Inclusion Criteria:  unresponsive wakefulness syndrome/vegetative state (UWS/VS) or minimally conscious state (MCS) following traumatic brain injury (TBI), intracerebral bleeding, ischemic infarction, or hypoxic brain injury Medical clearance by a physician 18-75 years old Mobilization into standing for at least 10 minutes without signs of orthostasis  Exclusion Criteria:  Time since injury less than 4 weeks or more than 6 months Mobilization into standing lasts more than 30 minutes Severe osteoporosis Muscle tone that prevents joint motion (Modified Ashworth Scale (MAS) 4) Unstable fractures Decubiti on areas contacted by robotic mobility device (i.e. heels, tibia, greater trochanter, ischial tuberosity, sacrum)  Inability to fit device requirements*  Height 4'8"-6'4", Weight 88-222 lbs., Hip Flexion 0-90˚, Knee Flexion 0-90˚, Plantigrade