Facial myokymia: a clue to the diagnosis of multiple sclerosis.

Introduction Facial myokymia is an unusual form of involuntary movement of the facial musculature which is characterized by spontaneous undulating waves of contracting muscle fibres spreading across the face. In a recent review, Gutman, Thompson & Martin (1969) were able to find forty cases reported in the world literature and added two of their own. Of these cases, in twenty-three the diagnosis of multiple sclerosis seemed 'well established, or at least quite likely' and at least ten had intrinsic pontine tumours. Thus, over half the reported cases have been associated with multiple sclerosis. The purpose of this paper is to (1) assess the incidence of facial myokymia in multiple sclerosis, (2) report three further patients with this rare syndrome, and (3) record the results of electrophysiological investigations.