Cognitive Growth and Decline
Unfortunately, certain mental functioning aspects do decline with age, such as memory, reasoning, and complex problem solving. This isn't to say that these abilities necessarily disappear; they sometimes just take a little longer to process. For instance, you may notice that it takes elderly people longer to think of names or other information than it does for younger people. The information may still be there, but the speed of cognitive processing has slowed, making it difficult at times to retrieve that information.
The ability to utilize deductive reasoning and/or to use new information in problem solving also declines with age. While it may seem as if a large portion of your mental processes is vulnerable to deterioration, it really isn't as bad as it sounds. It may be annoying, but this doesn't mean that an elderly person becomes incapable of taking care of herself.
Many people assume that to get older means to get depressed and lack interest in activities that used to be stimulating. This is simply not true. While depression can certainly affect the elderly, the two do not go hand in hand. There are many elderly people living their lives the happiest they've ever been.
Not all aspects of mental functioning decline with age. Some skills that you have consistently used throughout the course of your lifetime, such as the ability to define words or solve mathematical equations, tends to remain stable and retrievable throughout the later years. The best part is that it is even possible that these skills will improve! Of course, this depends on the education you've received and the amount of experience you've had with the particular skill.
Treatable Cognitive Conditions
Thankfully, researchers have been able to dispel some of the preconceived notions of senility and other conditions formerly associated with old age. Not only are some of these conditions not brought on by the aging process, but they are also treatable, ultimately improving the quality of life for the elderly.
For instance, senility was once thought to be just an accepted by-product of old age. However, recent studies have shown that many cases of senility aren't senility at all, but rather side effects of certain types of medication or combinations of medications. As you learned earlier, exercise and proper diet can do a lot for a person's energy levels, strength, and stamina. Therefore, whereas frailty was once considered an inevitable effect of aging, it is now known that frailty and weakness do not have to be accepted. Doctors can help set their patients on exercise and diet regimens that will help them to live more active lives.
Alzheimer's Disease
Alzheimer's disease often crosses the minds of those who worry about aging, and with good reason. Alzheimer's disease is a degenerative disease that results in the loss of brain cells. Those with Alzheimer's suffer a variety of symptoms, including memory loss, disorientation, problems with reasoning, personality changes, agitation, anxiety, delusions, hallucinations, and an inability to perform routine tasks. Such a disease is incredibly frightening both for the sufferer and for his family.
According to the Alzheimer's Association, approximately 10 percent of people over the age of 65 have developed Alzheimer's disease. Approximately 50 percent of people over the age of 85 have the disease. Obviously, age does play a role in a person's risk of developing the disease.
The duration of the disease can last anywhere from three to 20 years. While there is no cure as of yet, there are several drugs being employed to slow down the degenerative process, thus adding several years of independence to the patient's life. Eventually, however, the disease progresses to the point where the patient will require 24-hour care and could even possibly lead to death due to the loss of brain function.
No one knows exactly what causes Alzheimer's disease; however, it is pretty commonly known that age plays a role in its development. This isn't to say that everyone who reaches age 65 and beyond will develop the disease. Of course, some people are more susceptible than others, especially those with a family history of the disease.

