This is a dementia in which there is a coexistence of abnormal characteristics of more than one type of dementia. The most common type of mixed dementia is the one which has characteristics of both Alzheimer’s disease and vascular dementia. In some types of mixed dementia there is the coexistence of Alzheimer ‘s disease and DLB.
Autopsy is the only means to establish the coexistence of two dementias. It is important to recognize mixed dementias because the combination of the two diseases may have a greater impact on the brain than either by itself.
The NIA funded memory aging project has revealed some initial data about mixed dementia and warns it is very common. Data from 141 volunteers have shown that 50% of them who met the criteria for Alzheimer disease had pathological evidence of one or more coexisting dementias. This study is conducted by the Rush Alzheimer’s Disease Center and the Rush Institute for Healthy Aging in Chicago and funded by the National Institute on Aging (NIA).
Many researchers are convinced that growing understanding of mixed dementia, coupled with recognition that vascular changes are the most common coexisting brain change, may create an opportunity to reduce the number of people who develop dementia. Controlling overall risk factors for diseases of the heart and blood vessels — such as blood pressure, cholesterol levels, body weight and diabetes — may also protect the brain from vascular changes. This protection may help avoid the double impact from vascular changes and other dementia- related abnormalities that seems to increase the risk of being diagnosed with dementia.