Mixed dementia occurs when someone has more than one type of dementia. And, although that term isn’t typically used in conversations about dementia, some studies suggest that the mixed variety is in fact the most common form of dementia in older adults. Typically, it’s a combination of Alzheimer’s disease and a form of cerebrovascular disease such as a stroke; a person may also have Lewy body dementia, which occurs when an abnormal amount of a certain protein (tau) accumulates in the brain.
The mixed type of dementia can only be definitively diagnosed after a person’s death because an autopsy needs done for its confirmation. The autopsy would need to identify more than one type of abnormality, such as brain vessel blockages and/or a buildup of tau protein.
Researchers are still trying to determine how diseases involved in mixed dementia influence one another. Plus, it is not yet known if symptoms are worse when someone has multiple forms of dementia versus one type. It is anticipated that, as advances in research and imaging methodologies are made, this type of dementia will be able to be diagnosed while the person is still living.
Symptoms of Mixed Dementia
According to the Alzheimer’s Association, symptoms of mixed dementia vary from person to person, depending upon what brain regions are affected and what brain changes have taken place. Often, these symptoms are indistinguishable from Alzheimer’s disease, although symptoms may progress more quickly when multiple forms of dementia exist and/or appear earlier.
The most common early symptom of Alzheimer’s is “difficulty remembering newly learned information because Alzheimer's changes typically begin in the part of the brain that affects learning.” As the disease advances, symptoms become more severe, including this list from the Alzheimer’s Association:
- mood and behavior changes
- deepening confusion about events, time and place
- unfounded suspicions about family, friends and professional caregivers
- more serious memory loss and behavior changes
- difficulty speaking, swallowing and walking
No drugs exist that specifically treat a mixed form of dementia, although people with this condition may respond favorable to medications prescribed for Alzheimer’s disease.
Mixed Dementia Risk Factors
According to multiple studies, major risk factors for Alzheimer’s disease may also be the same as vascular disease risk factors. A National Institute on Aging article lists the following factors:
- Patterns of disease in the family health history; to look for patterns, review known health facts from three generations: grandparents, parents and children
- Lifestyle habits, which include but are not limited to smoking and exercise
- Where family members grew up, and under what conditions
There is a test to determine if someone has gene changes associated with familial Alzheimer’s disease, with onset when someone is in his or her 30s-60s; there is not yet a test for late-onset Alzheimer’s, which typically has its onset in a person’s mid-60s.
For More Information
You can read this article by TheAdvocate.com and this one by the National Institute of Aging. You can also call the Alzheimer’s Association’s 24/7 helpline at 800-272-3900 and/or find information in their virtual library. You can sign up for a weekly e-newsletter to receive information about the latest advances in research and treatment, locate a local chapter in your community and join an online community.