Jancy Chang, a high school art teacher in San Francisco, had been painting since she was a child. She varied her technique from Western-style watercolors to classical Chinese brushstrokes, but she always strove for realism: painting landscapes and people in social settings as literally as she could. Then, in 1986, at age 43, she began to have problems performing her job. Grading, preparing for class, putting together lesson plans--everything that she had previously done with ease--became increasingly difficult over the next few years. By 1995 she could no longer remember the names of her students and was forced to take early retirement.