Mixed dementia means a person has more than one type of dementia at the same time. The most common combination is Alzheimer’s disease with vascular dementia, but other mixes can happen too. This can make symptoms more varied, because memory, thinking, movement, and mood may all be affected in different ways. A diagnosis is usually based on symptoms, medical history, and sometimes brain imaging. Treatment focuses on managing symptoms, supporting daily life, and reducing other health risks that could worsen decline.