Cats develop dementia just like humans, study finds - here are the key signs to look out for

It's a debilitating syndrome that cruelly affects different aspects of cognitive functioning – such as thinking, remembering, and reasoning.

But dementia, which affects about 57 million people worldwide, is not just specific to humans. 

Alzheimer's disease, the most common form of dementia, affects cats in the same way it affects humans, a new study reveals.

Scientists at the University of Edinburgh say cats showing dementia symptoms – such as confusion, sleep disruption and more meowing – have brain changes similar to those in people with Alzheimer's. 

Studying feline dementia has the potential to help develop human treatments because the condition between the two species is so similar.

And in turn, these treatments could be administered to cats with dementia as well.  

'Dementia is a devastating disease – whether it affects humans, cats, or dogs,' said Dr Robert McGeachan, study lead at the University of Edinburgh. 

'Our findings highlight the striking similarities between feline dementia and Alzheimer's disease in people.'

Around 50 million people around the world live with Alzheimer's disease – which accounts for between 50 per cent and 70 per cent of dementia cases.

Although the exact cause of Alzheimer's disease is not yet fully understood, it is thought to be caused by the abnormal build–up of proteins in and around brain cells.

In cats, symptoms of dementia include increased meowing, confusion, spatial disorientation, poor grooming habits and disrupted sleep , such as sleeping more than usual or being awake at night. 

Other key signs include forgetting that they have just been fed, going to the bathroom outside the litterbox and staring off into space while looking at a wall or corner. 

For their study, the University of Edinburgh scientists carried out a post–mortem brain examination on the brains of 25 cats of different ages after they had passed away, including those with signs of dementia.

In the brains of felines with dementia, there was a build–up was found of amyloid–beta, a toxic protein and one of the defining features of Alzheimer's disease, they found.

The dangerous protein clumps together in and around brain cells, first forming small clusters, before eventually accumulating into bulky 'plaques'. 

These plaques build up between nerve cells in the brain and disrupt communication between cells, affecting memory, thinking and daily functioning. 

Powerful microscopy images also revealed a build–up of amyloid–beta within the synapses – the connections between brain cells – of cats with dementia, as well as older cats. 

'We already knew that a toxic protein called amyloid–beta, also seen in human Alzheimer's, builds up in the brains of older cats with dementia,' Dr McGeachan told the Daily Mail. 

'What we didn't know was whether it was actually causing damage. 

'Our study shows it is – by triggering the brain's immune cells to eat away or engulf the connections between brain cells, called synapses. 

'Losing these connections is closely linked to memory and behaviour changes... and it mirrors almost exactly what happens in people with Alzheimer's.'

According to Dr McGeachan and colleagues, cats may also benefit from human–designed Alzheimer's treatments (including recently approved anti–amyloid drugs).

'We can use cats to study the disease and develop treatments that could help both animals and people with dementia,' he added. 

The new study, published in the European Journal of Neuroscience, shows that cats are a valuable model for studying dementia in people.

Because of the similarities in the brains of cats and people, scientists could potentially dissect cat brains in the lab to understand more about Alzheimer's in humans.

Previously, researchers have studied genetically modified rodents, but these do not naturally suffer from dementia, so cats may be 'a more accurate model of the disease than traditional laboratory animals', ultimately benefiting both species and their caregivers. 

'Feline dementia is so distressing for the cat and for its person,' said Professor Danielle Gunn–Moore, study co–author and expert in feline veterinary medicine at the University of Edinburgh.

'It is by undertaking studies like this that we will understand how best to treat them.

'This will be wonderful for the cats, their owners, people with Alzheimer's and their loved ones.'