Trouble sleeping is known to be one of the earliest symptoms of dementia among humans.
And now, scientists have begun to see parallels in our pets, with dogs experiencing similar disruptions when snoozing.
In a Frontiers study of 28 senior dogs, those with symptoms of Canine Cognitive Dysfunction (CCD) were seen to take longer falling asleep and spend less time napping.
Higher dementia scores were also correlated to less rapid eye movement (REM) sleep, meaning that these dogs were less likely to dream.
‘Our study is the first to evaluate the association between cognitive impairment and sleep using polysomnography—the same technique as used in people—in aged dogs,’ Senior author Dr. Natasha Olby at North Carolina State University said.
Trouble sleeping is known to be one of the earliest symptoms of dementia among humans. And now, scientists have begun to see parallels in our pets, with dogs experiencing similar disruptions when snoozing (stock image)
The study pool of dogs were aged between 10 and 16 years old, corresponding to the average lifespan of a canine.
To start, owners were asked to rank the characteristics of their beloved animals, including the severity of any CCD symptoms.
CCD – also known as doggy dementia -is related to the aging of a dog’s brain, leading to a deterioration of awareness and memory.
Symptoms can include an avoidance of social interactions, disorientation and anxiety.
Scientists also then performed their own examination of the dogs, looking for any other signs of the condition.
After compiling these results, it was found that 28.5 per cent had severe dementia, while 14.3 percent and another 28.5 per cent had a moderate or mild form respectively.
These dogs then entered a sleep clinic where scientists could analyse their eye movements in addition to their heart and muscle activity.
All but two dogs entered a state of drowsiness, before 24 then entered a state of non-REM sleep which sees brain activity become quieter and slow down.
Then, just over half fell into REM sleep – the state at which dreams are more likely to occur with the brain becoming more active.
Interestingly, dogs with higher dementia scores took longest to fall asleep and stay in a period of both non-REM and REM sleep.
Experts say that pooches and humans exhibit similar symptoms in the onset of dementia (stock image)
Scientists looked at oscillations in electrical brain signals to analyse this, which are usually taken by small sensors that rest on the head of a test subject.
‘In people, slow brain oscillations are characteristic of SWS and linked to the activity of the so-called ‘glymphatic system,’ a transport system that removes protein waste products from the cerebrospinal fluid,’ Dr Olby said.
‘The reduction in slow oscillations in people with Alzheimer’s, and the associated reduced removal of these toxins, has been implicated in their poorer memory consolidation during deep sleep.’
The results follow another study last year which found that the risk of doggy dementia increases by 52 per cent every year after a dog turns 10.
Inactive dogs have a 6.5 times greater risk of CCD than those that get regular exercise.
At the time, researchers wrote: ‘Given increasing evidence of the parallels between canine and human cognitive disease, accurate CCD diagnosis in dogs may provide researchers with more suitable animal models in which to study ageing in human populations.’
