Mixed dementia is a disease in which abnormalities characteristic of more than one type of dementia occur simultaneously. 

Doctors may also call mixed dementia « dementia – multifactorial. »  

In the most common form of mixed dementia, the abnormal protein deposits associated with Alzheimer’s disease (amyloid proteins) coexist with blood vessel problems related to vascular dementia. Alzheimer’s brain changes often coexist with the Lewy body. In some cases, a person may have brain changes related to all three forms of dementia: Alzheimer’s disease, vascular dementia,  and Lewy body dementia.

Researchers don’t know exactly how many older people currently diagnosed with a specific type of dementia actually have mixed dementia, but autopsies show the condition may be much more common than previously realized.

Autopsy studies play a key role in shedding light on mixed dementia because scientists cannot yet measure most dementia-related brain changes in living individuals. 

In the most informative studies, researchers correlate any problem diagnosed during the participant’s lifetime with analysis of their brain after death. 

In a study conducted in the United States, data from the first 141 volunteers showed that more than 50% of those whose brains met the criteria for Alzheimer’s disease also had at least one other type of dementia.

Symptoms of Mixed Dementia

Symptoms can vary depending on the types of brain changes involved and the brain regions affected. 

In many cases, the symptoms may be similar or even indistinguishable from those of Alzheimer’s disease or another type of dementia. In other cases, a person’s symptoms may suggest the presence of more than one type of dementia.