ANNAPOLIS, Md.—Valery Spiridonov looks impossibly small. He is dressed in all white, from his white button-down shirt to the white socks on his feet, which dangle at the ends of white pants and a white blanket. Breaking up the look is a black strap, which holds him to a motorized wheelchair.

He uses his left hand, which he can still move, a little bit, to steer the wheelchair into a hotel meeting room. There, he confirms that he would like to be the first person ever to have his head transplanted onto a new body.

Spiridonov flew from Russia to be at this conference, the American Academy of Neurological and Orthopaedic Surgeons (AANOS). He joined the surgeon proposing to do the transplant,