A pet owner has captured the heartbreaking moment a senior rescue dog battling dementia "thinks he is a puppy again."

Every time Pixie switches from his normal, reserved demeanor to that of a playful, more affectionate young pup, his owner, Summer Nadya from Camden, Maine, gets emotional.

"It makes me cry every time because I always wanted that experience of seeing him as a happy, young puppy," Nadya told Newsweek. "It's an experience I have always wanted with him. It's an experience I don't think he ever got."

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Nadya was driving back from a music festival one dark night back in 2017 when she spotted something that made her slam on the brakes.

"I saw these little eyes glowing in the road," she said. "I thought it might be a skunk or a raccoon, so I pulled over to shoo it out of the road."

As Nadya got closer, she quickly realized it was a small dog. They were in the middle of nowhere, so she figured it was the right thing to take him to a vet to see if he had owners out there looking for him.

Not that she had much say in the matter; Nadya said Pixie had already "trotted over to the car and just jumped in the open door" while she was weighing up their options.

However, as they headed home, Nadya quickly began to realize Pixie was in a bad way. "He was in awful shape, matted, covered in filth, sand, and stunk like rotted fish and crabs, covered in fleas and ticks," she said.

Multiple baths and over three hours of clipping and brushing followed later that night, with Pixie eventually emerging as a gorgeous white Maltese, rather than the decidedly brown dog that had gotten in their car.

It was clear that Pixie had been through a lot. "He didn't trust us but was agreeable enough to be with us. At night, he chose to go off and sleep by himself," Nadya said. "He wouldn't eat dog food, even though he was clearly starving."

He dined out on leftover hot dogs that first night before a trip to the vets the next day revealed the extent of Pixie's issues. He had Lyme disease and anaplasmosis. His teeth were rotten and in need of removal, while there was an ongoing skin condition that left him covered in scabs. Multiple medications would be required.

Finding Pixie's original owner was discussed, but Nadya recalls the moment the vet looked her dead square in the eyes and told her: "I wouldn't give him back to wherever he came from; he has clearly been through years of neglect."

Though they wrestled with the idea a little longer, eventually the decision was made by Nadya and her partner to keep Pixie. Though Nadya had been the one to rescue Pixie, he quickly came through for her, too.

"I was dealing with autoimmune issues," Nadya said. "There were days where I couldn't get up, and he would just lay as close to my legs and feet or near my head and not care about going outside."

Over the next seven years, Pixie underwent an amazing transformation. Nadya saved up the money to have his rotten teeth removed, and they found a medication that helped treat his skin condition.

Pixie was finally living the life every dog deserves. "He is an amazing guy. We have traveled all over the U.S. with him; flown with him," Nadya said. "He loved the beaches of Puerto Rico and Martha's Vineyard. He has such an adventurous spirit."

But then, last year, Nadya started to notice him "slipping away" with the onset of dementia. "He was a very smart, resourceful guy, and all of a sudden, he would stand facing a corner barking like he couldn't get out," she said.

Dog dementia or Canine Cognitive Dysfunction Syndrome (CCDS) is a common diagnosis among aging pets. In some cases, the symptoms can start even earlier. A 2009 research paper published in the Journal of Small Animal Practice said 22.6 percent of dogs 9 or older had been found to display some form of cognitive impairment.

For Pixie, the condition began to manifest itself in a very different way. "Even though he likes to lay near me, he was never the type of dog that wanted to be held or licks your face. He is totally OK with getting picked up to help him on the couch or the bed or to help move him, but not to be cuddled," Nadya said.

"That's one of the things that has recently changed. He will get all sassy and fun and play like a puppy and then come up to you and ask to be held and cuddled where he will nuzzle his head into your neck and chest."

Now the rescue is living on a 15-acre farm with her owner's three other dogs, Nadya is eager to embrace Pixie's puppy side and make him as happy and comfortable as possible.

"No matter what when he wants to snuggle, I stop whatever I am doing and do it. Even if it means being late for work," Nadya said. "I try to see those moments where we both get that experience as a little gift."