Sue Greenwell, age 12, of Dekaib, I11., for her question:

WHAT CAUSES SENILITY?

    Senility is one of the last steps in the process called aging. Often it brings feebleness and deterioration of the body and mind. This state is essentially normal and is caused by organ fatigue after many years of life.

Hardening of the blood vessels is one of the major changes in senility. The hardening narrows the blood vessels, the blood supply diminishes and many organs cannot work as they should.

Senility occurs later in some persons than in others. but those who become senile usually reach this stage after about 65 or 70 years of age. They first go through senescence, a period when the body ages without becoming weak.

Among the more common symptoms of senile brain disease are forgetfulness, confusion, weakness and poor judgment.

Old people tend to deteriorate more rapidly when they are ignored and allowed to sit around doing nothing: When they are forced to assume responsibility and are offered chances to socialize, their mental functions frequently remain fairly normal.