Involuntary movements of one hand that accompany and mirror intentional movements of the opposite hand.
Comment:
Mirror movement refers to simultaneous contralateral, involuntary, identical movements that accompany voluntary movements. Erlenmeyer first used this term in 1879. The definition of mirror movement as involuntary, synkinetic mirror reversals of an intended movement of opposite side was coined by Cohen et al. in 1991. These movements are soft, neurologic signs, seen uncommonly in clinical practice.