Parkinson's Disease Dementia


  • Parkinson’s disease dementia is also known as Lewy body dementia.
  • Lewy bodies are abnormal deposits of protein found in the outer layers of the brain and deep inside the midbrain and brainstem.
  • This is the third most common type of dementia, after Alzheimer’s and vascular dementia.
  • 1.3 million people in the United States have Parkinson’s disease dementia.
  • Motor and dementia symptoms usually occur within one year of each other.


  • Progressive decline in memory and ability to think
  • Difficulty interpreting visual information
  • Fluctuating alertness and symptoms from moment to moment and day to day
  • Delusions and vivid, visual hallucinations which are generally not frightening
  • Problems with movement resembling Parkinson’s disease such as shuffling gait, balance difficulties, tremor, muscle stiffness, and slow movement
  • Frequent falls
  • Sleep disorder with vivid dreams and excessive movement while sleeping
  • Daytime drowsiness


  • No known cause or risk factors
  • Age at diagnosis usually 50-85 years old
  • Worsening of symptoms may be seen after anesthesia


  • It can be difficult to diagnose because Parkinson’s disease dementia symptoms are similar to Alzheimer’s and other dementias.


  • Memory medication may be used to help brain cells communicate with each other.
  • Read the website document Memory Medications for more information.
  • Patients with Parkinson’s disease dementia may have increased risk of side effects from medications.