Whilst Alzheimer’s disease is the most well known cause of dementia there are many different types of dementia.
Dementia itself is not a disease but a term used to describe a variety of symptoms caused by damage to the brain.
Symptoms associated with dementia include memory loss and changes in thinking, behaviour and personality.
Dementia is usually progressive, meaning symptoms get worse over time.
The most common types of dementia include but are not limited to:
The most common type of dementia is Alzheimer’s disease. Alzheimer’s affects 70% of all people with dementia. In Alzheimer’s disease proteins form leading to ‘plaques’ and ‘tangles’ that damage and destroy brain cells eventually shrinking brain tissue.
The connections between the brain cells are also affected. Initially nerve cells die in the area responsible for memory, thought and language.
A shortage of certain chemicals essential for transmitting messages to and from nerve cells also occurs.
Over time, more damage to the brain occurs causing other symptoms to appear. Eventually a person has problems communicating, difficulty with every day tasks and changes to personality.
Alzheimer’s is a degenerative disease. On average most people with Alzheimer’s disease live 7 to 10 years after first symptoms appear.
Vascular dementia is a form of dementia caused by problems associated with poor circulation of blood to the brain. If our vascular system becomes damaged, brain cells do not receive adequate amounts of blood and the brain will not function properly.
Vascular dementia affects everyone differently. Multi infarct dementia is common and occurs when a series of strokes cause damage to the cortex. This area of the brain is responsible for memory, learning and language. A person can have a series of small strokes that are less obvious and difficult to detect. Symptoms may not be apparent until after several strokes.
Symptoms of vascular dementia include trouble making decisions and solving problems, poor concentration, difficulty with tasks and following steps.
Unlike Alzheimer’s disease, symptoms of vascular dementia usually occur in a stepwise manner where a person appears to stabilise or get better until they have another stroke and their condition deteriorates suddenly.
Dementia with Lewy Bodies
Symptoms of Lewy body dementia (LBD) can greatly resemble those of Parkinson’s disease and Alzheimer’s.
Lewy body dementia refers to both Parkinson’s dementia and dementia with Lewy bodies. Tiny protein deposits called Lewy bodies disrupt nerve cells in the brain and important chemical messengers called dopamine and acetylcholine.
Lewy bodies contribute to progressive diseases like Parkinson’s. Symptoms of Lewy Body dementia can include motor problems such as rigidity, shuffling gait and blank facial expression.
Other symptoms unique to Lewy body dementia include sudden changes in attention and alertness in the day or even minute by minute. Visual hallucinations and sleep disturbance are also common.
Fronto- Temporal Dementia
In fronto-temporal dementia damage to the frontal and/or temporal lobes of the brain occurs affecting not only cognition but mood, social behaviour and attention. Fronto temporal dementia typically affects people in a younger age group than Alzheimer’s with symptoms appearing in the 50s or 60s.
Unlike Alzheimer’s disease, in the early stages memory may not be noticeably affected. Instead a person may exhibit changes in personality including apathy, disinhibition, impulsiveness, loss of empathy or emotion. Others suffer a loss of language skills or difficulty recognising objects.