LONDON (Reuters) -- Ageing cats can suffer from a feline form of Alzheimer's disease, just like their owners.

But a healthy diet, mental stimulation and companionship can reduce the risk of the debilitating illness, scientists said on Wednesday.

"We now know that our old cats, like old people, are at risk of developing these conditions," said Dr. Danielle Gunn-Moore, of the University of Edinburgh's Royal School of Veterinary Studies.

Alzheimer's disease is the leading cause of dementia in the elderly, afflicting about 12 million people worldwide. Abnormal clumps of proteins called amyloid plaques and tangles develop in patients which inhibit messages being processed by the brain.

Gunn-Moore started her research with collaborators in Scotland and California after noticing signs of senility in her own cat when he was 8 years old.

The scientists found abnormal proteins similar to those in humans in the brains of diseased cats during routine autopsies by using special tests.

Use it or lose it

Gunn-Moore suspects other animals, including dogs, are also susceptible to Alzheimer's and other types of dementia. In Britain alone there are up to 9 million pet cats and about a third of them are elderly. "I suspect that a lot of animals simply never get that old," said Gunn-Moore. "If they are in the wild it would be very unusual for an animal to still be alive to the point it could develop Alzheimer's. But we are keeping our pets cats alive longer and longer."

Cats age much quicker than humans and could provide vital information about the ageing process, the development of dementia and potential treatments for animals and humans.

Most cats are considered seniors by the time they reach seven years old and geriatric by 12. Gunn-Moore, a cat expert, routinely sees cats in their 20s. The oldest cat to her knowledge lived to 32.

"The shorter lifespan of a cat, compared to humans, allows researchers to more rapidly assess the effects of diet, high blood pressure, and prescribed drugs on the course of the disease," she told Reuters.

Early signs of feline dementia include behavioural changes, loss of litter-box training and night crying due to alterations in sleep cycles.

Just as in humans, the "use it or lose it" principle applies.

Lack of environmental and mental stimulation and interaction can be important factors that may contribute to the illness.

"There is so much more we can do for our geriatric felines," said Gunn-Moore, who reported the findings in the Journal of Feline Medicine.

"We want to make cats interact and making them interact with us is great because it is good for the relationship between cats and their owners," she added.