“My husband has Parkinson’s and dementia. The tip I would give is to get a durable power of attorney (DPOA) early for the spouse (or whomever they wish). I wanted to get the DPOA while my husband still knew what decisions he was making.”
—MARY T., PWP
Parkinson’s disease dementia (PDD) is common in people with PD, though it’s important to note that not everyone with PD will experience dementia. It is estimated that anywhere from 50 to 80 percent of people with Parkinson’s have PDD.76 Generally, if a person with Parkinson’s develops dementia, they do so after having lived with the disease for many years or even decades. My mom had had PD for about 22 years when she first showed signs of dementia.
In addition to having lived with the disease for many years, Parkinson’s patients who experience hallucinations, mild cognitive impairment (MCI), excessive daytime sleepiness, and/or more severe motor control problems have the greatest risk of developing dementia.
Like other types of dementia that destroy brain cells, PDD gets worse over time and the speed of progression can vary.
There are two types of dementia associated with Parkinson’s: PDD and dementia with Lewy bodies (DLB). These conditions are very similar in how they appear, both in person and when the affected brains are looked at under a microscope. The difference is in the timing.
PDD is diagnosed when a person with PD has had motor symptoms for a year or more before they develop dementia symptoms. DLB is diagnosed when a person develops dementia symptoms within a year or even before they develop motor symptoms of PD.
As with other types of dementia, there is no single test that tells us for sure that a person with Parkinson’s has dementia. Doctors can, however, order an MRI or a CT scan of the brain to see whether there are other structural changes or pathologies that may be causing the symptoms. They will also look at a patient’s medical history and results from a physical examination and memory tests to make their diagnosis.
Signs and symptoms of PDD include the following.
• Changes in memory, concentration, and judgment
• Trouble interpreting visual information
• Muffled speech
• Visual hallucinations
• Delusions, especially paranoid ideas
• Depression and lack of motivation
• Irritability/moodiness and anxiety
• Disorientation
• Sleep disturbances or excessive daytime fatigue
As of this writing, there are no treatments that can cure PDD. The current focus is instead on treating symptoms such as depression, anxiety, and psychotic behavior.
The U.S. Food and Drug Administration (FDA) has approved two types of medications, cholinesterase inhibitors (Aricept, Exelon, Razadyne) and memantine (Namenda), to treat cognitive symptoms of Alzheimer’s disease, and these may help PDD symptoms as well. Antidepressants may be used to treat depression and anxiety. Your doctor may also be able to prescribe medication to help with sleep disturbances (e.g., clonazepam for REM sleep disorder).
Note: Levodopa has been shown to cause confusion and aggravate hallucinations in some people with PDD or DLB. Always consult with your doctor if you notice any new, unusual, or severe symptoms. Antipsychotic drugs should also be used with extreme caution in those with PDD as they may cause serious side effects.