Researchers are now seeking to expand the study to 36 additional volunteers, whom they'll follow for five years. The scientists "need to test more patients that will be a little more diverse to get a better idea of who will be responsive," lead researcher Reggie Edgerton of UCLA wrote to Popular Science in an email. The current participants are active men in their early 30s or younger. Edgerton and his team want to test study participants who are older, as well as women. The team remains focused on people who have a complete paralysis diagnosis and have been paralyzed for a year or more.