There is a circle of 10 empty chairs in the center of the room. Rows of fluorescent lights glow brightly from the ceiling, waiting for something to move beneath them. A few minutes before 4 p.m., a woman and a man enter.

For the woman, the walk from the doorway to the chairs is easy: the mind says walk and a chemical reaction in the brain tells the muscles to move, a process so dependable it is thoughtless. For the man it is not so simple, as his legs are less willing to cooperate. The walk requires the arm of his spouse, a patient source of support to help him see the journey through. When he gets to his chair, he looks tired.

Two more people enter the room. The seated man sees the newcomers and, with a surge of newfound energy, immediately takes hold of the chair’s arms, pushes down on them and stands. He greets them with a hug. The rest of the group all great each other this way as they arrive. Big smiles, hugs and kisses on cheeks. They say more than a perfunctory, “how are you?” They could easily be guests at a family reunion, culled from different states, seeing each other for the first time in years.

But they see each other every week.

They have attended the class designed to enhance the lives of Parkinson’s patients offered at Stony Brook’s Center for Dance, Movement and Somatic Learning since it began in February 2015. A supplement to regular physical therapy, the class serves as an exercise to increase the quality of the patients’ lives. Every Friday, after their sincere greetings, the patients and their spouses or caretakers fill the circle of chairs. With them sits Amy Yopp Sullivan, the founding director of the program.

From a glance it’s not hard to tell that Sullivan is a dancer. Her shoulders, back and chin parallel to the ground, she seems aware of the space she inhabits. Among many pairs of white athletic sneakers, she sits in the circle barefoot. Though Sullivan is the instructor, the group gives her the same warmth they give each other. She asks them about their physical therapy and families, they ask her about her job and dogs.

There’s a genuine fondness between them, but the conversation before class starts also serves another purpose for Sullivan: it helps her determine how they are that week. Are they full of energy? Are they frustrated from the heat? Agitated from a new medication? From here she decides what path the class will take.

The class usually begins with patterns of humming to stimulate the vagus nerve, the longest of the cranial nerves with motor and sensory fibers. Next, the group echoes her exaggerated laughing. It’s not long before both Sullivan and the group are actually laughing. It’s a stiff competition, but Sullivan is smiling the widest.

When she was an undergraduate, Sullivan saw a film of a dance therapist working with a child in an autistic spectrum. The therapist mimicked the child’s movements, stiffening her hands and crawling on the floor. During this process, the child slowly opened up to the therapist and began to trust her.

“It was the therapist’s way of saying, ‘I can do this with you,’” Sullivan explained. “She found a doorway in.”

Sullivan brought the sentiment shared between the therapist and child into the Parkinson’s class, finding her own doorways in. Using what she calls “the eye of dancer,” she knows what the patients need before they even know it themselves; when to help lift an arm, when to put on rock music or Louis Armstrong and Ella Fitzgerald’s “Summertime.”

Sometimes during the class, the patients cry. Often they laugh. Their movements are simple but graceful. They draw imaginary lines across the room with a swing of their arms. They reach and twist. They pivot and turn. The movements are anchored by the middle of the circle, each person a spoke on the same wheel. It’s beautiful, and they never leave the chairs.

“It was during my first solo performance,” Sullivan recalled, describing the moment she realized that dance had therapeutic abilities. On stage, surrounded by live musicians, Sullivan lost her balance.

“I was so frustrated with myself,” she said. But backstage, she was met by crying spectators who told her how beautiful her performance was, and she could see in their faces that they were moved and that she had moved them.

“That’s when I realized dance is way beyond my own individual experience. Through dance I saw that sometimes people were healed.”

Sometimes they cry, sometimes they laugh, and sometimes they are healed. There are changes in the patients each time, though they don’t always last. Sometimes they come in with walkers; other times they don’t. Because Parkinson’s has no cure, all the family, caretakers and Sullivan can do is help the patients endure the challenges.

At the moment Sullivan is in pursuit of more chairs with arms, a necessity for someone with Parkinson’s to participate in the class, thus allowing more people to attend. She is also eager to work with scientists to test the effects the dancing has on the patients. The class, Sullivan clarifies, is first and foremost a think-tank.

“The why and how,” Sullivan said, “that’s for the scientists to figure out. It’s an ongoing process. It’s what we share as scientists and artists, the unifying territory of discussion. For it to work, it must be a process.”

Toward the end of the session, Sullivan holds out her hands and describes an invisible object. It’s light and big, she tells the class. They take turns tossing the object to each other. They exaggerate their movements, pretending as though the space between their hands is light and big. They laugh when a quiet but mischievous man deviates from the plan, pretending the item is not light and big, but instead small and heavy. In that moment, there’s something being transmitted between those 10 beings, something only they can understand, something profoundly beautiful.

You can see it.