What Older Dogs Can Teach Us About Dementia

It’s understandable that we see old age as the reason when a dog starts to behave differently. But a new study suggests the changes in their brains look a lot like early Alzheimer’s in people.

Restless nights, pacing, staring into space, getting stuck at doors or behind furniture. These can all be signs of canine cognitive dysfunction, although they’re often mistaken for the inevitable effects of getting older.

Canine cognitive dysfunction (CCD) is the dog equivalent of dementia, typically affecting dogs over the age of eight, which is why it’s so often mistaken for normal ageing.

In a study published on 6 October in the journal npj Dementia, researchers at Colorado State University and UW Medicine examined the brains of 24 pet dogs, kindly donated by their owners after the dogs died, and compared their findings with how each dog had behaved in life.

Every dog had deposits of amyloid-beta, a protein associated with Alzheimer’s disease. Age was the biggest predictor of how much they had. Dogs with dementia had more amyloid in the front of the brain, the part used for planning and thinking.

For the first time, researchers examined pet dogs’ brains using methods adapted from those used to stage Alzheimer’s in people, and matched the results to each dog’s symptoms.

The dogs’ brains matched the early stages of Alzheimer’s, but not the later ones. Those early stages are hard to study in people, so dogs, which develop these changes naturally, could help researchers understand how the disease begins, potentially helping both dogs and people. That doesn’t mean dogs get Alzheimer’s. Canine cognitive dysfunction shares some of the same brain changes, but it isn’t the same disease.

Blood samples from 14 dogs also showed a link between a protein called GFAP and amyloid deposits in certain parts of the brain. However, GFAP levels couldn’t reliably distinguish dogs with dementia from those without.

If your dog seems restless or confused, book a check-up with your vet. Many of these signs have other causes, like arthritis or sight loss, but sometimes the cause is CCD. If it is, a consistent routine, changes around the home and veterinary treatment can all help.

Sources

Original research: Alzheimer's disease neuropathological characterization of the dog brain and relationship to biofluid biomarkers and cognitive function, published in npj Dementia, 6 October 2026.

Researcher commentary:  ⁠Why Old Dogs Might Be Able to Teach Alzheimer's Researchers New Tricks, Nautilus.