Mixed dementia occurs when more than one type of dementia-related brain change is present at the same time. In many cases, the changes characteristic of Alzheimer’s disease coexist with the blood-vessel damage associated with Vascular Dementia.
Other combinations – such as Alzheimer’s plus Lewy body dementia – are also possible.
What causes it
Mixed dementia emerges when two or more pathological processes occur at the same time in the brain. Examples of mixed dementia include:
- The amyloid plaques and tau tangles of Alzheimer’s disease alongside vascular damage such as small-vessel disease or past strokes.
- Alzheimer’s disease changes together with Lewy bodies or Parkinsonian forms of dementia.
Because the mixed-type pathology often reflects age-related accumulation of different brain injuries, the prevalence of mixed dementia rises with advanced age.
Common symptoms of mixed dementia
Because mixed dementia involves multiple types of pathologies, its symptom profile may vary widely. Often, symptoms mimic those of Alzheimer’s or vascular dementia or another form, which means the person may show a blend of features. Common symptoms include:
- Memory decline, especially in forming new memories
- Problems with planning, judgment or multi-tasking
- Slowed thinking or difficulty concentrating
- Confusion
- Difficulty with walking, balance, or coordination
- Sudden or step-wise worsening of brain function
How it’s diagnosed and treated
Identifying mixed dementia is challenging, because most standard clinical tests cannot clearly separate overlapping disease processes. Imaging may show both neurodegenerative changes and vascular damage. Typically, to assess the possibility of mixed dementia, a clinician will look at:
- History of cognitive and functional decline
- Brain imaging (MRI/CT) showing degenerative and vascular changes
- Stroke history or brain-blood-vessel damage
- Cognitive testing showing mixed features
There is no treatment approved specifically for mixed dementia. Care for mixed dementia typically focuses on addressing treatable risk factors (e.g., blood pressure, cholesterol, diabetes, and smoking in vascular dementia), which might slow progression of disease, or using symptomatic treatments for Alzheimer’s disease when appropriate (e.g., cholinesterase inhibitors). Support through cognitive behavioral therapy, cognitive rehabilitation therapy, or speech therapy is also common to help individuals stay independent for as long as possible.
Learn more about the different types of dementia
Mixed dementia is a common yet complex form of dementia in which more than one underlying disease process is acting together in the brain. You can learn more about the different conditions below:
- Alzheimer’s disease
- Vascular dementia
- Lewy body dementia
- Parkinson’s disease dementia (PDD)
- Frontotemporal degeneration (FTD)
- Corticobasal degeneration
If you or a loved one have a confirmed or suspected dementia diagnosis, and you suspect multiple contributing factors, talk with a dementia-experienced healthcare professional about the possibility of mixed dementia.