al. (2024). Risk of Dementia in Parkinson’s Disease: A Systematic Review and Meta-Analysis. Movement Disorders. doi.org/10.1002/mds.29918
- Parkinson’s Foundation. (2025). Statistics. parkinson.org/understanding-parkinsons/statistics
- Parkinson’s Foundation. (2025). Top Parkinson’s Science News Articles of 2025. parkinson.org/blog/science-news/2025-top-science-news
- Lewy Body Dementia Association. (2024). New Research Supports Nuplazid (Pimavanserin) Use in Parkinson’s Disease Dementia. lbda.org
- American Parkinson’s Disease Association. (2024). Lewy Bodies, Dementia, and Parkinson’s – What Does it all Mean? apdaparkinson.org
- National Institute of Neurological Disorders and Stroke. Parkinson’s Disease: Challenges, Progress, and Promise. ninds.nih.gov
- Aamodt, W.W., et al. (2024). Caregiver Burden in Parkinson’s Disease: A Scoping Review of the Literature from 2017-2022. Journal of Geriatric Psychiatry and Neurology. doi.org/10.1177/08919887231195219



