Tanya was seven when she began to see sparks of violet in front of her eyes. "You're watching too much TV, I kept telling her," her mother confessed, ignoring the symptoms for a few months until the descriptions became vivid. "She would talk to us about purple lions dancing on trees and butterflies jumping on hot air balloons made of candy," her father added, pulling out a few drawings of their daughter; the art of the visual auras she perceived.

They thought the child had a creative spark until one day, while she was painting a pink sky, her right hand began to shake violently. I saw her clench her teeth, froth at the mouth, and fall to the ground. She cut her forehead with the corner of the table and jolted in blood till the tremors subsided. "What lasted less than a minute seemed like a lifetime to me," the mother described an episode from two years ago.