The vast majority of older people do not have organic brain disorders. The prevalence of dementia in the aged has been estimated at approximately 2 to 5 percent of non-institutionalized adults, and only 20 percent among individuals over eighty. Not long ago "hardening of the arteries" was incorrectly regarded as the primary cause of dementia; presently, "Dementia of the Alzheimer type is believed to account for more cases of dementia than any other single disease" (Davison/Neale, 1986). Much disorientation among older people can be attributed to depression (older people suffer losses that include: health, income, property, power, and life-long friends), or the side effects of medications; these types of disorientation are reversible and can occur in all age groups.
In the minority of older adults, where permanent dementia does occur, there is sometimes an alarming change in language and behavior. This can be confusing and upsetting for family members who knew a very different grandfather or grandmother. For example, one lady that I used to visit at a nursing home would greet me eagerly with a stream of obscenity, then proceed to follow it up with sexual advances! She had been a very devout person and a Sunday school teacher. What happened?
Perhaps it would help to view the brain as having "neurological gates." When brain damage affects these gates, they are no longer able to control and contain the flow of information stored in the various corrals. In addition, with the arrival of better diagnostic methods and the common use of sophisticated equipment, more brain cancer is being identified than ever before. Of course, brain cancer ruins memory, reasoning processes, and emotional stability. It is not only difficult for the person who has it; but, also for family members who are wondering, "who is this person?" Brain damage resulting from accidents with young people or disease with older people may result in the loss of ability to inhibit impulses or control emotions. In such cases the person may begin to use words they abhor, or become angry with people they love. They may act in uncommon ways. The problem is not spiritual in origin, but physical. Understanding is called for in both cases. And yes, as a result, your loved one has changed --it's not their fault, and it's not your fault. Their calculator is broke; and they're just not able to come up with the right numbers any more.