Multi-Species Dementia

By Lorena Sordo

Lorena Sordo is a PhD Candidate at the Royal Dick School of Veterinary Studies, University of Edinburgh.

Animals have become a crucial part of our lives and important members of our families. The benefits they bring to our lives are undeniable; they improve our health and well-being, they make us more active, they bring us joy, happiness, love, and companionship.

Nowadays, therapy animals/pets are becoming more and more common as they significantly improve the well-being of people with autism and mental health problems. We have also read in previous blog posts from Dr Louise Ritchie and Rebecca Lassell about assistance dogs from the Dementia Dog Project and horses from Riding in the Moment, and the ways in which the animals in both programs enhance the quality of life of people living with dementia and Alzheimer’s disease.

Personally, cats have helped me during difficult events throughout my life, the most recent being the current pandemic that is affecting us all. My cats are that much needed fresh air when I feel overwhelmed by work; when they lie on my keyboard while I am trying to write my thesis or when they decide that the best place to sit and groom themselves is in front of my laptop camera, while I am in an important meeting. My cats are also the best nurses; they have helped to ease my anxiety, they purr and keep me warm when I am feeling ill, and they make me laugh when I am feeling down.

I was fascinated by the blog post written by Professor Louise Locock and by Mr Pink’s story. As a cat lover myself, I found her blog so interesting, especially as she talks us through something that for many people (including myself) can be so difficult to confront, which is the ageing of a beloved pet – with all its challenges – and their inevitable death. For me, this blog hit close to home for two reasons. The first one is very personal, the recent death of one of my cats, Cuco, who was a playful, loving ball of fur who loved to sprint from one room to another and to sleep under the duvet. The second one is more from a professional perspective, because my area of expertise is feline ageing and dementia (yes, cats get it too).

Since I can remember, I have always loved and cared for animals; for this reason I decided to become a veterinary surgeon. I must confess that, even though I love all the animals, I do have a special and profound love/obsession for cats. They are such majestic, interesting, elegant creatures… and they know this. As Terry Pratchett wisely pointed out: “In ancient times cats were worshipped as gods; they have not forgotten this”. This is, in my opinion, what makes them even more special.

Since I became a vet, I have always shown interest in feline medicine and cat welfare. I came to Scotland (with my cats) in 2015 to pursue a MSc in Applied Animal Behaviour and Animal Welfare, focusing on cat welfare. Currently, I am a final year PhD student, soon to submit my doctoral thesis in feline dementia at The University of Edinburgh.

At the beginning of my PhD, four years ago, I was mostly interested in the veterinary perspective of feline dementia, to understand its neuropathology, its potential causes and to find better and more efficient ways to diagnose and manage it. However, as I started to learn more about it, I found that the age-related changes in elderly cats with dementia are not too different to those in elderly people with Alzheimer’s disease. Aged cats develop behavioural, anatomical, and neuropathological changes similar to those seen in humans. It turns out that cats have not only helped us to enhance our lives with their unique presence, they are also becoming strong contenders in the search for accurate natural models for the study of Alzheimer’s disease. The thought of this really intrigued me.

I also became interested in drawing synergistic comparisons between species; what we know to happen in the brains of cats with dementia might help us to unravel the mechanisms behind human Alzheimer’s disease, and vice versa. Before the pandemic, I was lucky enough to visit Professor Elizabeth Head’s laboratory at The University of California Irvine. During my visit I learned an automatic technique to quantify protein deposition (i.e., beta amyloid and tau) in the brains of cats. This has helped me to draw objective and robust comparisons between cats and humans regarding the presence, distribution, and progression of these proteins within the elderly brain.

But cats are not the only animals that have shown to develop dementia, as dogs are known to develop it too. Interestingly, other animals also produce similar neuropathology, such as degus, dolphins, wolverines, and donkeys; however, the effect on cognition has not yet been assessed in these species.

It is clear to me that animals fill up and massively improve our lives, whether they are companion or assistance pets. However, little did we know, years ago, about all the knowledge that they would provide us. It will always amaze me how much animals can give us and how little they ask in return, with a rub on the belly or a scratch under the chin being enough. And now, after writing this short blog post, I feel I love animals even more than before and I am so very grateful for the two kitty cats, Maki and Ogra, who form part of my family.