Mixed dementia occurs when changes in the brain are associated with more than one type of dementia at the same time.
Most commonly, vascular dementia is characterized by plaques and tangles linked to Alzheimer’s disease, as well as changes in blood vessels. Lewy body dementia and Parkinson’s disease dementia can often coexist with plaques and tangles of Alzheimer’s. It is possible, however, that a person may develop changes linked to all three – Alzheimer’s, vascular dementia and Lewy body dementia.
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Mixed dementia causes
Although it is uncommon to diagnose mixed dementia during life, many researchers believe it should be given more attention since the brain changes associated with several dementia types may be more devastating than those caused by just one type of dementia. There is evidence that a person is more likely to develop dementia symptoms if they show more than one type of dementia-related change.
Mixed dementia symptoms
Different types of dementia may produce different symptoms of mixed dementia, depending on the type of brain damage and the affected brain regions. Symptoms can sometimes look like Alzheimer’s or another form of dementia, or even be indistinguishable from them. There is also the possibility that a person may be suffering from more than one type of dementia. The relationship between cognitive function and underlying brain abnormalities will continue to shed light on mixed dementia through long-term studies.
How common is mixed dementia?
A review of autopsy studies examining the brains of people with dementia suggests that the majority of those 80 and older likely had “mixed dementia” as a result of Alzheimer’s disease and vascular dementia. The most common cause of dementia in the elderly appears to be mixed vascular and degenerative.
There may not be a clear distinction between whether a patient with mixed dementia displays symptoms of Alzheimer’s or another form of dementia. 40 percent of people with Alzheimer’s who were autopsied also had cerebrovascular disease, according to one study. A number of studies have found that factors associated with vascular disease can also be associated with Alzheimer’s disease.
There is still much to learn about the complex interplay between the underlying diseases in mixed dementia. People with multiple types of dementia may experience worse symptoms when their brains are affected by these changes. However, the outlook is generally positive.
If multiple disease processes occur simultaneously during the course of a person’s illness, then the treatment outcome will likely be poor.
Additionally, it is uncertain whether a person with multiple dementias can be helped by treating one type of dementia at a time, for example, by controlling high blood pressure and other risk factors associated with vascular diseases. However, the better the treatment outcome for the patient is if we are able to control other health conditions.
Researchers think mixed dementia deserves more attention even though it is a rare diagnosis. In other words, dementia-related brain changes occurring in combination with one another may have a more significant impact on the brain than dementia alone. A person’s chances of developing symptoms of dementia appear to be increased if more than one type of dementia-related alteration exists. More than three times as likely is being diagnosed if you have symptoms of more than one type of dementia.
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Most people who have mixed dementia are diagnosed with another type of dementia during life. Alzheimer’s disease is the most common type of dementia that occurs during life. NIA study participants diagnosed with dementia were 94% likely to have Alzheimer’s disease, as measured by long-term cognitive assessments followed by brain autopsies.
Although, autopsies of Alzheimer’s patients revealed 54% had coexisting pathology as well as hallmarks of the disease. A blood clot or other vascular evidence, previously undetected, was the most common coexisting abnormality. In addition, the presence of Lewy bodies was relatively common.
Prevalence of mixed dementia
This debilitating condition is difficult to estimate. Patients have traditionally been diagnosed with Alzheimer’s disease or vascular dementia when they have one primary type of dementia.
In recent years, however, researchers have discovered that many people whose symptoms are indicative of one form of dementia may also exhibit symptoms of another. It is not uncommon to observe signs of Alzheimer’s, vascular dementia, and Lewy body dementia in conjunction with each other during autopsies after death.
According to a study, 94% of participants had Alzheimer’s disease. 54% of those with dementia had other types of dementia, such as blood clots (vascular dementias) or Lewy bodies (Lewy body dementias).
Age is a risk factor for many forms of dementia, and it may lead to mixed dementia more often as people age.
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What are the treatments for mixed dementia?
No treatment exists for mixed dementia. A better level of cognitive function for longer can be achieved with the use of drugs and other treatments. The damage that already has occurred in the brain is not prevented by these treatments.
Medication for mixed dementia
Treatment for mixed dementia typically involves cholinesterase inhibitors. A chemical that is responsible for cell communication is increased in the brain by these substances. The symptoms of vascular dementia can’t currently be improved by medication. If a person with vascular disease continues to take their medication for high blood pressure or diabetes, they may be able to prevent strokes or other events.
Other therapies for mixed dementia may also help to improve the quality of life or function of the patient as well as drug treatments. These therapies include cognitive behavioral therapy, cognitive stimulation therapy, cognitive rehabilitation and reminiscence therapy. Physiotherapy can be offered to a person with Lewy body dementia to aid with movement problems.
Researchers think we’ll reduce the number of people with dementia if we better understand mixed dementia and realize vascular changes are the most common brain change that occurs with it. We can prevent brain vascular changes by lowering our risk factors for heart and blood vessel diseases (like blood pressure, cholesterol, weight and diabetes).