There ARE 5 different types of dementia
The five most common forms of dementia are:
- Alzheimer disease: the most common dementia diagnosis among older adults. It is caused by changes in the brain, including abnormal buildups of proteins, known as amyloid plaques and tau tangles.
- Frontotemporal dementia: a rare form of dementia that tends to occur in people younger than 60. It is associated with abnormal amounts or forms of the proteins tau and TDP-43.
Frontotemporal dementia is caused when nerve cells in the frontal and/or temporal lobes of the brain die and the pathways that connect them change. There is also some loss of important chemical messengers. Over time, the brain tissue in the frontal and temporal lobes shrinks.
This damage to the brain causes the typical symptoms of frontotemporal dementia, which include changes in personality and behaviour, and difficulties with language.
As frontotemporal dementia is a less common form of dementia, many people (including some health professionals) may not have heard of it.
In frontotemporal dementia, a variety of symptoms are caused by damage to different areas of the frontal and temporal lobes. Based on these symptoms and the lobes that are affected, a person may have one of three types of frontotemporal dementia:
- behavioural variant frontotemporal dementia
- progressive non-fluent aphasia
- semantic dementia.
As with most forms of dementia, the initial symptoms can be very subtle, but they slowly get worse as the disease progresses over several years.
Behavioural variant frontotemporal dementia
This form is diagnosed in about two thirds of people with frontotemporal dementia. During the early stages, changes are seen in the person’s personality and behaviour.
A person with behavioural variant frontotemporal dementia may:
- lose their inhibitions – behave in socially inappropriate ways and act in an impulsive or rash manner; this could include making tactless or inappropriate comments about someone’s appearance
- lose interest in people and things – lose motivation but (unlike someone with depression) they are not sad
- lose sympathy or empathy – become less responsive to the needs of others and show less social interest or personal warmth; this can make the person appear selfish and unfeeling
- show repetitive, compulsive or ritualised behaviours – this can include repeated use of phrases or gestures, hoarding and obsessions with timekeeping
- crave sweet or fatty foods, lose table etiquette, or binge on ‘junk’ foods, alcohol or cigarettes.
It is common for a person with behavioural variant frontotemporal dementia to struggle with planning and organising or making decisions. These difficulties may first appear at work or with managing finances
- Lewy body dementia: a form of dementia caused by abnormal deposits of the protein alpha-synuclein, called Lewy bodies.
Lewy body dementia signs and symptoms can include:
- Visual hallucinations. Hallucinations — seeing things that aren’t there — might be one of the first symptoms, and they often recur. People with Lewy body dementia might hallucinate shapes, animals or people. Sound (auditory), smell (olfactory) or touch (tactile) hallucinations are possible.
- Movement disorders. Signs of Parkinson’s disease (parkinsonian signs), such as slowed movement, rigid muscles, tremor or a shuffling walk can occur. This can lead to falling.
- Poor regulation of body functions (autonomic nervous system). Blood pressure, pulse, sweating and the digestive process are regulated by a part of the nervous system that is often affected by Lewy body dementia. This can result in sudden drops in blood pressure upon standing (orthostatic hypotension), dizziness, falls, loss of bladder control (urinary incontinence) and bowel issues such as constipation.
- Cognitive problems. You might have thinking (cognitive) problems similar to those of Alzheimer’s disease, such as confusion, poor attention, visual-spatial problems and memory loss.
- Sleep difficulties. You might have rapid eye movement (REM) sleep behavior disorder, which can cause you to physically act out your dreams while you’re asleep. This might involve behavior such as punching, kicking, yelling and screaming while sleeping.
- Fluctuating attention. Episodes of drowsiness, long periods of staring into space, long naps during the day or disorganized speech are possible.
- Depression. You might develop depression.
- Apathy. You might lose motivation.
Lewy body dementia is characterized by the abnormal buildup of proteins into masses known as Lewy bodies. This protein is also associated with Parkinson’s disease. People who have Lewy bodies in their brains also have the plaques and tangles associated with Alzheimer’s disease.
A few factors seem to increase the risk of developing Lewy body dementia, including:
- Age. People older than 60 are at greater risk.
- Sex. Lewy body dementia affects more men than women.
- Family history. Those who have a family member with Lewy body dementia or Parkinson’s disease are at greater risk.
- Vascular dementia: a form of dementia caused by conditions that damage blood vessels in the brain or interrupt the flow of blood and oxygen to the brain.
There are a number of early signs of vascular dementia according to Helen Green, Admiral Nurse at Dementia UK. She explained vascular dementia is the second most common form of dementia and it is caused by disruption of the blood supply to the brain preventing oxygen reaching the cells of the brain. She said memory problems may not be an issue initially, and there are other signs to look out for.
“If disruption occurs and this is unable to happen, brain cells will die. The death of brain cells can lead to a variety of problems with cognition such as increased confusion and disorientation, communication, thinking and reasoning.
“This can occur gradually due to disease, or come on suddenly, for example with a stroke. For some people, the cause of vascular dementia may be blocked arteries (atherosclerosis) which can be caused by an unhealthy diet.
“For others, it may be caused by bursting of blood vessels in the brain (haemorrhage) such as after a traumatic injury.”
- Mixed dementia: a combination of two or more types of dementia.
Researchers have also identified many other conditions that can cause dementia or dementia-like symptoms. These conditions include:
- Argyrophilic grain disease: a common, late-onset degenerative disease
- Creutzfeldt-Jakob disease: a rare brain disorder
- Huntington’s disease: an inherited, progressive brain disease
- Chronic traumatic encephalopathy: caused by repeated traumatic brain injury
- HIV-associated dementia: a rare disease that occurs when the HIV virus spreads to the brain
Other conditions that cause dementia-like symptoms can be halted or even reversed with treatment. For example, normal pressure hydrocephalus, an abnormal buildup of cerebrospinal fluid in the brain, often resolves with treatment. In addition, medical conditions such as stress, anxiety, depression, and delirium can cause serious memory problems that resemble dementia, as can side effects of certain medicines.