Alzheimer's is the most common form of dementia, a disease which affects a person's ability to remember things (particularly newly learned information) and can go on to damage their intellectual abilities enough to make daily life difficult without assistance.
Alzheimer's is not a normal part of the aging process, and it's a progressive disease where symptoms develop over a number of years starting with mild memory loss. Later on patients can lose their ability to converse or respond to things happening around them. There is no cure for Alzheimer's, although some treatment exists to reduce the symptoms and the rate of decline.
It's important to keep an Alzheimer's patient alert and active to help relieve boredom and restlessness and provide stimulation for them. Children's activities such as simple word games, mazes and spot the difference puzzles are ideal for this, although you must be careful not to give activities that look too childish, particularly to those patients who have recently acquired Alzheimer's.