How is Parkinson’s dementia different from Alzheimer’s disease?
The advanced cognitive changes that impact daily living in Alzheimer’s and Parkinson’s disease (PD) are both types of dementia.
Parkinson’s disease dementia (PDD) can occur as Parkinson’s advances, after several years of motor symptoms. Dementia with Lewy Bodies (DLB) is diagnosed when cognitive decline happens first, or when Parkinson’s motor symptoms and cognitive decline occur and progress closely together. Cognitive impairments in PDD, combined with the movement symptoms of the disease, produce a greater impact on social and occupational functioning than Alzheimer’s.
Alzheimer’s, a fatal brain disease, causes declines in memory, thinking and reasoning skills. Physicians (often with the help of specialists such as neurologists, neuropsychologists, geriatricians and geriatric psychiatrists) can diagnose Alzheimer’s. Visit the Alzheimer’s Association to learn the 10 signs Alzheimer’s disease.
Fortunately for people with PD, Parkinson’s disease dementia is less disabling than Alzheimer’s disease. People with Alzheimer’s have language difficulties earlier than people with Parkinson’s, and no new memories are formed. People with PD also have more ability to compensate and adjust based on cues.
Can a person with Parkinson’s disease also have Alzheimer’s disease?
Yes. Alzheimer’s disease and Parkinson’s disease affects different proteins in the brain, making it possible for a person with Parkinson’s to also have Alzheimer’s.
Can a person with Parkinson’s have Parkinson’s disease dementia and Alzheimer’s disease?
While rare, it is possible for a person with PD to be diagnosed with Parkinson’s disease dementia and Alzheimer’s disease. A neurologist who treats Parkinson’s with a neuropsychologist, geriatrician or a geriatric psychiatrist can help diagnose Alzheimer’s disease.
How many people with Parkinson’s develop dementia?
According to recent research, 70 percent of people with Parkinson’s will develop dementia as part of the disease progression.
Is there a test to diagnose PD dementia?
There is no single test for PDD. The diagnosis is made clinically. If you or someone you spend time with notices cognitive changes, it is important to discuss them with your care team. If you don’t have a care team in place, it’s important to find a specialist or physician familiar with dementia or geriatric medicine. Call the Parkinson's Foundation Helpline 1-800-4PD-INFO (473-4636) for a referral.
Do you die from PD dementia?
People with Parkinson’s-related dementia often want to know how the disease can impact their lifespan. While people with Parkinson’s can expect a similar lifespan to the general population, studies show both Parkinson’s disease dementia and Lewy body dementia can shorten lifespan, generally due to medical complications from the disease, rather than the disease itself.
What are PD dementia safety concerns?
Safety issues should be considered and monitored from the time of diagnosis. As PDD progresses, ensure that your loved one is not left alone.
- Evaluate driving privileges before safety is a concern. Your doctor can make a driving evaluation referral.
- Work out legal and financial issues and safeguard finances. People with dementia are at greater risk of falling victim to scams and fraud.
- Minimize prescription risks. Confirm with the doctor the medication names and doses of the person with PD. If the person is in dementia’s early stages and capable, fill up their weekly pill box together and monitor use.
- Medical alert systems can be critical in case your loved one falls or wanders outside of the home. Many types of systems are available, from bracelets and pendants to smart watches with fall detection and one-button connections to 911.
- Evaluate gun safety. If your loved one owns a firearm or has one in the home, consider speaking with their doctor about the subject and taking appropriate safety precautions.
What is the best way to communicate with a person with PDD?
- It is not usually helpful to try to reason or argue with someone experiencing a hallucination or delusion. Stay calm and be patient. If the person is frightened by the hallucination or delusion, try to redirect their attention to something else.
- You may find acknowledging what the person is seeing, even if you do not see it, can reduce stress.
- Speak slowly and at eye level. Communicate in simple sentences.
- Ask one question at a time and wait for an answer.
- Limit distractions. Turn off the TV or radio before asking a person with PDD to do something.
- Consider causes behind disruptive behavior: the person may be hungry, thirsty, tired, in pain, frustrated, lonely or bored.
- If the person is stuck on an idea, try agreeing with them, then changing the subject.
- It’s OK to use humor to diffuse stressful situations but avoid negative humor or sarcasm ― these can be misunderstood.
Page reviewed by Dr. Jori Fleisher, MSCE, Assistant Professor, Department of Neurological Sciences at Rush University Medical Center, a Parkinson’s Foundation Center of Excellence.