From loud snores to twitching paws, dogs often appear to have a penchant for a good snooze. But researchers have said elderly canines with dementia appear to spend less time slumbering than those with healthy brains – mirroring patterns seen in humans.
It has long been known that people with dementia can experience sleep problems, including finding it harder to get to sleep. Researchers have also found changes in the brainwaves of people with dementia during sleep – including decreased slow brain waves that occur during non-rapid eye movement deep sleep. These are important in memory consolidation and appear to be linked to the activity of the brain’s system for clearing away waste.
Now it seems sleep impairment may occur in dogs experiencing a condition similar to dementia in humans.
“Changes in sleep habits should be expected in older dogs, and could be a harbinger of decline in cognition,” said Prof Natasha Olby, senior author of a study at North Carolina State University.
Writing in the journal Frontiers in Veterinary Science, Olby and colleagues reported on their study of 28 dogs aged between 10 and 16 years old. The canines’ brainwaves were recorded by electroencephalogram (EEG) while the dogs took a two-hour afternoon nap.
The researchers also assessed owners’ answers to a questionnaire and each dog’s performance on a range of problem-solving, memory and attention tasks, to provide a score indicating whether the dog had, or was at risk of, canine dementia. Twenty of the dogs were deemed to have cognitive impairment, with this judged to be severe in eight of them.
Combining their data, the team found dogs with higher dementia scores took longer to fall asleep and spent less time sleeping.
In addition the team found signs that dogs with a poorer performance on a memory task experienced shallower rapid eye movement sleep.
Nick Sutton, dog health and science expert at the Kennel Club, who was not involved in the work, welcomed the study.
“Humans with dementia often have disturbed sleep and this research suggests that we’re not alone,” he said. “Discovering that dogs with dementia may spend less time in certain essential stages of sleep is a fascinating finding, which demonstrates the importance of speaking to your vet if you notice any concerning changes in your dog, including unusual sleeping behaviours.”
While there is currently no cure for human or canine dementia, Olby said the team hope to follow dogs before and during progression of dementia to identify changes early on that might serve as predictors of future problems.
“Understanding then allows us to look for ways to treat the underlying disease,” said Olby, adding successful treatments in dogs could help pave the way for treatments in humans.
“Thus it is a win win for dogs and their owners,” she said.
