How to know if your dog has dementia: the seven most common signs and symptoms

Picture of Dr. Else Verbeek
Dr. Else Verbeek

Dog behaviour scientist and consultant.

I felt devastated when our lovely family dog, Thierry, couldn’t keep up with us anymore when he was about 12 years old. He would pace around the house aimlessly. He seemed to get lost even in our own backyard and could not do the things he normally enjoyed. In the end, after many months of him getting progressively worse, his quality of life was so poor that we were left with only one decision.

It is many years ago now, but it left an impact that I haven’t forgotten until today.

Picture of old grey dog

Perhaps you have you noticed a change in your senior dog’s behaviour recently? Maybe she’s getting a bit slower and less mobile, but isn’t that normal for a senior dog?

You would be surprised to know that dementia, also called canine cognitive dysfunction (CCD), is very common in dogs that are older than eight years. Between 14 and 30% of dogs between the ages of 8 and 11 are affected, and up to 90% of dogs aged over 13. 

Age is a funny thing in dogs, and smaller breeds (chihuahuas, dachshund, etc) tend to get older than larger breeds (for example, labs, german shepherds, etc). So you may see changes earlier if your dog is of a larger breed. And if so, chances are that he is starting to develop dementia.

What is dog dementia?

Dementia in dogs is very similar to human dementia. A dog with dementia will develop specific pathologies in the brain that are similar to humans. These pathologies are caused by the build-up of proteins, β-amyloids, that form plaques. Dementia will change your dog’s day to day life. Perhaps not so much in the beginning, but the condition gets progressively worse as your dog ages.

Your dog’s memory, especially long-term memory, will gradually start to deteriorate. Your dog may not remember the cute little puppy you met on last week’s walk. Or, when things get worse,  she forgets where to find her bed and struggles to find her favourite toy in the yard. 

Your dog may also be slower to respond to your signals and take longer to understand what you want from him. And this is not simply because his physical fitness gets a little less when he ages. No, it is because his brain is struggling to keep up!

It is also harder for your dog to focus and maintain attention, so tasks that were easy before, may now take some more patience and involvement from your part. 

Your dog may also struggle with impulse control, so don’t be surprised if he starts to snatch pieces of food or growl at the neighbor’s dog. Even though he never did this before. He really can’t help it, his brain is not making it easier on him!

Dogs with dementia also struggle more with stress. For example, senior dogs showed a higher stress (cortisol) response when left alone with a stranger, even though they did not express this increased stress in their body language. Dogs with dementia can also start to increase barking and whining in the middle of the night.

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The seven most common dog dementia signs and symptoms

Picture of old brown dog

Some dogs may show a change in only one of these symptoms, while others may be affected by all. 

Exploration, play and the response to commands often deteriorate the quickest, while fears and anxieties may increase rapidly. So especially keep an eye out for these symptoms, because these are early warning signs of dementia.

The degree to which dogs are affected also varied widely. Some dogs only ever experience mild dementia. But if you notice that your dog’s dementia is getting worse, make sure you see your vet!

Dog dementia and aggression

Dog aggressive behaviours increase in older age. An epidemiological study showed that the risk of dog bites is higher in dogs older than 7. Veterinarians reported that aggression was the second most common behavioural problem in dogs (after destruction), especially aggression towards people (61% of vets). 

Make sure that you keep an eye out for increased aggression, especially if you have young kids and other pets. Make sure to learn what situations trigger your dog’s anxiety, and learn how to read dog body language so you can prevent dog bites (see the canine ladder of aggression in this post).

Dog dementia and euthanasia

There is no cure for dementia, but there are ways that the symptoms can be alleviated. Once you rule out pain or other illnesses, there are plenty of ways you can maintain your senior dog’s quality of life for longer. 

However, for some dogs, the symptoms can be so severe that you may wonder if dog dementia is a reason for euthanesia. Although euthanasia can be used to relieve suffering in dogs, their health and welfare should always be considered before making this choice, and suffering should be minimized. 

A worrying statistics is that 69% of dogs older than 10 did not see a vet in the 18 months before euthanisea.

If you recognize some of the signs and symptoms of dog dementia, you should have a discussion with your vet as soon as possible. Dog dementia severely impacts your dog’s quality of life (and yours!!!), and dog dementia euthanasia is not something you should take lightly. In the end, you are the only one that can make this decision.

Did we in the end euthanize our family dog Thierry? Unfortunately, we were left with no other choice. And we took this decision after careful consideration and consultation with our vet.

It still bothers me today, and  I am wondering if there is more that we could have done. 

Luckily I am now a researcher, so there should be plenty of ways I can help senior dogs. I just submitted a proposal for a research project to find more effective ways to slow the progression of dementia, and hopefully even prevent it. I also want to find easier ways to diagnose dementia (both behaviourally and physiologically), because dog dementia is currently under-diagnosed. Let’s hope this research gets funded.

Our lovely cuddly senior dogs deserve a worthy end of life!

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Canine Cognitive Dysfunction (CCD) scores correlate with amyloid beta 42 levels in dog brain tissue.
Insights about the Epidemiology of Dog Bites in a Canadian City Using a Dog Aggression Scale and Administrative Data 
Does the attachment system towards owners change in aged dogs?
The epidemiology of behavioural problems in dogs and cats: a survey of veterinary practitioners