Parkinson’s Disease with Dementia: Causes, Symptoms, Treatments & Caregiving

Last Updated: March 17, 2020


Roughly one million people in the U.S. have Parkinson’s disease, and more than half of them will develop dementia, referred to as “Parkinson’s Disease with Dementia” or PDD . Changes in the brains of people with Parkinson’s typically affect movement and motor skills first. Somewhere between 50% and 80% of individuals will have their thinking and reasoning ability so impacted that the diagnosis changes to Parkinson’s Disease with Dementia (PDD).

PDD occurs because of damage to the cells that create dopamine, a chemical in the brain that has several functions including helping us move and think. Symptoms come on very slowly, usually beginning with shakiness, slowed movement, stooped posture, and difficulty walking. Eventually, anxiety and dementia often develop. The average amount of time between diagnosis of Parkinson’s and the onset of dementia is about 10 years.


Causes of Parkinson’s Disease with Dementia (PDD)

Experts do not know what causes Parkinson’s disease. (The term for this is “idiopathic.”) Genetic and environmental factors may play a role. Someone who has family members with the disease is slightly more likely to develop Parkinson’s. It has also been linked with exposure to pesticides and to head injuries. There is some evidence that having never smoked or drank caffeinated beverages like coffee and tea actually increases a person’s chance of developing Parkinson’s.

Between 50 and 80 percent of people with Parkinson’s Disease will develop dementia because of the spreading deterioration of brain cells over time. Motor skills and movement are affected first – causing shaking, rigidity, and slowness – but after enough time the brain’s structure changes to the point where problem solving and memory become affected.

Risk factors for someone who has Parkinson’s to develop PDD are:
– Old age
– Gender (men with Parkinson’s are statistically more likely to develop dementia than women)
– Long duration of Parkinson’s (advanced stages)
– Family history of dementia
– Daytime drowsiness
– Hallucinations before other dementia symptoms
– Movement problems that are beyond typical for Parkinson’s (like an inability to walk)


How PDD Compares to Dementia with Lewy Bodies

A diagnosis of Parkinson’s disease with dementia is only made when those symptoms listed above develop at least one year after diagnosis. If dementia symptoms arrive around the same time as other symptoms of Parkinson’s (mainly movement), then it is probably Dementia with Lewy Bodies. Lewy bodies are protein tangles found in the brains of people with dementia. The same parts of the brain are affected in both PDD and Lewy body dementia.


How PDD Compares to Alzheimer’s Disease

Alzheimer’s disease and Parkinson’s disease with dementia share symptoms including memory loss, but there are differences as well. Parkinson’s can actually be more difficult to live with than Alzheimer’s because of the physical symptoms, like difficulty moving, that develop before dementia. Alzheimer’s disease does eventually affect someone’s ability to move, but not as soon or as totally as Parkinson’s. Very generally, Alzheimer’s disease most directly impacts communication and memory, while PDD robs the brain of its problem-solving skills and thinking speed. PDD also has been shown to more strongly affect mood, or in other words is more likely to cause anxiety and depression.


Symptoms and Mortality of Parkinson’s Disease with Dementia

Parkinson’s disease (PD) turns into Parkinson’s disease with dementia (PDD) at least one year after the initial diagnosis, well after those PD symptoms above become apparent. As PD becomes PDD, the following symptoms start to appear:
– Anxiety, depression, and irritability
– Delusions (a strong belief in things that are obviously untrue)
– Paranoia
– Difficulty sleeping despite fatigue
– Slurred speech
– Inability to process visual information (difficulty seeing)
– Hallucinations
– Memory loss

While people with Parkinson’s have only slightly higher mortality rates than people without the disease, mortality rates significantly increase for people with PDD. In other words, someone with PDD is more likely to die sooner than someone who has Parkinson’s without dementia. The disease is not fatal—you cannot die from Parkinson’s—but mortality rates increase because falls and accidents become more likely. Add dementia and it becomes dangerous, making caregiving, or finding the right assisted living or memory care home (see below), more important.


Treatment and Medications for Parkinson’s Disease with Dementia

There is no way to reverse the progression of Parkinson’s disease with dementia, but it is still possible to slow and manage symptoms so that your loved one with this disease can live as rich and full a life as possible. Speaking with a doctor who specializes in these cases (a neurologist or specialist in movement disorders) is obviously a good idea. Counseling and certain therapies can help; physical, occupational, and speech therapy have benefited people with dementia. It may be a good idea to tackle some symptoms individually. Therapy or antidepressants, for instance, can help with depression and anxiety.

There is not a “gold standard” for medications that help people with Parkinson’s disease, according to studies. This means that it’s important to have a doctor tailor medications to specific individuals. Drugs for restoring dopamine activity have been shown to help with physical symptoms like tremors, but no medication is available to specifically target the symptoms of Parkinson’s disease dementia.

That said, cholinesterase inhibitors are one of the few drugs available that have been shown to help thinking and memory for people with Alzheimer’s disease, and studies have shown that people with PDD see benefits as well. Cholinesterase inhibitors increase communication between brain cells, and in particular can help control hallucinations and improve sleep.

Antidepressants and antipsychotics may also help with symptoms including mood and hallucinations, but the side effects of these drugs can be powerful. Only give your loved one medication after consulting with a doctor.

Makers of supplements like caprylic acid say they can help with symptoms of dementia, but there have not been enough studies to determine whether they actually work. The internet is filled with convincing videos about the positive effect of CBD on Parkinson’s symptoms. More on CBD’s impact, legality and availability.


Caregiving at Home

Caregiving obviously becomes more difficult when a person with Parkinson’s develops dementia. Fortunately, there are simple communication techniques and strategies to help keep your loved one as safe and functional as possible.

Caregivers for loved ones with Parkinson’s should consider the following:
– Look into aids for people with Parkinson’s. There are special pens, weighted utensils, key turners, no-spill cups, canes, and more that will help maintain some independence as symptoms worsen.
– Any physical exercise, even something as simple as standing and sitting regularly, is a good idea to promote brain health.
– Serve softer food, like blended nutritious smoothies, as swallowing becomes difficult. Avoid food with crumbs that might get caught in the throat.
– Inspect the home for safety issues, and install grab bars and handrails in the bathroom and wherever else they might be necessary. People with Parkinson’s are prone to falls, especially after dementia sets in.

The disorientation that comes with dementia will change a person with Parkinson’s. They may not be able to be left alone, and may become moody, impulsive, and aggravated. Try these strategies for specifically addressing dementia symptoms:
– Establish a daily routine. When meals, exercise, and activities happen at roughly the same time each day, your loved one will be less prone to becoming upset.
– Simplify living areas so that there are less distractions and, later in the day, shadows.
– Keep the home brightly lit.
– Add signs around the house (like “Bathroom”) so forgetfulness matters less.
– Remain calm and empathetic. Remember it’s the disease that causes your loved one’s erratic behavior, not any decision on their part.

And remember to take care of yourself. Caregiver stress is a significant problem because the person being cared for can pick up on your mood through even subtle cues like facial expressions. Be sure to get enough sleep and practice principles of self-care so that you’re at your best when dealing with dementia-related behavior.

More on communication strategies for Parkinson’s with dementia. For tips on coping with emotional and behavioral issues, click here.


Residential Care Options for PDD: Assisted Living, Memory Care & Nursing Homes

People with advancing Parkinson’s disease will find it difficult and then impossible to perform basic tasks like dressing or preparing one’s own food. This makes caregiving essential, but it becomes much harder when dementia develops, and you may need to find a long-term care home with staff to serve your loved one’s needs. There are not long-term-care communities exclusively for people with Parkinson’s disease, but assisted living, memory care, and nursing homes are options to consider when keeping your loved one in the house is no longer viable. Any of these will provide meals, assistance with activities of daily living like bathing and dressing, supervision, and emergency medical care. Where they differ is in the amount of care provided and cost.


Assisted Living

Assisted living without memory care may be an option for a while, if your loved one remains able to make decisions and stay safe but requires help with activities of daily living like dressing and eating. These homes provide 24-hour help with activities of daily living (ADLs) like dressing and bathing, but also try to encourage residents to maintain some independence. New residents are assessed to determine needs and whether or not the home is appropriate, but it’s important to remember that when dementia advances it will be necessary to find a more comprehensive option like memory care, and this means a disruptive move might become necessary. Furthermore, assisted living residences might choose to evict a resident when they can no longer provide for their care needs which means a move from assisted living to memory care may come unexpectedly.


  How Prices Compare: Memory care is more expensive than assisted living, because of heightened training and care, but less expensive than a nursing home. The average cost of memory care in the U.S. is about $5,000 per month, compared to about $4,000 for assisted living and $7,000 for a nursing home.


Memory Care

With the onset of dementia symptoms, memory care becomes the better option because staff is specifically trained to assist and communicate with people who show symptoms of dementia. Special design features and security measures also distinguish memory care from other living options. Basically, this is the best choice for people with dementia symptoms who cannot stay safe without full-time care and supervision.


Nursing Homes

Nursing homes (or “skilled nursing facilities”) offer room and board and personal care like assisted living and memory care communities, but also provide 24-hour medical care. Assisted living and memory care are typically more like supervised apartment-style living, while nursing homes could usually be compared to an indefinite stay in the hospital. If your loved one’s dementia is so far advanced that choking or falling are constant dangers, a nursing home is probably the best option. A nursing home would also be necessary if there are other serious health issues beyond Parkinson’s. For people in the very late stages of the disease, nursing homes are most likely to offer palliative and end-of-life care.


  Compare memory care and nursing homes or receive free assistance finding residential care for persons with Parkinson’s related dementia.