If you think old Sylvester was demented, you may be right.

Cause an international team found that aging cats can suffer from a feline form of dementia, similar to Alzheimer's disease in humans, the most common form of dementia in humans.

Researchers have discovered in cats a key protein which can build up in the brain neurons and cause mental deterioration. In humans with Alzheimer's disease, this protein creates 'tangles' inside the neurons which inhibit the information to be processed by the brain.

The presence of this protein in cats may be a proof that they too can develop this type of disease. It has long been known that cats can suffer from dementia. Previous research identified thick, gritty plaques on the outside of the brain cells of old animals, similar to those found in humans.

The shorter lifespan of the cat may make it easier for scientists to uncover how the condition develops, by carrying out post-mortem examination of cats which have succumbed naturally to the disease. This may eventually help scientists to come up with possible treatments. "This newly discovered protein is crucial to our understanding of the aging process in cats" said Dr Danielle Gunn-Moore, of Edinburgh University.

"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 that we see in human Alzheimer's sufferers. The gritty plaques had only hinted that might be the case - now we know."

"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."

"However, we also need to understand more about our geriatric cats for their own benefit, so we can slow down the degeneration the disease brings and keep them as happy cats for as long as possible."

"As with humans, the life expectancy of cats is increasing and with this longer life runs the greater chance of developing dementia. Recent studies suggest that 28% of pet cats aged 11-14 years develop at least one old-age related behavior problem and this increases to more than 50% for cats over the age of 15."

It seems that good diet, mental stimulation and companionship can 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. However, if the owner plays with the cat, it is good for both human and cat. A good diet enriched with antioxidants is also helpful in warding off dementia, so a cat owner sharing healthy meals like chicken and fish with their pet will benefit them both." added Gunn Moore. "We are now currently trying to develop new and novel treatments which will be able to help both cats and humans".