Alzheimer disease is a progressive disease of the brain, which leads to loss of nerve cells. This is the cause of the gradual decline in mental and everyday practical abilities.
The first signs of the disease are usually forgetfulness and difficulties in keeping track of time. Increasingly often, things are being misplaced, appointments are missed and problems arise in coping with everyday life. It may be difficult to tie the shoelaces or finding the right words for certain things, or friends, family or acquaintances are suddenly no longer recognized. Anyone my develop Alzheimer disease. Its precise cause, however, still remains a mystery to medical research. Although we now know several risk factors, it appears that there is not one single cause that explains everything. Alzheimer disease is not a normal consequence of getting older. Nevertheless, the risk of developing dementia increases with age. One in twenty people between the ages of 70 and 74 is affected and almost one in every three over the age of 90. In 2009, about 35 million people world-wide have been living with the diagnosis. Since the percentage of older people is constantly increasing, experts reckon there will be a drastic rise in the disease. It is assumed that the number of Alzheimer patients will roughly double every 20 years. This means that by 2030, some 66 million people would be affected
The loss of everyday competence. Not only memory, but also many abilities important for everyday life are affected by Alzheimer’s.
“Daily living skills” means being able to manage the trivial things of life independently: shopping, cleaning, cooking, grooming, socializing etc. Tasks that come naturally to healthy people, but which become an increasing hurdle for those with Alzheimer’s disease. We can divide daily living skills into four areas:
- Cognitive abilities
- Basic everyday activities
- Social behavior
The disease progression in Alzheimer patients leads to a gradual deterioration in all four areas. But the course of the symptoms is highly individual. So the extent to which the individual areas are affected is different for every patient.
What happens in the brain?
The human brain is a highly complex organ. In a healthy person, 100 billion nerve cells ensure that every moment countless impressions and bits of information are recorded, processed or ignored.
The nerve cells in the brain are immensely active: signals are constantly being sent and received by nerve cells. One can think of it as the nerve cells permanently “talking” to each other to be continuously updated on what happens in and around the body.
Healthy nerve cells require neurotransmitters.
Neurotransmitters play an important role in the exchange of signals between nerve cells. To put it simply, these transmitter molecules are like keys - they activate only the receptors where they fit in the ‘lock’. 70% of all nerve cells exchange information via glutamate receptor activity using the transmitter “glutamate”. Other nerve cells have cholinergic receptors utilizing the transmitter called acetylcholine. There are many other neurotransmitters, but these are the two most important when it comes to dementia.
Alzheimer disease – the exchange of signals between nerve cells is impaired.
A small protein molecule called β-amyloid is produced in excessive amounts in the brain of Alzheimer patients. β-amyloid is deposited between the nerve cells like a kind of waste. These deposits (amyloid plaques) are believed to disturb the neuronal network in the brain. Another protein (τ-protein) constituting the neurons’ internal transport system (microtubules) becomes hyper-phosphorylated and coils up inside the cell and may be seen as a neurofibrillary tangle, which is lethal to the cell. Over time these pathologies increase and the exchange of signals between nerve cells becomes increasingly impaired.