As people age, their brain and nervous system go through natural changes. The brain and spinal cord lose nerve cells and weight. Nerve cells may begin to transmit messages more slowly than in the past. Waste products can collect in the brain tissue as nerve cells break down, causing abnormal structures called plaques and tangles to form. A fatty brown pigment (lipofuscin) can also build up in nerve tissue.

As nerves break down, they can affect the senses. You might have reduced or lost reflexes, leading to problems with movement and safety.

Some slight slowing of thought, memory, and thinking seems to be a normal part of aging. Although these changes are natural, many people have misconceptions about the type and extent of these changes. A common myth is that all elderly people become senile. Or, many people blame increased confusion on "getting old" when it may really be caused by an illness.

These changes are not the same in everyone. Some people have many physical changes in their nerves and brain tissue, others have few changes. Some people will have atrophy and plaques, some will have plaques and tangles, and some will have other changes.

Furthermore, these changes are not always clearly related to their effects on your ability to think. For example, plaques and tangles are associated with Alzheimer's disease, but some people with the most severe symptoms have fewer plaques and tangles than those who have mild or moderate symptoms.

NERVOUS SYSTEM PROBLEMS IN THE ELDERLY

Delirium, dementia, and severe memory loss are NOT normal processes of aging. They can be caused by degenerative brain disorders such as Alzheimer's disease.

Illnesses that are not related to the brain can also cause changes in thinking and behavior. For example, almost any infection can cause an older person to become severely confused. Poorly controlled blood sugar (glucose) levels in people with diabetes is another common cause of temporary difficulties with thinking and behavior. Rising and falling glucose levels can interfere with thought.

Discuss any significant changes in memory, thought, or ability to perform a task with your health care provider, especially if these symptoms occur suddenly or along with other symptoms. A change in thinking, memory, or behavior is important if it is different from your normal patterns or it affects your lifestyle.

PREVENTION

There is some evidence that both physical and mental exercise can help maintain thinking abilities. Reading, doing crossword puzzles, and engaging in stimulating conversations -- as well as ordinary physical exercise -- may all help keep your brain as sharp as possible. Such strategies have not been proven, however.

See also:

• Aging changes in organs, tissues, and cells
• Aging changes in the senses