Elderly dogs with declining cognitive function have trouble sleeping, just like humans with dementia do, according to a recent study published in the journal Frontiers in Veterinary Science.
As they age, dogs can develop a condition known as canine cognitive dysfunction syndrome (CCDS), which is similar to Alzheimer’s disease in humans. Researchers have previously identified a relationship between dementia and poor sleep in humans, and now they’ve found evidence that suggests the same link exists in dogs. If true, this knowledge could help pet owners catch cognitive decline earlier and start treatment for their dogs sooner, scientists say.
To understand how cognitive function relates to sleep in man’s best friend, researchers fitted 28 older dogs with electroencephalogram (EEG) electrodes on their heads, which non-invasively recorded the animals’ brain activity while they took two-hour-long afternoon naps. Though the pooches were snoozing in a lab, scientists tried to make them comfortable—the dogs were tucked safely into their beds from home, with white noise playing in the background and a staffer nearby to ensure their safety. The electrodes tracked how long the canines spent in various stages of sleep and wakefulness, a process known as polysomnography.
The dogs ranged in age from 10 to 16 years old. Male and female, as well as mixed-breed and full-breed dogs, participated in the study.
Separately, researchers also evaluated each dog’s cognitive abilities by running them through a series of tests and asking their human owners a list of questions known as the Canine Dementia Scale Questionnaire.
After comparing the results of these two experiments and considering each animal’s age, the scientists noted a correlation: Dogs with worse cognitive function spent less time in both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, during which the brain performs critical functions that can combat the symptoms of dementia.
“In NREM, the brain clears toxins, including the beta-amyloid proteins that are involved in diseases like Alzheimer’s,” says study co-author Alejandra Mondino, a veterinary neurologist at North Carolina State College of Veterinary Medicine, in a statement. “REM sleep is when dreams happen, and this stage is very important for memory consolidation.”
For owners of dogs with CCDS, the findings might not come as a surprise: They’ve likely experienced the sleeplessness first-hand as their pets’ cognitive function declines. Dogs with the condition are often awake at night, pacing and making vocalizations while their owners are trying to sleep. Dogs with CCSD spend more time awake, and when they do manage to doze off, their “brains aren’t really sleeping,” Mondino says in the statement.
The results don’t explain why sleep and dementia may be linked. However, they could help veterinarians and pet parents identify cognitive decline, which is helpful for treatment.
“With a chronic neurodegenerative process, of course we’d love to be able to intervene sooner rather than later,” as study co-author Natasha Olby, a neurologist at North Carolina State College of Veterinary Medicine, tells CNN’s Sandee LaMotte.
Researchers haven’t discovered a cure for dementia in humans or dogs, however, veterinarians may be able to prescribe medication or suggest treatment options, such as changing an animal’s diet or promoting exercise; they can also offer symptomatic relief for insomnia and sleep disruptions, such as melatonin and anti-anxiety medications.
If dog owners start to notice shifts in their pet’s sleep patterns or other behaviors, it’s best to consult with a veterinarian, says Nick Sutton, a health information officer at The Kennel Club in the United Kingdom who was not involved with the new research, to the Guardian’s Nicola Davis.
“Humans with dementia often have disturbed sleep, and this research suggests that we’re not alone,” he tells the Guardian. “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.”