Shadow pays no mind to barking dogs and hissing cats. When the silver-haired schnauzer is on duty, nothing distracts him from his job as medical assistance dog.

Back in 1991, Darlene Werremeyer faced medical problems that both devastated her and put her on a path toward life with Shadow. Undiagnosed diabetes had narrowed her arteries, causing blockages to form. A wife and mother, she nearly died when an artery ruptured after a failed angioplasty procedure.

Although she survived the ordeal, the next few months brought one medical ordeal after another. Werremeyer underwent bypass surgery and was finishing her last sessions of cardiac rehabilitation when she suffered a stroke. The stroke paralyzed her vocal cords and made speaking difficult. It still poses challenges. "If I get real nervous, I can't get the words out," Werremeyer said.

During a family reunion in Yakima, Werremeyer noticed that a family member's miniature schnauzer had a calming affect on her. The pet-induced tranquility relaxed her vocal chords, allowing her to communicate more easily.

After returning to Spokane, she asked her physician about this phenomenon. Her doctor mentioned an article he'd read about the health benefits of pets and promptly wrote Werremeyer a prescription for a dog.

Soon after, her husband, John, purchased a playful 8-week-old miniature schnauzer for her.

The pooch was around 6 months old when he began acting strangely. It was two days before Christmas, and Werremeyer was feeling tired.

"I was just going to lie down and rest awhile, and he just kept pawing at my arm. I thought he wanted to play."

When Werremeyer sat up, she became dizzy. A glucose test confirmed a drop in blood sugar.

Two weeks later, Shadow frantically pawed at her again. This time he stared intently at the glucose monitoring kit on the arm of the sofa. A glucose test confirmed her blood sugar had dropped to 60. (During daytime, normal blood sugar measures between 80 and 120.)

One month later, Shadow exhibited this anxious pawing again. Werremeyer took another glucose test that confirmed Shadow's strange behavior was no coincidence. The dog was alerting his master to the plummets in blood sugar that cause diabetics to become dizzy and lose consciousness.

Paws With A Cause, a national nonprofit organization headquartered in Wayland, Mich., trains service dogs and matches them with disabled people. Michael Sapp, its chief operating officer, says Shadow's talent for sensing drops in blood sugar is similar to that in dogs who predict epileptic seizures. It's a gift that only 12 out of 65 dogs possess.

Although researchers aren't certain how dogs perform these amazing medical predictions, Sapp said it's speculated they may sense a change in brain chemistry, pick up on a form of electrical stimulation, or cue in to some subtle shift in the person's physical demeanor.

"It's a very strong bond. A lot of the clients ... say the bond is enormous, and they are one with the dog," said Sapp.

Expenses for training a service dog run around $12,000. Although these costs are usually financed by nonprofits like Paws With A Cause, waiting lists are long. Some disabled individuals grow tired of waiting and embark on the grueling task of training their own service dog.

Self-training is difficult, Sapp says, because every trace of aggression has to be trained out of the dog.

After consulting with a dog trainer, Werremeyer embarked on nearly a year of sessions and drills with Shadow. Transforming Shadow from a pet into a medical assistance dog required extensive obedience training.

Additionally, the curious canine had to learn to ignore certain instinctive behaviors, like growling when people get too close and sniffing.

"If you go into a restaurant and there's food on the floor, it's `No, no, no.' That was probably the hardest because these dogs are serious sniffers," she said.

Outings included daily trips to pet stores, discount stores and restaurants.

"We went to McDonald's; we went to Burger King. Sometimes I'd just buy a pop.

"It took nine months for him to be where I thought he was ready to be," Werremeyer recalls.

While Shadow's orange neon service-dog vest attracts attention, his perfect manners cause him to blend into the woodwork. In fact, he's so nonintrusive that several people have nearly stepped on him.

Still, Werremeyer was berated for bringing her dog into several establishments. Although Title 3 of the federal Americans with Disabilities Act allows disabled people to bring service dogs into public establishments, Werremeyer said, a Postal Service employee refused to mail her packages unless she tied Shadow up outside the building. She left in tears.

On several occasions, diners made scenes in restaurants.

A woman said she didn't want to eat in the same room as a dog and asked to be moved. One man stormed out.

However, unkind people are in the minority, Werremeyer said, adding that most individuals are supportive, albeit curious.

"People ask questions, but that's also a good thing," she said. "It gets me talking to strangers.

"For the most part, people in Spokane are really good about service dogs."

Shadow's calming presence has not only improved Werremeyer's health, it has boosted her confidence.

"He's actually a dual service dog because he also helps me relax enough where I can carry on conversations," Werremeyer said.

Before Shadow, diabetes sent Werremeyer to the emergency room three to four times a year.

"Since I've had him, I've never had to be taken to the hospital for low blood sugar. He's always caught it before I pass out," she said.

"The lowest he's ever let it go was 50."

Still, when the vest comes off, this working dog enjoys his down time.

"He loves to run after his toys, play tug-of-war and sleep," she said. "Probably one of the things he'll do that's destructive is, if I'm not playing with him enough, he'll grab a piece of paper and shred it.

"He's a typical dog."