Dementia is a general term for a decline in mental ability due to disease or injury. Dementia affects memory, thinking and judgment. A person with dementia may have trouble remembering things, trouble finding the right words, and may show mood or behaviour changes.
Although any decline in brain function is often referred to as dementia, it’s actually an umbrella term for a number of neurological conditions.
Dementia was relatively rare before the 20th century as the life expectancy was a lot shorter than today. It wasn’t until the mid-1970s that dementia was identified as what we know it to be today.
Now, we know dementia is a symptom of disease and not a normal part of ageing.
Read: New tool could help detect early-onset dementia
There are more 100 diseases that may cause dementia. The most common causes of dementia include Alzheimer’s disease, vascular dementia and dementia with Lewy bodies.
Here are the symptoms and warning signs of the four most common types of dementia.
Alzheimer’s disease
Alzheimer’s disease is the most common cause of dementia among older adults.
The disease is named after Dr Alois Alzheimer who, in 1906, noticed changes in the brain tissue of a woman who died of an unusual mental illness. Her symptoms included memory loss, language problems, and unpredictable behaviour for the five years before her death.
After she died, Dr Alzheimer examined her brain and found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibres (now called neurofibrillary, or tau, tangles).
Alzheimer’s disease signs and symptoms include:
- memory problems, such as regularly forgetting recent events, names and faces
- asking questions repetitively
- increasing difficulties with tasks and activities that require organisation and planning
- becoming confused in unfamiliar environments
- difficulty finding the right words
- difficulty with numbers and/or handling money in shops
- becoming more withdrawn or anxious.
Vascular dementia
Vascular dementia is the second most common type of dementia and symptoms can vary drastically depending on the person, the cause and the areas of the brain that are affected.
Symptoms may be most obvious when they happen soon after a major stroke and swiftly worsen. But they can also take time to develop, appearing over several months or even years.
The symptoms can be similar to Alzheimer’s disease, but memory loss in the early stages of vascular dementia is typically less pronounced.
Vascular dementia signs and symptoms include:
- confusion
- trouble paying attention and concentrating
- reduced ability to organise thoughts or actions
- decline in ability to analyse a situation, develop an effective plan and communicate that plan to others
- slowed thinking
- difficulty with organisation
- difficulty deciding what to do next
- problems with memory
- restlessness and agitation
- unsteady gait
- sudden or frequent urge to urinate or inability to control passing urine
- depression or apathy.
Read: Dementia risk affected by postcode and background
Dementia with Lewy bodies
Also called Lewy body disease, this type of dementia is diagnosed by taking a careful history of the pattern of symptoms displayed.
A brain scan may reveal brain degeneration, but the Lewy bodies can only be identified by examination of brain tissue after death.
Lewy body disease is similar to Alzheimer’s disease in many ways, and in the past, it has sometimes been difficult to distinguish the two.
Dementia with Lewy bodies signs and symptoms include:
- difficulty with concentration and attention
- fluctuating levels of confusion
- delusions and/or depression
- difficulties judging distances, often resulting in falls.
There are also three cardinal symptoms, two of which must be present in order to make the diagnosis:
- visual hallucinations
- Parkinsonism (tremors and stiffness similar to that seen in Parkinson’s disease)
- wide fluctuation in mental state so that the person may be lucid and clear at one time and confused, disoriented and bewildered at other times.
Frontotemporal dementia
Any brain disorder that affects the frontal and temporal lobes falls under the umbrella term of frontotemporal dementia.
These areas of the brain are generally associated with personality, behaviour and language. And symptoms vary depending on which part of the brain is affected.
Frontotemporal dementia can be misdiagnosed as a psychiatric problem or as Alzheimer’s disease. But the onset of frontotemporal dementia tends to occur at a younger age than with Alzheimer’s disease.
This dementia often begins between the ages of 45 and 65.
Read: Everyday behaviours that could be signs of dementia
Frontotemporal dementia signs and symptoms include:
- increasingly inappropriate social behaviour
- loss of empathy and other interpersonal skills, such as having sensitivity to another’s feelings
- lack of judgment
- loss of inhibition
- lack of interest (apathy), which can be mistaken for depression
- repetitive compulsive behaviour, such as tapping, clapping or smacking lips
- changes in eating habits, usually overeating or developing a preference for sweets and carbohydrates
- having trouble finding the right word to use in speech or naming objects
- making mistakes in sentence construction
- muscle spasms or twitches
- poor coordination
- difficulty swallowing
- muscle weakness.
There are a broad range of symptoms in even the four most common types of dementia so reaching a diagnosis can be difficult. If you have any concerns, reach out to your medical practitioner.
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Disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.