How Parkinson’s Disease and Dementia Are Related

Parkinson's disease and dementia

Parkinson’s affects about 1 million Americans

It’s estimated that 1 million Americans have Parkinson’s disease. It’s a neurological disorder typically seen in older adults — affecting about 2% of people over age 65.

About 50 – 80% of people with Parkinson’s develop Parkinson’s disease dementia, but the dementia symptoms usually take 10 – 15 years to appear.

We explain what Parkinson’s disease is, how Parkinson’s disease dementia is different from Lewy body, other causes of dementia-like symptoms, and how to find a helpful support group.



What is Parkinson’s disease?

Parkinson’s disease is a progressive disorder of the nervous system that affects movement. It develops gradually, usually starting with barely noticeable hand tremors.

Typical Parkinson’s symptoms include:

  • Tremors
  • Stiffness
  • Slow movement
  • Face showing little or no expression
  • Soft or slurred speech
  • Arms that don’t swing when walking


What is Parkinson’s disease dementia?

Parkinson’s disease dementia has symptoms similar to those found in Lewy body dementia so it can sometimes be tough to diagnose.

But according to the Alzheimer’s Association, someone has Parkinson’s disease dementia if they were originally diagnosed with Parkinson’s based on movement symptoms and their dementia symptoms didn’t appear until a year or more later.


Parkinson’s disease dementia vs Lewy body dementia

Lewy body dementia is typically when:

  • Dementia symptoms appear within 1 year after movement symptoms
  • Both dementia symptoms and movement symptoms are present at the time of diagnosis
  • Movement symptoms develop within a year of a Lewy body dementia diagnosis

Many experts now believe that Parkinson’s disease dementia and dementia with Lewy bodies are caused by the same problems with brain processing of a specific protein (alpha-synuclein). But they still recommend diagnosing dementia with Lewy bodies and Parkinson’s dementia as separate diseases.


Symptoms of Parkinson’s disease dementia

Symptoms of cognitive impairment include:

  • Loss of decision-making ability
  • Inflexibility in adapting to changes
  • Disorientation in familiar surroundings
  • Problems learning new material
  • Difficulty concentrating
  • Loss of short- and long-term memory
  • Difficulty putting a sequence of events in correct order
  • Problems using and understanding complex language


Other causes of dementia-like symptoms in Parkinson’s disease

Dementia isn’t the only reason for someone with Parkinson’s to have dementia-like symptoms. They could also be caused by mental disorders, treatable conditions, or medication side effects.

Common mental disorders in Parkinson’s disease could also cause dementia-like symptoms, including:

  • Depression –  sadness, tearfulness, fatigue, withdrawal, loss of interest in activities once enjoyed, sleeping too much or too little, weight gain or loss
  • Anxiety – excessive worry or fear that disrupts everyday activities or relationships, restlessness, extreme fatigue, muscle tension, sleeping problems
  • Psychosis – inability to think realistically, hallucinations, delusions (believing in things that are untrue), paranoia (suspicious and feeling controlled by others), and problems with thinking clearly



Support groups for Parkinson’s, with or without dementia

Parkinson’s disease is tough to live with, both for the person affected and their family. Support groups are filled with people who are going through very similar experiences. They’re a great place to safely vent frustrations, get new ideas for how to cope or solve problems, and learn about helpful resources.

Check with these organizations to find a support group in your area:


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By DailyCaring Editorial Team
Sources: eMedicineHealth, Alzheimer’s Association
Image: Wall Street Daily


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