Are all dementias alike? No, not at all. Some develop in people who have specific conditions. This particular sharepost will focus on one of these types, Parkinson’s disease dementia.
Parkinson’s Disease Dementia
First of all, let’s look at what Parkinson’s disease dementia is. Parkinson’s disease affects approximately two percent of people who are older than age 65; it is estimated that one million people in the United States have this particular disease. Furthermore, between 50-80 percent of those with Parkinson’s disease eventually develop Parkinson’s disease dementia. Furthermore, the Parkinson’s Disease Foundation reports that 25 percent to 33 percent of people with Parkinson’s disease have symptoms of mild cognitive impairment.
The Alzheimer’s Association defines Parkinson’s disease dementia as in an impairment in thinking and reasoning that eventually affects many people who have Parkinson’s disease. People who have both Parkinson’s disease and Parkinson’s disease dementia have abnormal microscopic deposits that are made up of a protein called alpha-synuclein. These deposits, which are known as Lewy bodies, are found widely in the brain; however, researchers have not determined the normal function of these proteins.
Studies suggest that there may be a link between Parkinson’s disease, Parkinson’s disease dementia and dementia with Lewy bodies due to an underlying abnormality in how the brain processes alpha-synuclein. “Another complicating factor is that many people with both dementia with Lewy bodies and Parkinson's disease dementia also have plaques and tangles – hallmark brain changes linked to Alzheimer’s,” the Alzheimer’s Association reports.
Study Evaluates Chance of Developing Parkinson's Disease Dementia
Researchers who study Parkinson’s disease and Parkinson’s disease dementia have developed an assessment that may help identify signs of cognitive impairment early, thus increasing the possibility that health care professionals may be able to slow the onset of dementia. The assessment, which was developed by the Movement Disorder Society Task Force, includes tests on attention span, verbal memory, spatial skills and executive functioning.
A recent study focused on this assessment involved 182 people who lived in Norway who had been recently diagnosed with Parkinson’s disease. These participants had not developed dementia and were not taking medication at the start of the study. At the time that each participant was diagnosed with Parkinson’s disease, he or she also was tested for mild cognitive impairment. Thirty-seven participants were found to have this this type of impairment.
During the first and third year of the study, the researchers used the newly developed assessment to test each participant. They found that 27 percent of the participants who had been diagnosed with mild cognitive impairment at the start of the study had developed Parkinson’s disease dementia by the third year. In comparison, only one person of the group who did not have mild cognitive impairment at the start of the study had developed Parkinson’s disease dementia by the third year.
Furthermore, researchers found that 45 percent of participants who experienced mild cognitive impairment at the time of their diagnosis of Parkinson’s disease as well as at the one-year mark were diagnosed with Parkinson’s disease dementia by the third year.
Surprisingly, two participants who experienced mild cognitive impairment at the time of their Parkinson’s disease diagnosis as well as a year later did not have cognitive impairment or dementia at year three. The researchers found that participants who were diagnosed with mild impairment during the first year of the study but who did not develop dementia by the third year were much younger (an average age of 69.4 years) than those who developed dementia (an average of 74.9 years).
The study’s findings indicate that people who have Parkinson’s disease who are not diagnosed with mild cognitive impairment are unlikely to develop dementia during the following three years. Furthermore, mild cognitive impairment can help predict future dementia in people who have Parkinson’s disease. However, the researchers also found that the prediction is more accurate if the patient tests positive several times for mild cognitive impairment.
Primary Sources for This Sharepost:
Alzheimer’s Association. (nd.). Parkinson’s disease dementia.
Parkinson’s Disease Foundation. (2013). Predicting dementia in early Parkinson’s disease.
Published On: April 26, 2013