Mixed dementia

Mixed dementia is a condition in which you have more than one type of dementia at the same time. The most common form is a combination of Alzheimer’s disease and vascular dementia. Dementia can cause problems with memory, language, emotions, and how you think and behave.

Causes of mixed dementia

Dementia is caused by diseases or conditions that damage brain cells so that the brain no longer works properly.

These causes may include:

• Alzheimer’s disease
• Lewy body disease
• Parkinson’s disease
• stroke, causing vascular dementia
• cancer affecting the brain
• a brain injury

If you have mixed dementia, your brain shows changes of two or more types of dementia.

• Alzheimer’s disease is caused by an abnormal build-up of proteins in the brain. This causes blockages and tangles in brain cells. It affects how the cells work, communicate, and repair themselves.
• Vascular dementia is caused by diseased or damaged blood vessels. This reduces the blood flow to the brain. It may be caused by strokes or mini-strokes.
• Dementia with Lewy bodies is caused by tiny clumps of protein (Lewy bodies) building up in nerve cells in your brain. This can affect movement. Lewy bodies also build up in Parkinson’s disease.

Dementia is more common as people get older. Certain things may make you more likely to develop dementia. These risk factors depend on which form of dementia you have. You may be more likely to develop some types of dementia if you:

• have high blood pressure
• have high blood cholesterol
• have blood vessel damage in your brain
• have diabetes
• are overweight in middle age
• smoke

Symptoms of mixed dementia

Mixed dementia symptoms vary from person to person. You’ll have symptoms of more than one type of dementia at the same time. These symptoms often depend on which part of your brain is affected – and by which type of dementia. If you have two or more types of dementia, your symptoms may be worse and more noticeable than if you had just one type of dementia. Your symptoms may also seem to progress more quickly.

Common symptoms of dementia include:

• memory problems
• personality and mood changes
• problems with concentration and decision-making
• problems with walking and balance, which increase the risk of falls
• anxiety
• depression
• agitation and aggression
• sleep problems, such as insomnia
• loss of bladder control (incontinence)
• fits (seizures)

Vascular dementia symptoms often occur after a stroke or several strokes. Memory loss is common in the early stages of Alzheimer’s disease, but may not be the main symptom in early vascular dementia.

Symptoms of dementia with Lewy bodies may also include:

• seeing or hearing things that aren’t there (hallucinations)
• sudden confusion, or ‘switching off’
• restless, disturbed sleep, with vivid dreams
• speech problems
• movement difficulties similar to Parkinson’s disease, such as tremor (shaking), spontaneous movements, and muscle stiffness

Frontotemporal dementia symptoms may include:

• changes in behaviour and personality
• speech problems
• difficulty understanding the meaning of words
• problems recognising familiar faces or objects
• movement difficulties

Diagnosis of mixed dementia

Diagnosing dementia in the early stages can be difficult as early symptoms can be hard to spot and begin slowly. Mixed dementia can be particularly difficult to diagnose because the symptoms are so varied.

Early symptoms of dementia are often more noticeable to friends and family than to the person themselves. So doctors who are diagnosing dementia need as much information as possible from the people who see the person regularly. Relatives and friends may be able to give more accurate information about what has changed and when they first noticed the dementia symptoms.

The doctor will want to know whether anyone else in the family has had any form of dementia. They may ask about any other medical conditions they have and medicines they’re taking.

A doctor may use a special questionnaire or tool to assess the symptoms. They’ll ask about:

• memory problems and confusion
• behaviour and mood changes – whether they’re more depressed, anxious, or angry than normal
• the effect on normal daily activities – such as cooking, housework, and bathing

The doctor will also need to carry out an examination and do some basic tests, such as blood tests, and sometimes urine tests. This rules out other possible causes of the symptoms.

If your GP suspects dementia, they’ll refer you (or your relative) to the local memory clinic run by the older persons’ mental health team for more assessment. You (or your relative) may then be referred to a specialist psychiatrist or specialist in diseases of the brain and nervous system (a neurologist) if the dementia symptoms are unusual or the diagnosis isn’t clear.

The specialist will carry out more tests. They may suggest a brain scan, such as:

• computer tomography (CT) scan
• magnetic resonance imaging scan (MRI) scan
• positive emission tomography (PET) scan

Outlook of mixed dementia

Being diagnosed with dementia is upsetting and worrying. There’s also a lot of information to read and a lot to think about. So you need time to take in the news.

If you or a loved one has been given a dementia diagnosis, it’s important to know you’re not alone. You can get support from specialist dementia support workers, counsellors, and support groups. If you’re struggling, speak to a counsellor or psychotherapist. It’s important that family members and carers look after their own physical and mental health too.

Knowing what to expect after a dementia diagnosis can help you plan ahead and find ways to cope. Someone with dementia is likely to need a lot of care as their symptoms get worse. They may eventually need residential care.

How long someone may live with dementia differs from person to person and is difficult to predict.