CARRBORO - For 16-year-old Kayley Thorpe, it's not a matter of whether she will have a spasm that might send her crashing to the floor. It's when.

The Wilson County teen has Tourette syndrome, a condition that causes uncontrollable ticks and sounds. She has used a cane and wheelchair, and has been lain gently on a mat when she has spasms that she says can look like a seizure.

But now Thorpe has a new aide to help calm her condition: a 69-pound golden retriever named Mack that has been trained to gently apply pressure when his owner is in trouble, or to stand still so Thorpe can brace herself against a fall.

The Carrboro nonprofit Eyes Ears Nose and Paws held a graduation ceremony, officially transferring Mack to Thorpe, Saturday at the Century Center in Carrboro. About 100 people attended.

EENP, whose motto is "partnering people with dogs," began in 2008 to help train animals to work with people who can typically wait two to five years for an assistance dog, Executive Director Maria Ikenberry said.

Saturday's ceremony recognized the agency's supporters, the "puppy parents" who help raise the dogs during a year and a half training period, and the new team of Thorpe and Mack.

The blonde teenager from Lucama, N.C., met Mack at an open house last summer when the dog was still a "fuzz ball," she said. She didn't know until just two weeks ago that she would be his new handler.

The two then completed an intensive training that included a weeklong "umbilical" exercise that kept them leashed to one another 24/7 to promote a close connection. She looped the leash to the bathroom door when she took showers and to her night table when she slept.

Thorpe clasped her hands and smiled broadly on stage Saturday. She told the crowd she loved dogs even before her condition became disabling, triggering spasms that can last hours. Deep pressure applied to her legs can help stop an attack in minutes.

"The thing is it's very strange to have a person leaning on me," she said. "But Mack, he can do it for me."

A simple "up" command, and the golden retriever gently climbs into Thorpe's lap, placing his front paws on her thighs and nuzzling her neck. If Thorpe is on the floor, Mack is trained to lie on her stomach to calm her.

Each assistance dog costs $20,000. EENP requires clients to pay at least 25 percent of the cost, and offers scholarships to help pay for the rest.

EENP placed its first two assistance dogs in August 2010 and has seven in training.

The agency is now training two terrier mixes from the Orange County Animal Shelter to aid people with diabetes. Assistance dogs build on the work of guide dogs for the blind, Animal Services director Bob Marotto said, as their abilities to help people with psychological needs as well as physical needs become better known.

"These dogs represent our continuing co-evolution," he said.

For Thorpe, Mack brings some immediate benefits.

"I don't have to have a person with me all the time," she said. "I don't have to worry about stuff anymore."

Last week, she said, they went to the mall.