TORONTO -- In a large, mirror-walled and sun-filled practice studio at Canada's National Ballet School, more than a dozen dancers are stretching out their arms as they step across the floor in time to the piano, following the moves of their instructors with earnest concentration.

But this isn't a class of young ballet students decked out in tights and ballet slippers performing pirouettes and plies, but a group of adults with Parkinson's disease engaged in a study to determine how dance might alleviate their symptoms and alter the course of their disease.

Often joined by their care partners, the 15 participants mimic the moves of instructors leading the 75-minute weekly class, first while sitting, then standing, and finally by adding choreographed steps that take them across the floor.

Their final "number" has the dancers as would-be sheriffs moseying into an Old West saloon to shoot off a few rounds in a showdown, their feet moving to the strains of a musical arrangement that includes bars from "Oh! Susanna."

They end with a celebration, a hoedown that has the dancers throw up their arms with an exuberant "yee-haw."

"My wife talked me into it," 72-year-old Bill Ferguson of Toronto said Tuesday after joining his fellow classmates for a snack and a bit of socializing in a lounge area on the school's main floor.

Ferguson was diagnosed with Parkinson's about six years ago, and while he isn't sure if the dancing is easing his symptoms, he and wife Pat Steer say they both enjoy the recreational aspect of the class and getting together with others who have the disorder.

"Music was always part of my life, in the form of jazz, mostly," said Ferguson, who also exercises at the gym every other day to try to keep his muscles from stiffening up, a symptom of the Parkinson's.

"Going to the gym and coming to the ballet program is so different. It's nice to get a different kind of movement and to enjoy ourselves more," added Steer, 68, who also takes part in the class as his care partner.

"I come for the enjoyment of it because I know we both need the movement and the socializing, and it's a lot of fun," she said, adding that dancing proves a mood-booster for both of them.

Rachel Bar, who attended the National Ballet School and now is a graduate student in clinical psychology at Ryerson University, pitched the idea of a dance class for people with Parkinson's.

Her former school, she said, jumped at the chance to offer dance to people with Parkinson's, bringing on board the Mark Morris Group's Dance for PD and Sarah Robichaud, founder of a program called Dancing with Parkinson's to help design and implement the course.

Anecdotally, at least, dance has been found to temporarily alleviate some symptoms of Parkinson's, or PD, a progressively debilitating neurological disorder that can cause tremors, rigid muscles, balance problems and slowed or frozen movements.

Bar said there seems to be something about dancing that goes beyond simply exercising or having physiotherapy.

"If you think about dance, it's not just exercise. It's cued by music, so there's a rhythmic cue. There's usually a narrative, a story that goes behind, so there's a linguistic level to it," she said.

"There's also an emotional level -- the joy of just dancing -- and also if you're getting into a certain character, there's an emotional value there.

"So really when you're thinking of dance, you're not just thinking of exercise, you're thinking of movement along with some type of dramatic expression."

Bar has teamed up with Joseph DeSouza, a neuroscientist at York University, to study how learning and executing dance steps over the 12-week course affects participants' physical symptoms as well as their brains.

Half of the 20 registered class members volunteered to take part in the pilot study, undergoing MRI brain scans about two weeks after the program began in September, which will be repeated when it ends in December.

"We have them visualize their dance while in the scan," said DeSouza, explaining that researchers will look for both anatomical and functional changes in the brain during the imaging.

"By the time we're finished the classes in early December, they would have danced this dance at least 10 times if they came to every class," he said of the "Showdown Hoedown."

"So we're going to look at this progression over 10 weeks of what happens in their brain in this auditory-to-movement network that they obviously have an issue with in their movement disorder, and see if it's comparable to controls (volunteers without Parkinson's)."

Bar said researchers hope the brain scans will provide hard scientific evidence of neurological and physical benefits of dance to people with Parkinson's, a disease that affects more than 100,000 Canadians and seven million people worldwide.

In the meantime, though, it is gratifying to see the enjoyment that participants are getting from the opportunity to step out on a dance floor.

"I know the benefits of dance," said Bar. "I know the benefits for the body, the mind, for the spirit.

"The biggest goal and the biggest joy for me in this study is to see that we're bringing dance to people who can benefit from it in so many ways and the joy that it is bringing to their lives."