Mental disorders associated with aging, including Alzheimer's, are far more common in domesticated cats than previously realized, with more than half of all cats over age 15 showing signs of senility, according to a forthcoming Journal of Small Animal Practice paper.

The findings support a growing body of evidence suggesting that most, if not all, mammals, can suffer age-related conditions normally associated with people.

In the case of cats, the main difference is that a 15-year-old individual can be compared to an 85-year-old person. Another recent study found that about half of all octogenarians, too, show signs of dementia.

The behaviors associated with senility in cats range from acting disoriented to changes in their social relationships, to shifting sleep habits, said lead author Danielle Gunn-Moore, head of the Feline Clinic at the University of Edinburgh's Hospital for Small Animals.

They may also include inappropriate vocalizing, forgetting commands, breaking housetraining, pacing, wandering, sluggishness, unusual interest or disinterest in food, and decreased grooming and confusion, such as "forgetting that they have just been fed," said Gunn-Moore.

These behaviors can also be associated with other health conditions, such as thyroid problems and diabetes. To rule out those possibilities, one of Gunn-Moore's team members, Kelly Moffat of Arizona's Mesa Animal Hospital, conducted a study on 154 geriatric cats brought to local vets.

Based on Moffat's results, the researchers concluded that 28 percent of pet cats aged 11 to 14 develop at least one brain-linked behavior problem associated with aging. That percentage then jumps to over 50 for cats 15 years or older.

Together, Moffat, Gunn-Moore and other researchers then focused on the aged cats' brains, using X-rays and post-mortem analysis. They identified thick, gritty plaques on the outside of the cats' brain cells. The plaques contained an Alzheimer-like protein that interferes with brain messaging.

This protein is "crucial to our understanding of the aging process in cats," Gunn-Moore said. "We've known for a long time that cats develop dementia, but this study tells us that the cat's neural system is being compromised in a similar fashion to what we see in human Alzheimer's sufferers."

Rebecca Wood, chief executive of the Alzheimer's Research Trust in England, expressed interest in the findings and said, "Many people will be surprised by the fact that domestic cats can develop a form of Alzheimer's, just like their owners."

Wood added that pets are also living longer "so this type of distressing disease is only going to get more common."

Gunn-Moore believes that good diet, mental stimulation and companionship appear to reduce the risk of dementia in both humans and cats.

"If humans and their cats live in a poor environment with little company and stimulation, they are both at higher risk of dementia," she said. "However, if the owner plays with the cat, it is good for both human and cat."

PLUS

Feline Memories Found to be Fleeting

Aug. 21, 2007 -- From Yahoo News

A new study has measured just low long cats can remember certain kinds of information—10 minutes.

The research was designed primarily to compare cats' working memory of their recent movements with their visual memories, and found that cats remember better with their bodies than their eyes when they have encountered an object placed in their path by say, an annoying owner or experimenter.

When a cat steps over a stray toy or shoe left on the floor on the way to its food dish, it has to coordinate the stepping action of its front legs with its hind legs.

"Animals, including humans, unconsciously keep track of the location of objects relative to the body as they move, and this tracking is largely dependent on signals associated with movement of the body," said researcher Keir Pearson of the University of Alberta in Canada.

Though researchers were aware of this association, they wondered exactly how kitty remembers to bring her hind legs up after her front legs have cleared an obstacle.

To test cats' coordination, the researchers looked at how well they could remember having just stepped over a hurdle. The researchers stopped cats after their front legs had cleared an obstacle, but before their hind legs went over.

They then distracted the animals with food and lowered the obstacle to see how the tabbies would respond. The cats remembered having stepped over the hurdle for at least 10 minutes, bringing their hind legs up to clear the object, even though it wasn't there.

To compare this working memory to the cats' visual memory of the obstacle, the researchers repeated the experiment, this time stopping the cats just before they made their first step over the hurdle.

Turns out the cats weren't so good at remembering what they had seen but not yet done: when the obstacle was removed this time, the cats forgot it had even been there in the first place and continued on their way.

"There's not high-stepping at all," Pearson told LiveScience.

"We've found that the long-lasting memory for guiding hind legs over an obstacle requires stepping of the forelegs over the obstacle," Pearson said. "The main surprise was how short lasting the visual memory on its own was—just a few seconds when animals were stopped before their forelegs stepped over the obstacle."

Research with horses and dogs has shown similar results, Pearson said.

Similar memories may play a role in humans' ability to navigate objects in the dark or remember where they parked their car in the morning.

By actually walking from your car into your office, you solidify the memory of what space your car is in and don't spend half an hour looking for it—well, not usually.