Lying in his hospital room, on a mattress designed to protect his fragile skin, 13-year-old Achim Nurse poked his bandaged fingers at an orange button on what looked like a souped-up video game console.
Half a second later, in a social studies class discussing the Erie Canal, a 5-foot-tall steel-blue robot raised its hand.
"You have a question, Achim?" asked the teacher.
Achim is using a pair of robots--one, called "Mr. Spike," at his bedside, and its mate, "Mrs. Candy," in the classroom--to keep...