Alzheimer's Disease

Alzheimer's disease is a disorder in which there is a steady deterioration of brain function, resulting in progressive loss of memory, recognition, personality, and mental powers. Although Alzheimer's disease may begin as early as age 40, it is most prevalent in the elderly. It accounts for about half of all serious mental impairment in persons over age 65.

Changes in the Brain

In Alzheimer's disease, as in any senile mental disorder, there is atrophy (shrinkage or wasting) of the cerebral cortex (the outer layer of the brain, which is mostly concerned with intellectual and social functioning).

There are also more specific abnormalities, such as the presence of tangles of fibers within the nerve cells and of senile plaques, which are probably deposits of amyloid (a semisolid protein complex seen in many degenerative diseases). These abnormalities are scattered through-out the cortex of a person with Alzheimer's disease; they distinguish the disease from other forms of senility. Because brain biopsy specimens (tissue samples taken from the brain for laboratory examination) are not obtained without very specific reasons and without intention of specific treatment, these abnormalities are usually discovered only after death.

Causes

Theories abound as to the possible causes of Alzheimer's disease. So-called slow viruses (viruses acquired early in life that take many years to do their damage) have been considered, as have environmental factors and damage from previous diseases. Recently, a diminished amount of the enzyme choline acetyltransferase (which is necessary to manufacture the neurotransmitter acetylcholine) has been found in some patients, and theories about replacement of the enzyme or the neurotransmitter are being formulated.

Deficiencies of other neurotransmitters are constantly being discovered. Heredity seems to play some part, since a family history of the disease makes some individuals more likely than others to develop the condition. It is generally agreed that hardening of the arteries is not a cause. Alzheimer's disease does not appear to be contagious, nor is it caused by emotional upsets.

Symptoms

Symptoms vary considerably from one person to another and may occur days or months apart. They begin with small memory lapses, almost always first involving loss of recall for recent events. Such lapses can happen to anyone, but in Alzheimer's disease they grow more serious with time. A person may forget a close relative's name, get lost coming home from the office, forget to turn off the oven, misplace articles, recheck to see if a task was done, or repeatedly ask questions that have already been answered. Eventually, the gaps in memory and the failure to recognize friends and family members will interfere with normal life.

As the disease progresses, the victim of Alzheimer's disease becomes confused, frustrated, and irritable. Although at first the person seems physically unaffected by the disease, as the condition advances, the patient becomes restless, always moving about, and must be watched so that he or she does not wander away or into danger. Endless repetition of unnecessary actions, such as the opening and closing of drawers, is another characteristic symptom of the disease. Some victims of Alzheimer's disease may even become extremely agitated with little or no provocation.

The course of the disease may range from 1 year to as many as 20 years. The disease may eventually result in deterioration of the rest of the nervous system and other parts of the body and in loss of control over bladder and bowels. It may cut life expectancy by contributing to death from another cause, such as pneumonia or heart or kidney failure.

Now that we've covered the causes and symptoms of Alzheimer's, let's look into its diagnosis and treatment in the next section.