Parkinson’s Disease Dementia: Timing, Behavioral Changes, and More
Some, but not all, people with Parkinson’s disease develop dementia. When it occurs, it tends to develop well after the movement symptoms appear.
This article will explain the link between Parkinson’s disease and dementia. It will also explore the treatment and diagnostic methods.
Defining Parkinson’s disease dementia
Early stage Parkinson’s disease causes movement symptoms, such as mild tremors. Over time, changes in the brain also affect mental function.
According to the Parkinson’s Foundation, about 50% of people with Parkinson’s disease will eventually experience mild cognitive impairment (MCI). This includes memory, thinking, reasoning, and language impairments that do not significantly impact the ability to function.
MCI may progress to dementia when severe cognitive symptoms impair your ability to function. A significant loss of brain cells and communication between them causes dementia. Several conditions can result in dementia, with Alzheimer’s disease being the most well known.
Up to 70% of people with Parkinson’s disease develop dementia.
Dementia vs. hallucinations and psychosis
Parkinson’s disease dementia is not related to the mental side effects, such as hallucinations and psychosis, that can result from some Parkinson’s disease medications. Dementia is a progressive neurological condition. In contrast, medication-related side effects resolve after stopping or reducing the medication.
Symptoms of Parkinson’s disease dementia
Parkinson’s disease dementia can cause a wide variety of symptoms, including behavioral and cognitive changes.
Behavioral changes may include:
Thinking, language, and problem-solving issues may include:
- difficulty concentrating and learning
- difficulty understanding complex concepts
Other possible symptoms can include trouble sleeping and changes in appetite.
Learn about other symptoms here.
Parkinson’s disease stages and dementia
Parkinson’s disease progresses through 5 stages:
- Stage 1: This is when mild movement symptoms appear.
- Stage 2: This is when movement symptoms become severe.
- Stage 3: This is when loss of balance may start and lead to mild-to-moderate disability.
- Stage 4: This is when symptoms fully develop and cause severe functional issues.
- Stage 5: In this stage, it is impossible to walk or stand.
Dementia symptoms develop after the movement symptoms develop. However, the time between one to the other varies considerably between people and studies.
A study of 141 people with Parkinson’s disease finds that about 50% of those with normal cognition at the time of diagnosis developed MCI within 6 years. Every person with a new MCI diagnosis developed full dementia within 5 years.
Unlike Parkinson’s disease itself, the stages of Parkinson’s disease dementia are unclear.
Causes of Parkinson’s disease dementia
In early Parkinson’s disease, specific nerve cells, which help control purposeful movements, change. This alteration causes a loss of dopamine, a brain chemical that regulates movement. Loss of dopamine is the source of the tremors, muscle stiffness, and other movement symptoms of Parkinson’s disease.
The disease process also involves the brain protein alpha-synuclein. The protein aggregates, forming clumpy deposits and inflammation.
These clumpy deposits are Lewy bodies. They affect the standard functioning of the brain and cause cognitive symptoms. Alpha-synuclein also plays a role in Lewy body dementia, separately from Parkinson’s disease.
Risk factors of Parkinson’s disease dementia include:
- being 65 years or older
- having excessive daytime sleepiness
- having existing mild cognitive impairment
- having severe motor symptoms, such as rigidity and gait disturbance
- experiencing hallucinations without other dementia symptoms
Parkinson’s dementia vs. Alzheimer’s dementia
With Alzheimer’s disease, brain damage is primarily due to changes in two proteins — amyloid and tau. These changes allow the proteins to form unusual structures that appear to start in the part of the brain responsible for forming memories.
As such, people with Alzheimer’s dementia have significant problems forming new memories. They also experience cognitive deficits in thinking, reasoning, and communication.
With Parkinson’s disease, brain damage is primarily due to Lewy bodies. However, amyloid and tau may also play a role. As with Alzheimer’s disease dementia, Parkinson’s disease dementia also involves deficits in memory, thinking, reasoning, and language.
Parkinson’s disease dementia tends to be less severe than Alzheimer’s disease. Language deficits may develop earlier in people with Alzheimer’s disease than in Parkinson’s disease. The type of memory loss is also different.
A small study shows that an impaired ability to recall and hold information — temporary memory binding — specifically occurs in people with Alzheimer’s disease but not Parkinson’s disease dementia.
Learn about types of dementia.
Diagnosing Parkinson’s disease dementia
Diagnosing Parkinson’s disease dementia can be tricky, as the condition can mimic other types of dementia. It is also possible to have more than one cause of dementia.
Your doctor will make every effort to reach the right conclusion. They will perform tests to evaluate your mental status and rule out other possible factors and causes of your symptoms.
They will also monitor your clinical signs and the progression of your condition. The criteria for dementia include:
- cognitive or behavioral symptoms that interfere with daily activities
- symptoms that are more pronounced compared with previous levels of function
- symptoms that are not due to delirium or a psychiatric disorder
Your doctor will also evaluate whether your symptoms could be due to a medication side effect.
Treatment of Parkinson’s disease dementia
Current treatments for Parkinson’s disease dementia cannot cure the condition or stop it from progressing. However, they can help manage symptoms.
Doctors may prescribe a combination of medications, cognitive mediation, and behavior management.
Medications may include:
- cholinesterase inhibitors to treat cognitive impairment
- selective serotonin reuptake inhibitors (SSRIs) to reduce the symptoms of depression
- clonazepam (Klonopin) and melatonin to help manage sleep disturbances
This is when caregivers provide a simplified environment to reduce confusion and perception problems.
- organizing living spaces
- providing a structured, daily routine
- using low lighting at night
- avoiding complete darkness
- maintaining consistent timing of light and dark
This treatment focuses on improving cognitive skills. Specifically, it aims to improve:
- memory or thinking symptoms
- daily function
A trained mental health professional will administer this treatment with the support of caregivers and family members.
Parkinson’s disease does not typically cause death.
However, movement and cognitive symptoms, including dementia, can seriously affect a person’s ability to independently perform everyday activities.
If you have MCI or dementia, you can take some steps to reduce the impact of the condition on your life:
- Eat well: A healthy, balanced diet can promote your well-being and help prevent malnutrition.
- Stay active: Fill your time with active yet simple tasks, either alone or with people who set you at ease. Activities may include hobbies, games, or exercise.
- Ask for help: Reduce your task time by asking friends and family members for help.
If you are a caregiver of someone with dementia, try to adopt these practices:
- Enroll in caregiving training courses.
- Keep the person calm at all times.
- Provide a healthy, balanced diet.
- Help with everyday tasks, such as shopping.
- Ensure that the person gets lots of sunlight and physical activity during the day.
- Prioritize self-care, too.
The National Institute on Aging (NIA) also provides information and resources to help you make care decisions.
Heidi Moawad, M.D., reviewed the following questions.
Does dementia always occur with Parkinson’s disease?
Not everyone with Parkinson’s disease will develop dementia. However, as many as 1 in 10 people with Parkinson’s disease get dementia every year.
What are the signs that Parkinson’s disease is getting worse?
Parkinson’s disease is a progressive condition, meaning it will typically worsen with time. Signs of progression include difficulty walking and talking, trouble sleeping, and depression.
Parkinson’s disease dementia causes serious cognitive disorders in people with Parkinson’s disease. Common symptoms include disorientation, confusion, and difficulty concentrating.
Doctors often diagnose the condition by performing some tests. They will also monitor the clinical signs and the progression of the condition.
Treatment methods include medications, behavior management, and cognitive mediation.
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