Mixed Dementia

Mixed dementia refers to a condition where multiple causes of dementia occur simultaneously, leading to brain changes associated with different types of dementia occurring together.

About

The most common form of mixed dementia involves the presence of abnormal protein deposits linked to Alzheimer’s disease along with blood vessel problems associated with vascular dementia. Additionally, Alzheimer’s brain changes often coexist with Lewy bodies. In some cases, individuals may have brain changes related to all three conditions: Alzheimer’s disease, vascular dementia, and dementia with Lewy bodies.

The exact prevalence of mixed dementia among older adults with a specific dementia diagnosis is not known, but autopsies suggest that it may be more common than previously thought. Autopsy studies play a crucial role in understanding mixed dementia because most dementia-related brain changes cannot be measured in living individuals. Through post-mortem brain analysis and correlating cognitive health with diagnosed conditions during life, researchers gain insights into mixed dementia.

Causes and Risk Factors

While mixed dementia is not frequently diagnosed during life, researchers believe it deserves more attention due to the potentially greater impact on the brain when multiple types of dementia-related brain changes coexist. Evidence suggests that having multiple types of dementia-related changes increases the likelihood of developing symptoms.

Symptoms

The symptoms of mixed dementia can vary depending on the types of brain changes and affected regions. In many cases, the symptoms may resemble those of Alzheimer’s or another form of dementia, making it difficult to distinguish. However, in some instances, symptoms may suggest the presence of multiple types of dementia. Continued long-term studies are expected to provide a better understanding of the symptoms associated with mixed dementia.

Diagnosis

Most individuals diagnosed with mixed dementia during autopsies were initially diagnosed with a specific type of dementia, primarily Alzheimer’s disease. For instance, in a study involving cognitive assessments followed by brain autopsies, the majority of participants diagnosed with dementia were diagnosed with Alzheimer’s. However, the autopsies revealed that more than half of those diagnosed with Alzheimer’s had coexisting pathology, such as vascular disease or Lewy bodies.

Outcomes and Treatment

Since most people with mixed dementia are initially diagnosed with a single type of dementia, treatment decisions are typically based on the diagnosed type. Currently, there are no drugs specifically approved by the FDA for treating mixed dementia. However, physicians may consider prescribing FDA-approved drugs for Alzheimer’s if they suspect its involvement. Researchers believe that gaining a deeper understanding of mixed dementia, particularly the prevalence of vascular changes, may present opportunities for dementia prevention. Controlling risk factors for heart and vascular diseases may also help protect the brain from vascular changes.