As many pet owners will attest, just being around an animal can have a soothing effect. This is the idea behind pet therapy for people with Alzheimer's disease, who are at particular risk for anxiety and depression. In this kind of therapy, the pet's human companion introduces the animal -- whether it's a dog, cat, guinea pig, or other domestic pet -- to the person with Alzheimer's and helps the interaction go smoothly and safely. These visits generally occur in nursing homes, adult day centers, and hospitals, but of course the idea can be used in the home as well.

The benefits of pet therapy include lowering anxiety and stress, encouraging communication, improving mood, and lowering blood pressure. People with Alzheimer's may feel especially comfortable with a pet because it lets them interact nonverbally.

• What you can do: The person you're caring for probably isn't capable of looking after a pet, so it's not a good idea to run out and buy her a kitten unless someone is available around the clock to provide its care. But even pet therapy that doesn't involve direct contact with pets -- bird-watching and looking at an aquarium -- seems to have positive effects. Research funded by the Pet Care Trust, a nonprofit foundation, and conducted by Purdue University, found that Alzheimer's patients provided with aquariums gained weight (indicating better nutritional intake -- people with Alzheimer's often have trouble eating adequately) and showed less aggression. Try setting up an aquarium or bird feeders outside a favorite window view.