Many of us will recognize the outward motor symptoms of Parkinson's Disease (PD), including tremors and a shuffling gait. However, the non-motor symptoms connected with the cognitive changes in PD may intensify as the disease progresses.
Mild cognitive impairment occurs in 20-50% of people with Parkinson's disease.
Parkinson's disease dementia (PDD) typically occurs several years after the symptoms of Parkinson's begin. 75% of people who live ten years with Parkinson's will develop PDD.
Dementia with Lewy Bodies (DLB) occurs when symptoms of dementia begin close to the time of Parkinson's diagnosis.
Early diagnosis of cognitive impairment and monitoring for the further decline will mean early treatment and intervention to slow the decline.
Therefore, recognizing the subtle differences in cognition early in the progression becomes even more critical. Initiating prompt treatment will improve quality of life and a sense of well-being.
When most people think of cognition, they think of long and short-term memory. However, cognition and cognitive changes incorporate more than just memory.
Attention and Concentration: The ability to concentrate on things like, reading a book or watching a movie.
Language: The ability to actively engage in a conversation.
Executive Functioning: Knowing the steps to complete a task or problem-solving a disruption in the routine.
Visuospatial Skills: The ability to judge the distance when parking your car or making a "mental map" when driving or walking down the street.
Cognitive changes in Parkinson's
The medical community once believed that cognitive changes did not occur until later in the disease. Still, there is more evidence that declining cognition may be present early in the illness.
Sometimes cognitive changes in someone with Parkinson's disease can be mild and not interfere with everyday activities. Mild Cognitive Impairment (MCI) occurs in 20-50% of people with PD, but not all of those with MCI will progress to dementia. Early cognitive screening and ongoing monitoring will help identify early changes in people diagnosed with Parkinson's.
Most often, the symptoms associated with cognitive decline in PD are slower thinking and processing of information, much like the slowness of movement (bradykinesia) characteristic of PD. As a result, they may feel overwhelmed by things like making choices or finding the right word to use in conversation.
Cause of cognitive decline
Parkinson's disease affects several neurotransmitters that are crucial for cognition. Primarily the drop in dopamine is responsible for movement disorders in Parkinson's and does have some mild effects on cognition.
Other neurotransmitters, including norepinephrine, serotonin, and acetylcholine, influence memory and executive function in PD. In addition, the abnormal accumulation of alpha-synuclein proteins as clusters found in brain neurons can cause cognitive impairment in Parkinson’s.
People with PD may also have co-existing vascular changes such as a stroke or Alzheimer's.
Parkinson's disease dementia (PDD)
When the symptoms of cognitive impairment significantly interfere with a person's daily functional activities and routines, they may be moving to a diagnosis of Parkinson's disease dementia (PDD).
Not everyone with Parkinson's develop dementia, but approximately 40% of people do. Typically, the development of dementia occurs over several years after the onset of Parkinson's symptoms. Research shows that 75% of people who live with Parkinson's for ten years will develop dementia.
Lewy Body Dementia
Lewy Body Dementia is a broad term for progressive disorders, including Parkinson's Disease Dementia (PDD) and Dementia with Lewy Bodies (DLB). The two conditions share similar pathology of abnormal brain clusters of alpha-synuclein proteins.
However, a distinguishing factor between the two depends on the onset of symptoms associated with cognitive impairment and Parkinsonian symptoms.
Where PDD occurs over the years following the diagnosis of Parkinson's, DLB happens when the cognitive symptoms of dementia and movement disorders of Parkinson's emerge early or within the first year of symptom onset.
The treatments for cognitive impairment and dementia in PD are like the treatment of dementia without PD. In the MCI stage, strategies are paramount to exercise and keep the mind active. There are also cases where someone's cognition improves. The importance of learning a new skill and maintaining social and family connections can’t be emphasized enough.
Consider an adult day program to increase social engagement and provide respite for the caregiver. There is also growing evidence that supports the benefits of physical exercise.
Any cholinesterase inhibitors, such as donepezil (Aricept) and galantamine (Razadyne), are sometimes used for treatment. Rivastigmine (Exelon) is the only FDA-approved medication for treating dementia in Parkinson's disease.
Memantine (Namenda) is currently investigational for use in PDD. Consult your medical practitioner to determine the best treatment plan for you or your loved one's particular needs.
Tips on how to help your loved one
Sit facing your loved one at their level and make eye contact before speaking. Resist using open-ended questions. Instead, provide prompts to facilitate response. For example, instead of asking, "What did you do today?" ask, "Did you go for a walk today?" or “Did you walk to Target?". Give your loved one time to finish a sentence themselves. When giving a person a list of instructions, verbalize one thing at a time, then write them down. It will be less overwhelming.
Use reminder lists and keep the list in the same place, such as the refrigerator door. Keep things like wallet and keys in the same place. Use reminder alarms on cell phones or smart devices for medications, or use a medication dispenser with an alarm. Add photos on contact entries on a cell phone for face-name recognition.
Consider a counselor with experience in cognitive decline to learn skills to cope with changes and work on future planning. Consider joining a support group, either in person or online, that supports caregivers of people with Parkinson's and or dementia. Contact your local Alzheimer's Association or Parkinson's Foundation for support and direction.
Cognitive changes are common in Parkinson's disease, and while some may develop Mild Cognitive Impairment, not all progress to dementia.
Observation by loved ones who notice the "small changes" and early intervention, treatment, and monitoring will help to optimize your quality of life. Seeking support from loved ones or professionals will provide strategies and can reduce the caregiver's burden.