What is mixed dementia? Symptoms, causes and treatment 

Mixed dementia is a condition where two or more types of dementia occur together, which often makes it challenging to diagnose and manage. A person with mixed dementia will experience a combination of the symptoms associated with the types of dementia they have.

Our dementia specialist Admiral Nurses explain the most common types of mixed dementia, symptoms to look out for and strategies for managing the condition.

Types of mixed dementia

Mixed dementia can involve any type of dementia. However, the most common forms are Alzheimer’s disease with vascular dementia and Alzheimer’s disease with Lewy body dementia.

Alzheimer’s disease with vascular dementia

The most common form of mixed dementia is a combination of Alzheimer’s disease and vascular dementia. The person will have symptoms of both forms.

Some of the most common symptoms of early Alzheimer’s disease include:

• forgetting recent events or conversations
• misplacing items or putting them in the wrong place (eg putting their keys in the fridge)
• forgetting the names of people, objects or places
• struggling to find the right words
• repeating themselves

Some of the most common early symptoms of vascular dementia include:

• concentration problems
• difficulty with planning and decision-making
• slowed thought processes

Alzheimer’s disease and Lewy body dementia

When Alzheimer’s disease occurs in combination with Lewy body dementia, symptoms of both will overlap.

Some of the most common symptoms of Lewy body dementia include:

• recurring visual hallucinations – seeing things that are not there
• sleep disturbances
• sudden changes and fluctuations in alertness

Common symptoms of early stage Alzheimer’s disease include:

• forgetting recent events or conversations
• misplacing items or putting them in the wrong place (eg putting their keys in the fridge)
• forgetting appointments
• forgetting the names of people, objects or places
• struggling to find the right words
• repeating themselves

How common is mixed dementia?

Mixed dementia is most common in people over 75 and accounts for at least 10% of all dementia diagnoses.

Causes and risk factors of mixed dementia

For mixed dementia that involves Alzheimer’s disease and vascular dementia, the main risk factors are older age, high blood pressure and blood vessel damage in the brain. Find out more about causes and risk factors of dementia.

Symptoms of mixed dementia

The symptoms of mixed dementia vary depending on the types of dementia involved and the areas of the brain that are affected. The person will experience symptoms of each type of dementia that they have. These might include:

• memory problems
• difficulty with attention and concentration
• struggling with problem-solving and decision-making
• communication challenges
• changes in personality, behaviour and mood
• sleep disturbances
• hallucinations

Our pages on types of dementia have more information about the symptoms specific to each form of the condition.

Diagnosing mixed dementia

Mixed dementia can be challenging to diagnose because the person will experience symptoms of more than one type. This may mean that the person is diagnosed with the wrong type of dementia, or with a single form, whereas they actually have two or more. This could impact the treatment and support they receive.

The first step towards getting a diagnosis is to see a GP, who will carry out some initial health checks and basic assessments of memory. If the GP suspects the person has dementia of any type, they should be referred for further assessment, usually with a memory clinic. To accurately diagnose mixed dementia, the healthcare professional will need specialist knowledge of the different types of dementia and their symptoms.

Treatment for mixed dementia

There is currently no cure for dementia, and no way to prevent it from progressing. However, there are various strategies, including medication, therapies and support, that can help with managing the symptoms.

Medication

If a person has mixed dementia that includes Alzheimer’s disease and is in the early to middle stages, they may be prescribed medication to help with managing the symptoms and slowing the progression. The most commonly prescribed are donepezil, rivastigmine or galantamine. However, these are not suitable for everyone with mixed dementia involving Alzheimer’s disease; for example, if the person also has frontotemporal dementia, it could make their symptoms worse.

Some people may be prescribed medication for other health conditions that are linked to their dementia. For example, vascular dementia may be caused by problems such as high blood pressure, high cholesterol, type two diabetes or strokes, so if a person has mixed dementia that includes vascular dementia, they may be given medication for these conditions.

Therapies

There are a number of therapies that may help improve a person with dementia’s quality of life or abilities. Some of these are:

• occupational therapy: this involves learning new ways to manage everyday tasks that have become difficult
• talking therapies: these might be recommended if the person is experiencing anxiety or depression related to their diagnosis
• cognitive stimulation therapy: activities and exercises aimed at improving memory, thinking and concentration, often in a group setting
• reminiscence therapy and life story work: talking about memories and creating a record of the person’s life, which can encourage communication and conversation, stimulate the mind and help other people understand the person better
• cognitive rehabilitation: working with a therapist to relearn skills that the person has lost, or develop new ones
• music or art therapy: these can be relaxing, promote wellbeing and provide alternative ways to communicate if verbal communication has become difficult
• physiotherapy: this aims to improve physical function, reduce the risk of falls and help the person recover from an injury. It is most commonly used for people with Lewy body dementia, who typically have problems with movement

Lifestyle changes

Making lifestyle changes and ensuring conditions like heart disease, high blood pressure and diabetes are well managed can help the person with mixed dementia stay as well as possible, maintaining their quality of life and independence. You could support the person to:

• eat a balanced, healthy diet: the NHS Eatwell Guide is a useful tool to help you understand the basics of eating healthily
• take exercise, according to their abilities
• lose weight if they are overweight, or otherwise maintain a healthy weight; calculating their body mass index (BMI) will indicate a suitable weight range for the person’s height
• not exceed 14 units of alcohol per week
• stop smoking, if they are a smoker

Progression of mixed dementia

It is very difficult to predict how quickly someone’s dementia will progress. However, dementia is often classified in three stages: early, middle and late. The speed at which dementia progresses will depend on factors like:

• the person’s age
• the type/s of dementia they are diagnosed with
• any treatment or management strategies they are using
• their lifestyle

If the person has two types of dementia the symptoms can be more noticeable and appear to progress more rapidly.

Research indicates that mixed dementia is often not recognised or misdiagnosed, which may lead to the person missing out on treatment and support that could be helpful to slow the progression of their specific form of dementia or make it more manageable.

How we can support you

If you are living with dementia or caring for someone with the condition, register for our free online sessions, ‘Dementia: what next?’.

To speak to a dementia specialist Admiral Nurse, call our free Dementia Helpline on 0800 888 6678 (Monday-Friday 9am-9pm, Saturday and Sunday 9am-5pm, every day except 25th December) or email helpline@dementiauk.org.

If you prefer, you can book a phone or video call with an Admiral Nurse at a time to suit you.