The examination showed changes Alzheimer had never witnessed before. Parts of the brain showed tangling and other parts showed clumping of brain matter. Later research showed more "younger" people who had died of dementia who displayed the same brain abnormalities. This came to be known as Alzheimer's disease.

It was later found that this type of dementia occurred far more often in older people, with their brains showing the same abnormalities at microscopic level.

However, at this time, Alzheimer's disease was a diagnosis only applied to younger sufferers, since these formed the basis of Alois Alzheimer's research. Older sufferers were labeled with pre-senile dementia or senile dementia of the Alzheimer type (SDAT).

Nowadays, with dementia in younger people being quite uncommon, it is usual for the term Alzheimer's disease to describe this entire group, right across the age range.

'Alzheimer's disease' is a deceptively simple label for a complicated set of symptoms which are hard to describe in their fullness without direct personal experience of such in another. A suitably evocative description is "A living death", while more prosaic medical terminology cites "the slow onset of memory loss with a gradual progression to a loss of judgement and changes in behavior and temperament."

The Royal College of Physicians describes Alzheimer's disease in more detail, defining dementia as fundamentally "the global impairment of higher functions", listing its impact on memory, daily problem-solving ability, the performance of learned perceptuo-motor skills (such as washing, dressing, and eating), appropriate use of social skills, and control of the emotional reactions, all of which occur under the influence of an increasingly clouded consciousness which is sadly typical of Alzheimer's.

Memory loss is of course the most obvious feature of Alzheimer's disease, but early on it can pass undetected as sufferers often manage to cover it up. The most recent memories go first, the distant past or long-term memory holding out until the disease has become quite advanced.

The short-term memory covers recent events, such as those taking place in the last hours or days, even weeks, and it is this which Alzheimer's sufferers have real problems with, and whose failure can signify the onset of Alzheimer's disease.

Because memory loss is central to Alzheimer's disease and can easily be tested for, memory tests are an important diagnostic tool used to assess Alzheimer's sufferers.

One formerly common test was to ask suspected Alzheimer's sufferers a list of questions which probed both their long and short-term memory.

Typical questions included: How old are you, what is your date of birth, what day is it today, what month is it, what year is it, when was the First World War, what is the name of the Prime Minister, where are you now, count back from 20 to 1, and finally the sufferer would be given an address and asked to repeat it back 5 mnutes later.

If the suspected Alzheimer's sufferer is co-operative, having been asked the questions in a respectful and unintrusive way, this is a relatively easy and inexpensive test to carry out, and which can yield useful pointers as to which parts of the memory may be problematic. Not only will long or short-term memory problems (or both) show up, but also potential orientation issues.

However, a low score by itself doesn't prove either dementia or Alzheimer's disease, as not everyone will know all the answers regardless of the state of their memory. The test is simply a guide to show that there may be a problem that needs further investigation.

The above is an overview of aspects of the very complex and involved medical condition known as Alzheimer's disease.