<qa>  What is the term for tricks?The purpose of this study is to collect and organize information concerning a phenomenon known as sensory tricks or Geste antagoniste in focal dystonia. Sensory tricks, which we will refer to as tricks since some involve motor as well as sensory input, are various stimuli used by dystonic patients to transiently diminish their spasms Jankovic and Fahn 1993. The phenomenon of tricks is evidence for the abnormality of sensorimotor integration in focal dystonia, yet it is little studied or understood. A survey of the history and characteristics of tricks will lead to a better understanding of this puzzling phenomenon, and a step toward the understanding of the mechanism of focal dystonia. 