Parkinson's Disease And Dementia
There are many diseases, both serious and mild, that affect the elderly much more often than younger people. Sometimes, one disease can cause another, or two seemingly unrelated diseases might be linked.
This may be the case with Parkinson’s disease and dementia; it is estimated that approximately 50 to 80 percent of those with Parkinson’s disease will eventually develop at least mild dementia, while up to 20 percent will develop full-blown dementia. Symptoms of dementia may not be apparent until up to a decade after a Parkinson’s diagnosis.
What is Parkinson’s Disease?
Parkinson’s disease is a progressive nervous system disease that affects movement. Symptoms include tremors, slowed movement, writing changes, speech changes, loss of automatic movement and impaired posture and balance.
It is caused by the loss of neurons that produce the neurotransmitter dopamine, which helps control muscle movement. However, it is currently unknown what causes the death of these cells.
There is no cure for Parkinson’s, but symptoms can be treated with medication like L-dopa, a synthetic form of dopamine. Although Parkinson’s can develop in adults as young as 30, it most often develops after age 50.
Parkinson’s Disease Dementia
Like with other forms of dementia, there is no definitive test for Parkinson’s disease dementia; a patient is diagnosed with Parkinson’s disease dementia if they exhibit symptoms such as impairment in concentration, memory or judgment, depression, sleep disturbances, irritability, apathy or
disorientation; and have been diagnosed with Parkinson’s disease at least a year prior.
Symptoms must also be severe enough to impair daily life. Although these symptoms differ slightly from symptoms of other forms of dementia, these other forms, such as Alzheimer’s disease, need to be ruled out first, especially because age is a risk factor for both Parkinson’s and most forms of dementia.
Other strong predictors of developing dementia with Parkinson’s disease include being male and having visual hallucinations. Parkinson’s disease dementia progresses much like other forms of dementia, and does not have a cure.
Lewy Bodies And Parkinson’s Disease Dementia
Lewy bodies are abnormal deposits of a widely-found brain protein (alpha-synuclein) that build up over time. These deposits are found in multiple related disorders, including dementia with Lewy bodies, Alzheimer’s disease and Parkinson’s disease.
It’s unclear what causes Lewy bodies to form, but in patients with Parkinson’s, they appear in dead and dying neurons. When Parkinson’s is diagnosed before dementia symptoms appear, the condition is known as Parkinson’s disease dementia. When dementia symptoms begin to appear around the same time as motor symptoms, the disease is known as Lewy body dementia. Despite the different initial onset of symptoms, these two forms of dementia progress in very similar, if not identical, ways.
Therefore, many doctors and researchers consider Lewy body dementia and Parkinson’s disease dementia to be different expressions of the same underlying disease.