Introduction

What is dementia?

Dementia encompasses several conditions all of which affect memory, cognition, and daily living. The most common type of dementia is Alzheimer’s disease but others include:¹

• Vascular dementia: when the brain receives insufficient blood flow due to strokes or small blood vessel issues, causing brain cell damage
• Frontotemporal dementia: when front and side (temporal) brain damage causes dysregulation of emotions, behaviour, and language, which are controlled by these parts of the brain
• Dementia with Lewy bodies: when protein deposits build in the brain affecting thinking, memory, and movement
• Mixed dementia: when more than one type of dementia is present in the same patient

What is mixed dementia?

Mixed dementia describes when more than one type of dementia is present in the same patient. The most common example is the coexistence of Alzheimer’s disease and vascular dementia. In fact, the coexistence of symptoms of Alzheimer’s disease and vascular dementia is so common that some delimit the definition of mixed dementia to only this pair. This article focuses on mixed dementia but you can learn more about the different types of dementia here.^2,3

Mixed dementia is decently prevalent, especially in the more elderly population (>64 years old) with a 22% prevalence rate. Taking into account early onset dementia (<64), prevalence is around 10%.

Specific symptoms can’t be assigned to mixed dementia as they are to other distinct types of dementia, as it is a heterogeneous condition. However, speech and language disorders are common in many types of dementia.^2,3

Dementia and speech difficulties

Speech and language difficulties are present in various subtypes of dementia. In particular, some symptoms of this nature are characteristic of Alzheimer’s disease and vascular dementia, the two most common dementia subtypes. Hence, speech difficulties in mixed dementia can present themselves as symptoms specific to or shared between these. 

Generally, speech difficulties can be of two different natures depending on the brain region affected. The first describes difficulties understanding speech or forgetting the meaning of words. In this case, the brain region affected is called Wernicke’s area. 

The second type involves the execution of speech such as pronunciation. The area affected in this case is Broca’s area. Both types can be present in the same individual and present themselves differently.⁴ 

Oftentimes speech difficulties related to speech execution are further categorised and referred to as apraxia and dysarthria. Apraxia describes difficulty pronouncing sounds and words, while dysarthria involves impairment in the muscles responsible for speech generation. Below are some examples of apraxia and dysarthria:^5,6

• Apraxia: speaking slowly, considerable effort when pronouncing words or sounds, altered or unusual rhythm when speaking, and unnatural intonation 
• Dysarthria: speaking softer or quieter, mumbling, frequent changes in intonation, and speaking in a monotone way

Speech difficulties in mixed dementia 

Here are some of the ways speech difficulties could present themselves in someone with mixed dementia:⁴

• Difficulty finding the correct word for something or naming objects
• Nonsensical or off-topic answers due to lack of comprehension
• Repetition of syllables or words as patients may not remember the pronunciation or a specific word
• Hesitation in speech or slowed speech
• Use related words as replacements. For example “flower” instead of “rose” or “machine” instead of “microwave”
• Use descriptions of words instead of their proper names. For example “the thing you sleep on” instead of “bed” 
• Have fluid speech but use nonsensical words instead of the ones expected 

Treatment of speech difficulties in those with mixed dementia

Treatment of speech difficulties is mostly therapy-based rather than drug-based. Drugs used to “treat speech difficulties” are just those used to treat dementia itself. Currently, there are no drugs that specifically improve speech. However, there are various communication therapy interventions which can improve or prevent/slow the deterioration of speech in dementia.⁷

Speech and language therapy

The following are administered by language therapists: 

• Educational material: Understanding the reasons behind the speech difficulty can help as the patient can attribute the impairment to a specific problem, but also because they have the knowledge to plan and adjust their lifestyle to try and mitigate any issues 
• Specialised reports/reviews: The therapist may detail and summarise the patient’s specific speech difficulties and how they come about
  • Examples include what they often have trouble with and the vocabulary they are more likely to forget 
• Therapy programs: This can be anything from having the person with dementia identify images, to tongue twisters to aid in the pronunciation of specific words

Group therapy and support groups

Having difficulty communicating can be isolating and having someone who understands or is experiencing the same/similar symptoms as the person with dementia can be comforting for them. This is also a good time to exchange ideas and coping strategies. Sharing experiences and understanding that they are not alone can improve mood and motivation to keep trying. People are more likely to make friends and this can also evolve into practice outside of the program in a more informal and comfortable environment.¹

Often the person with dementia is also accompanied by a caregiver. This is also a good opportunity for them to share experiences and advice with other caregivers. Support for those who care for people with dementia is crucial considering the burden and responsibility they have, most of the time without monetary compensation. Caregiving can be difficult especially with dementia, as the person may be unaware or forget the caregiver’s kindness and act wary or disrespectful. 

Living with someone with mixed dementia and speech difficulties

Living with and caring for someone with mixed dementia can be challenging for varied reasons including lack of or impaired communication. There are many programs and organisations that provide support for the caregiver and the person with dementia through different approaches ranging from educational material to counselling and therapy. Below we provide a list of suggestions to help communicate with someone with speech difficulties that they develop as a result of mixed dementia:

• Be patient and respectful. It can be stressful and frustrating not being able to communicate as desired. Empathise with the person with dementia and try to approach them how you would like to be treated if in their shoes 
• Make the person comfortable and make sure they can pay attention to the conversation 
• Make enough time for the conversation to occur without stress
• Make sure you are visible to the person with dementia and speak clearly without shouting
• Make small pauses after describing ideas to help them integrate the information 
• When they speak, pay attention and try not to interrupt them. Let them finish their point and try not to assume you know what they mean before they finish
• If you don’t understand what they said, ask them to repeat it. If you still don’t understand, explain to them what you have grasped. This way they can try to correct you
• Use simple vocabulary and try to formulate questions which are easy to answer like yes or no questions
• Try to stick to one topic or idea at a time 

FAQs

What stage of dementia affects speech?

Speech and language difficulties usually become a problem during moderate and severe dementia. In the earlier stages, communication is mostly fluid, however, faculties tend to break down more noticeably in later stages. 

Specifically in severe dementia, the person with dementia is unable to communicate verbally to their carers and other medical staff. This is why several programs strive to ask and record how the person with dementia would like to communicate during later stages when the conversation becomes difficult. 

How does mixed dementia affect communication?

Mixed dementia can affect communication in two major ways: memory and execution. Dementia is characterised by memory problems, which not only include facts but also the meaning of words. This can cause the person with dementia to misuse words, describe words they don’t remember, or use a different word altogether. Oftentimes, the less frequently used words will be forgotten first, whereas the more common ones will be affected at later stages of dementia.⁴

The second aspect concerns execution. The brain has a specific area for speech execution which can be impaired during dementia. Due to this, people with mixed dementia can mumble, slur their words, have irregular intonation and pronunciation, and take more effort than normal when trying to pronounce specific things. 

Which dementia causes speech problems?

All types of dementia may affect speech and language simply due to the effects dementia has on memory. However, specific subtypes of frontotemporal dementia are most associated with these types of problems. Progressive non-fluent aphasia mostly affects speech execution, while semantic dementia is more related to difficulties in comprehension and remembering vocabulary.⁸ 

Summary

Mixed dementia is the coexistence of symptoms of more than one type of dementia, commonly Alzheimer’s disease and vascular dementia. The speech difficulties in mixed dementia are heterogeneous due to the nature of the condition. Commonly, patients will forget words and their meanings and/or will have pronunciation difficulties. 

Targeted treatment is therapy-based and will involve a language therapist who will help the patient with personalised exercises to aid in memory and articulation. Support groups can also help the person with dementia as they may feel isolated and misunderstood. If you are living or trying to communicate with someone with mixed dementia and speech difficulties, be sure to show patience, empathy and respect when conversing. Not being able to communicate as desired can be frustrating, so we should try our best to make them comfortable.