Alzheimer's - the disease of forgetfulness

Old man black/white picture (Gerd Altmann/pixelio.de)
Alzheimer's is a typical age-related disease (Gerd Altmann/pixelio.de)

Alzheimer's is the most common form of dementia and a typical disease of old age. Due to the increasing life expectancy, dementia will be one of the greatest challenges of the future in our society.

About 30 million people worldwide are affected. Experts believe that the number of people suffering from dementia will double by the year 2050.

A growing brain failure

The Latin word dementia translates roughly as "no mind" or "decreasing sense". Dementia is an umbrella term for disease patterns that go along with a gradual loss of memory, thought, orientation, or of the ability to combine thoughts.

In advanced stages, loss of ability to experience, interests or feelings are also common. Often, there is also a change of character. During a later stage, it may result in physical disabilities and the loss of bodily functions.

Dementia is in most cases related to some sort of brain disease, or in other words: Dementia is a progressing failure of the brain.

Alzheimer's is the most common form of dementia

By far the most common form of dementia is Alzheimer's disease, a neurodegenerative disease that is responsible for about 60 percent of all dementias. According to the IDC-10, the international statistical classification of diseases, there are other forms of dementia as vascular dementia, and the secondary dementia.

The vascular dementia can arise due to circulatory disorders, secondary dementia are caused by non-brain-organic underlying diseases such as metabolic disorders, thyroid disorders or infectious diseases.

Old man supporting his front head (Gerd Altmann/pixelio.de)
In dementia, there is a gradual loss of memory and orientation (Gerd Altmann/pixelio.de)

A disease of the elderly

Alzheimer's disease is named after the German neurologist Alois Alzheimer, who in 1907 described the first symptoms of the disease and typical lesions in the brain.

Even though Alzheimer's can also affect persons aged fewer than 50 but it is usually a disease of the elderly. It usually occurs after the age of 65, and the incidence increases with age.

What happens in Alzheimer's

Scientists have found that in the course of Alzheimer's disease, more and more protein cleavage products accumulate in the brain. They affect the transmission of impulses between nerve cells, also called neurons. Over time, the nerve cells die, especially in the regions of the brain that are involved in the development of memory, language and thinking skills.

Why this happens is still not fully understood. It is also unclear whether the deposits are the actual cause or an accompanying symptom of cell death.

Lack of second messenger production

Other symptoms are changes of brain neurotransmitters. In Alzheimer's disease, especially glutamate and acetylcholine are important. In the course of the disease, the production of acetylcholine decreases more and more. The worsening neurotransmitter deficiency shows by impairment of the ability to memorise, concentrate as well as by attention difficulties.

Science believes that Alzheimer's disease occurs when several damages are coming together. Moreover, there is probably a predisposition of the patients for this disease. Approximately five to ten percent of the patients have had Alzheimer’s in their families before.

Wood fading in the mist (Gabriele P./pixelio.de.)
Alzheimer's: When the memories fade - and eventually completely disappear (Gabriele P./pixelio.de.)

Alzheimer's runs in three phases:

In the initial stage, some first mental deficiencies are identified. Affected people are forgetful, especially on things that happened only recently. It causes disorientation and confusion. The uncertainty and frustration about what happens to them can lead from mood swings to depression.

In the second stage and with the loss of intellectual abilities, self-dependent common tasks are already difficult. The independence diminishes. This can lead to problems with household tasks or getting dressed as well as to neglected hygiene. Forgetfulness increases, the disorientation is greater. There may be language and cognitive disorders.

In the third stage there is a loss of daily living; patients are completely dependent on aid. The memory is decreases and the long-term memory is affected now too. The patients hardly perceive themselves and their surroundings. Even organic functions are increasingly impaired: the control of the bowel and bladder fails, the day-night cycle is disturbed, it can also cause muscle spasms, difficulty swallowing, or seizures.

Alzheimer's stages are accompanied by frequent psychological symptoms such as depression, anxiety and hallucinations, as a result of impaired brain function.

Text: Patrick Gunti - 12/2011
Translation: MPL
Pictures: pixelio.de