Inside track on how Alzheimer’s changes the brain
IN THIS insightful series, first published in Good Health in March 2015, the Mail serialised a book by
Dr Keith Souter, a retired GP and fellow of the Royal College of General Practitioners, offering readers indispensable advice on how to understand and deal with dementia, which is still of huge help to the 64,000 people estimated to be living with dementia in Ireland today, and those who help care for them.
March 23, 2015
ACCORDING to the Alzheimer’s Society, there are already more than 64,000 people with dementia in Ireland and that number is set to double over the next 35 years.
Fears about becoming one of them has led to a surge of people turning up at dementia clinics.
Figures published earlier this month show there’s been a fourfold rise in the number of patients seeking help at these specialist centres.
They’re anxious about their forgetfulness and unsure of what it means.
So how can you tell if you — or someone close to you — is just a bit forgetful or in the early stages of dementia? And what can you do to cut your risk of developing the disease in the first place?
THERE ARE 200 TYPES OF DEMENTIA
DEMENTIA is not a single disease, but is an umbrella term for a group of conditions that damage the brain.
In fact, there are more than 200 types of dementia. Alzheimer’s disease, which accounts for 60 to 70 per cent of cases, is the most common form. One of the main features of Alzheimer’s — and all forms of dementia — is that the brain shrinks.
Initially, this affects the hippocampus, the area of the brain associated with memory.
There is also an overproduction of tau, the protein made by nerve cells in the brain to maintain their shape. The excess tau forms ‘tangles’, which affect the normal connections between neighbouring cells.
In addition, there is a drop in acetylcholine, a chemical messenger vital for memory.
Structures called amyloid plaques, clumps of a protein produced by nerve cells, are also found in the brains of those with Alzheimer’s.
The next most common form of the condition is vascular dementia, which accounts for 20 per cent of cases and is linked to lifestyle — it’s a bit like heart disease of the brain. It occurs following a stroke or when the blood vessels supplying the brain become furred up or blocked. If blood supply is cut off to a part of the brain, the brain cells die off within just six minutes. With this, as with some other forms, there may be no memory loss at all — patients may, for example, have problems finding the right words to express themselves or have balance problems, making them prone to falls.
Some people suffer from ‘mixed pattern’ dementia, a combination of Alzheimer’s and vascular dementia.
Whereas all forms of dementia involve some form of damage to the brain, what differentiates them is where that damage occurs.
DO WE ALL GET IT EVENTUALLY?
DEMENTIA is not a normal part of ageing. It’s true that, as we age, even healthy brains shrink from the age of 50.
Between the ages of 50 to 65, the average brain may lose 4oz or 5oz in weight.
The levels of chemical messengers, called neurotransmitters, also drop and the brain’s ability to absorb glucose, which it needs to function, is reduced.
This is why some notice a slowing down of their mental functions or they can’t do things as quickly as they used to.
This can lead to the ‘tip of the tongue’ problem when you can’t remember a word or name.
This is incredibly common and in most cases does not mean that person is actually developing dementia.
In dementia, the brain cells die off faster than they normally would and there will be greater shrinkage of the brain. This leads to a far more extreme deterioration than simple ageing.
Why some people go on to develop dementia while many others don’t is not known for sure. Lifestyle factors such as having high blood pressure or raised cholesterol increase the risk, as does being a woman — two-thirds of people with dementia are female.
Genetics can play a part, but only in a small percentage of cases.
ADAPTED from Your Guide To Understanding And Dealing With Dementia by Dr Keith Souter, published by Summersdale, €14.60, amazon.co.uk.