Tic

A tic is typically defined as a sudden, repetitive, stereotyped, nonrhythmic movement (motor tic) or sound (vocal tic), although not all are sudden.

Tics can be simple or complex.

There are different tic disorders:
 * transient tic disorder
 * chronic tic disorder
 * chronic motor tic disorder
 * chronic vocal tic disorder
 * Tourette's syndrome (technically also a chronic tic disorder)