Could your dog have dementia?

Here’s what you need to know about pet senility.

Chester was the pup of his pack back in the day.

“He was a spunky little thing,” said owner Lucie Greco, a dog groomer. “Always on the go. Just a happy soul.”

But last month, the little Pekingese turned 14 — up there in dog years. Lately, Chester has been having house-training “accidents,” Greco acknowledged delicately. He never used to. At times now, he seems a touch confused, like the other morning when Greco woke him a bit too quickly. Chester nipped her.

“That’s why I think he’s getting a little, you know, dementia,” Greco said. “He’s going a little off.”

Dogs and cats, like their human companions, can suffer the ravages of cognitive decline, also known as senility or dementia. There’s a body of research that says it also appears to happen in the wild to some species of mammals and birds, even insects. However, animal experts add, creatures living in unprotected environments probably don’t survive very long with serious cognitive loss.

Domestic animals, especially those that share our homes, are another story. Advances in veterinary medicine have made it possible for pets to live longer, just as medical breakthroughs have extended people’s lives. Much of the research has focused on dogs; their decline has its own name — canine cognitive dysfunction (CCD).

“Certainly as we see dogs get

older and older, we do see a higher proportion of them with signs” of CCD, said Evelyn Galban, associate professor of neurology and neurosurgery with the University of Pennsylvania veterinary school.

In some dogs, cognitive dysfunction can start to manifest as early as 8 years of age. It’s not as common in cats, but when it does occur, it tends to happen at age 15 or over, Galban said.

The physiology of the decline, while still very much in the research stages, may cross species, too. Studies on the brains of dogs with CCD that have died have shown protein plaque build ups, not unlike those of humans, said Galban.

Before deciding that your four-legged friend has dementia, experts stress ruling out other health problems. A pet that has started soiling indoors, for example, may have a treatable bladder infection or kidney problems, not dementia.

There are other signs of cognitive dysfunction. A big one is a notable increase in anxiety. Senior dogs may seem alarmed by people or animals they know and even have always liked, including family members. Their sleep patterns can change greatly; they may start pacing through the night or engaging in nocturnal meowing or barking for no apparent reason. (That can also be a sign of thyroid problems — something else to rule out.)

Like people, animals with dementia can have times of total lucidity, but also periods of being confused and disoriented.

Pets with cognitive dysfunction may lose interest in activities, even foods, they used to enjoy. Some pets will just stare at walls, said Evan Gandler of Sterling Veterinary Associates in Stratford.

“The owners will say, ‘He just stands out in the yard and stares, and we can’t get him in,’ ” Gandler said.

Cognitive decline and the behavioral changes that can go with it can be perilous for pets. It’s not unusual for senior pets to be surrendered to the pound or even abandoned. While some owners will seek to prolong their pets’ lives, others may feel that they don’t have the resources to care for animal with cognitive issues.

While dementia can’t be cured, there are things that may help manage symptoms.

For some animals, antianxiety medication may be called for. There are also prescription pet foods that support brain health, as well as some nutraceuticals, or diet supplements, that can have anti-anxiety or other cognitive benefits. Some very old animal friends may need the fallback of house-training pads.

Creating a routine of exercise, even one that’s very gentle and minimal, is also a good idea, but it should be done in a way that doesn’t create more anxiety. And while there isn’t sudoku for pets, animal brains benefit from new experiences and learning new things. Galban suggested checking out pet toys designed to help give your pet some mental exercise.

“To keep the brain healthy,” Galban said, “you really need to challenge it.”

Chester the Pekingese has chosen his favorite playmate to keep him active. That would be Lucie Greco’s mother, Jane Knipe. She moved from England to live with her daughter’s family several years ago. Chester is with her all day while Greco works at her grooming shop and pet day care, Lucie’s Barkingham Palace.

The dog sits beside Knipe on the sofa when she watches television, accompanies her outdoors, and cuddles next to her at bedtime. Knipe, 69, a retired nurse’s assistant, cared for people with dementia. She’s fine with Chester.

“He can get a bit snippy,” Knipe said. “But you know what? I think I may get snippy when I’m his age.”

Sometimes, when he’s pouncing on a dog treat, she catches a glimpse of the old Chester.

“He changes,” Knipe said. “He is like a puppy.”

Some things, though, don’t change. She added: “He’s a good little dog.”

ELIZABETH ROBERTSON/PHILADELPHIA INQUIRER Lucie Greco, left, and her daughter Isabella, 7, laugh as their 14-year-old Pekinese, Chester, plays with a treat.