HARTLAND, Vt. — Kevin Pearce rocks side to side on what looks like a skateboard perched precariously atop a rolling pin. After settling into a comfortable rhythm, he goes through vision exercises. He offers a running commentary and makes the balancing act seem effortless.

“Muscle memory,’’ he explained, as his shoulder-length, reddish-brown hair flopped over his black-rimmed glasses.

For now, the balance board is as close as Pearce will come to snowboarding, the extreme sport in which risky, high-flying tricks placed him among the world’s best and propelled him to international fame. He was expected to contend for gold at the 2010 Vancouver Olympics before disaster struck during a training run on Dec. 31, 2009.

Attempting to land a double cork — a twisting double backflip that is one of the most difficult snowboarding tricks — Pearce smashed the right side of his head against the icy-hard edge of a halfpipe. Despite wearing a helmet, he was knocked unconscious and airlifted to the University of Utah Hospital in Salt Lake City in critical condition with a severe traumatic brain injury.

For a week, it was uncertain whether Pearce would survive. In the months that followed, he relearned how to walk, communicate, and care for himself.

Today, Pearce, 23, continues to strengthen his mind and body through balance board work, vision exercises, Pilates, and more traditional rehabilitation, regaining much of what he lost.

“Wouldn’t you say I act kind of normal and I look kind of normal?’’ said Pearce. “Well, not everything’s normal. That’s another hard thing about this brain injury. If I had a messed up voice, which a lot of people have, or if I had problems walking, people would really be like, ‘Oh, he had a brain injury.’ You can’t tell with me. But I had a brain injury. Trust me.’’

Pearce pointed out the less-apparent lingering effects of his injury — the weakness on his left side, sometimes slow thought processing, extremely distorted vision in his right eye, memory issues, mid-afternoon fatigue. Much to the relief of family and friends, however, his warm, fun-loving personality remains much the same. As a result of the injury, some traits are more pronounced, making Pearce more extroverted, more gregarious than before.

In recent weeks, Pearce has regained his driver’s license and done on-air commentary for ESPN’s Winter X Games. When talking about familiar subjects such as ` snowboarding, Pearce sounds most like his old self. New environments and unfamiliar situations challenge his higher-level thought processing.

His next big challenge and milestone will be a move Saturday back to San Diego, where he purchased a home shortly before his injury. He has been cleared to surf, but not snowboard.