Dementia - Different Forms of the Disease

Dementia - Different Forms of the Disease

Dementia is not a disease in itself. Dementia is a word used to describe a group of symptoms that occur when brain cells stop working properly. Read on to learn about the many different forms of the disease.

It is possible to have more than one type of dementia at the same time. Alzheimer’s is sometimes seen with vascular dementia or dementia with Lewy bodies. You might hear this called ‘mixed dementia’. 

  • Alzheimer’s Disease

The most common form, often develops slowly over several years. It is not always obvious to begin with and symptoms can be subtle and overlap with other illnesses such as depression.

In the early stages, it can sometimes be difficult to distinguish Alzheimer’s from mild forgetfulness which can be seen in normal ageing.

Typical early symptoms of Alzheimer’s may include:

  • Regularly forgetting recent events, names and faces.

  • Becoming increasingly repetitive, e.g. repeating questions after a very short interval.

  • Regularly misplacing items or putting them in odd places.

  • Uncertainty about the date or time of day.

  • A person becoming unsure of their whereabouts or getting lost, particularly in unusual surroundings.

  • Problems finding the right words.

  • Becoming low in mood, anxious or irritable, losing self-confidence or showing less interest in what’s happening.

  • Vascular Dementia

The second most common cause of dementia that can occur when blood flow to the brain becomes reduced. Symptoms can include memory loss, disorientation and problems with communication. Other symptoms may include:

  • Thinking skills – taking more time to process information and having problems with attention, planning and reasoning.

  • Personality changes – these may include depression and apathy (becoming less interested in things). People may also become more emotional.

  • Movement problems – difficulty walking or changes in the way a person walks.

  • Bladder problems – frequent urge to urinate or other bladder symptoms. This can be common in older age, but can be a feature of vascular dementia when seen with other symptoms. 

  • Dementia with Lewy Bodies

The third most common form, DLB can cause common dementia symptoms including memory loss, spatial awareness problems and a decline in problem solving skills.

There are also some more specific symptoms associated with the disease. Some of these symptoms are also seen in Parkinson’s dementia and may include:

  • Changes in alertness, attention and confusion, which may be unpredictable and change from hour to hour or day to day.

  • Parkinson’s disease-type symptoms such as slowed movements, muscle stiffness and tremors.

  • Visual hallucinations – seeing things that are not really there, e.g. people or animals. These often happen repeatedly and are realistic and well-formed.

  • Sleep disturbances – acting out dreams or shouting out while sleeping, which can disrupt sleep and potentially cause injury.

  • Fainting, unsteadiness and falls. 

  • Frontotemporal Dementia 

FTD (also known as Pick’s Disease) is caused by damage to cells in areas of the brain called the frontal and temporal lobes. The frontal lobes regulate our personality, emotions and behaviour, as well as reasoning, planning and decision-making. The temporal lobes are involved in the understanding and production of language. Symptoms may include:

  • Personality changes. This may include a change in how people express their feelings towards others or a lack of understanding of other people’s feelings. They may also show a lack of interest or concern, become disinhibited or behave inappropriately.

  • Lack of personal awareness. People may fail to maintain their normal level of personal hygiene and grooming.

  • Lack of social awareness. This might include making inappropriate jokes, or showing a lack of tact.

  • Changes in food preference, over-eating or over-drinking.

  • Behaviour changes – humour or sexual behaviour may change. People may become more aggressive, develop unusual beliefs, interests or obsessions. Some people become impulsive or easily distracted.

  • Difficulty with simple plans and decisions.

  • Lack of awareness of any changes in personality or behaviour.

  • Decline in language abilities. This might include difficulty getting words out or understanding them. People may repeat commonly used words and phrases, or forget the meaning of words.

  • Difficulty recognising people or knowing what objects are for.

  • Day-to-day memory may be relatively unaffected in the early stages, but problems with attention and concentration could give the impression of memory problems.

  • Movement problems – about one in every eight people with behavioural variant FTD also develops movement problems of motor neurone disease. This can include stiff or twitching muscles, muscle weakness and difficulty swallowing. 

  • Posterior Cortical Atrophy 

PCA is caused by damage to the brain cells at the back of the brain that make sense of what our eyes are seeing.

Alzheimer’s disease is most often the cause of the brain cell damage in PCA. PCA is sometimes called a visual form of Alzheimer’s. However, the early signs of PCA and typical Alzheimer’s can be very different. Alzheimer’s disease usually affects memory first. In PCA the first signs are often problems with vision and perception.

People often develop PCA at an earlier age than typical Alzheimer’s disease, usually between the ages of 50 and 65.

People may have problems with:

  • Things may appear to have an unusual colour, or to move when they are still. A black object can look like a hole. People may still see an image of an object after looking away, or not be able to see more than one object at a time. They may not always be able to see what is right in front of them and may bump into things.

  • Losing the place on a page or missing out lines. This can also affect everyday tasks like putting in a PIN on a cash machine.

  • Crossing roads and using escalators or stairs can become difficult. A person may reach out to grasp an object but miss it.

  • Problems recognising objects or faces, especially when they’re not in plain sight.

    Finding bright light uncomfortable, including glare from shiny surfaces.

  • Problems with dressing and using objects like kitchen utensils and remote controls.

  • Finding spelling or simple calculations hard.

  • Some people become low in mood, irritable or anxious, or may lose interest in things.  

  • Primary Progressive Aphasia 

Primary progressive aphasia (PPA) is a condition caused by damage to parts of the brain that control our personality, emotions, language and behaviour. In most cases, this damage is caused by frontotemporal dementia. Most people who develop PPA will be in their 50s and 60s. This can fall into two different types: 

Semantic Dementia

 People with semantic dementia gradually find it harder to remember the meaning of words. For example, they may:

  • Have trouble using the right word – often saying another word or using a vague term like ‘thing’. This may start with names and other words they don’t use very often. As time passes, people will also struggle with more common words and often ask what words mean.

  • Forget what everyday objects are for or find it hard to recognise them.

  • Talk about things at great length and in a vague or roundabout manner.

  • Find it hard to understand what other people are saying.

  • Have problems reading and spelling.

In the later stages, people tend to say less. Changes in behaviour and personality are more common in semantic dementia than the other types of PPA. For example, people may develop obsessions or a sweet tooth, or act in ways that may seem strange to others.

Progressive Non-Fluent Aphasia 

This condition affects how a person produces speech. For example, they may:

  • Struggle to use the right grammar when speaking or writing letters or emails.

    If you use sentences that are long and complex, someone with this form of dementia may find it hard to understand you. Over time, they may develop other signs including:

  • Stutter or speak more slowly or hesitantly and be hard to understand.

  • Find that words come out in the wrong order or are missed out altogether.

  • Have trouble producing words, although they know what they want to say. Speaking may take a lot of effort and words may not come out right.

  • Problems with reading, writing and spelling.

  • Trouble understanding some words.

  • Changes in behaviour.

  • Trouble with swallowing.

  • Problems making decisions or plans.

Some people show signs similar to Parkinson’s disease such as shaking, being unsteady on their feet or having trouble using their hands.

(information taken from Alzheimer's Research UK website 19 July 2017)

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