It is tough to watch a dog deal with issues associated with aging. A senior dog that gets lost at home or starts showing more anxiety may be exhibiting signs of dementia. But by the time these signs show up, the decline may have been underway for years.
To catch that hidden decline earlier, University of Arizona researchers have developed a roughly 40-minute assessment called CANID, short for Cognitive Assessment for Neuropsychological Impairments in Dogs. Using three simple tasks that measure memory and behavioral flexibility, CANID can detect subtle cognitive impairment in dogs when they are about 7 or 8 years old – well before the overt signs of dementia appear at around 12 to 14 years of age.
"We can't ask them questions; we can't tell them, 'OK, this is the test of your memory,'" said Dr. Evan MacLean, the study's senior author and a professor in the U of A's College of Veterinary Medicine .
So instead, the researchers let the dogs show how good their memory is and how well they can hold back an impulse using games played for treats.
The study , recently published in the journal Animal Cognition, was led by Stephanie Hargrave, a Ph.D. student in the Department of Psychology .
Most existing tools for detecting dementia in dogs, according to Hargrave, are owner surveys, which only catch problems when they are obvious.
"Unfortunately, by the time these measures identify dogs as having canine cognitive dysfunction syndrome, their cognitive impairment is often quite severe," Hargrave said.
The test isn't something owners can run at home. It requires trained staff and specialized equipment. But it helps scientists study large numbers of pet dogs and understand what keeps aging brains healthy, which could eventually inform preventative and therapeutic strategies for pet owners.
The study involved three tasks. In the first game, a dog watches a treat go into a clear tube that is opened at the ends. The dog has to resist bumping its nose into the front and go around to the opening instead, a skill that tends to slip with age.
In the second game, the dog watches a treat being hidden behind one of four wooden barriers and has to remember where it is after waits of up to 40 seconds, sometimes with a distraction during the wait time.
The third game, also MacLean's favorite, lets the dog walk around a barrier to reach food. The researchers secretly block one route behind the barrier and switch it each time the dog learns the open path.
Each dog's performance across the three games is combined into a single score. The team tested 239 dogs in Tucson and California and retested many of them six months and a year later. The scores remained consistent at levels comparable to that of human neuropsychological tests.
The results also confirmed an interesting pattern the team has seen repeatedly. One might assume that large breeds like Great Dane, which have shorter lifespans, might face cognitive decline sooner. But MacLean said that that's not how it works – there seems to be just one trajectory of cognitive decline in dogs, he said.
"If you're a big dog, you probably die before you reach a point in that trajectory where you would have experienced major cognitive impairment," MacLean said.
That makes small dog breeds like Chihuahuas, which live long enough to reach that age, more likely to experience decline.
The work could also matter for humans. Old dogs with dementia can develop amyloid plaques in the brain similar to those seen in Alzheimer's disease in humans.
"Dogs drink the same water we do. They breathe the same air," MacLean said.
He believes that by studying animals that live so closely alongside humans, there is major potential for discoveries that will help both species.
Tucson-area owners interested in dog aging can sign their dog up for the lab's ongoing cognitive aging studies through Arizona Canine Dog Cognition Center . Owners elsewhere in the U.S. can enroll their dogs in the Dog Aging Project , a nationwide study following 50,000 dogs, of which U of A is a part. Participants may get the chance to try a set of simpler cognitive games the team designed to do for owners at home.
"We see the development of CANID as an exciting milestone – it's a tool that is going to help us do a lot of important future research," MacLean said.
For Hargrave, the work is also personal, as her own dog Roxy, a Chihuahua mix, turns 11 next January.
"I'm especially interested in what I can do to prolong her cognitive health and prevent decline," Hargrave said.
