How to Control a Machine with Your Brain

For eighteen years, Jan Scheuermann has been paralyzed from the neck down. She is six feet tall, and she spends all day and all night in a sophisticated, battery-powered wheelchair that cradles her--half sitting, half reclining--from head to toe. In effect, the chair has become an extension of her body. To navigate the world in it, Scheuermann manipulates a cork-tipped joystick with her chin. She can move in this way with remarkable agility, but her height, combined with the bulk of the chair and the unrelenting nature of gravity and matter, can limit her.