Facial myokymia.

The facial musculature may be the site of a great variety of involuntary movements, often of doubtful nature and obscure causation. One form was sharply delineated both by clinical description and probable pathogenesis by Andermann, Cosgrove, LloydSmith, Gloor, and McNaughton (1961). These authors drew attention to the condition of facial myokymia of which they described four cases of their own and found seven reliable reports in the earlier literature. Of these 11 patients, eight almost certainly had disseminated sclerosis; in two this diagnosis seemed probable and in one the myokymia had been the only important symptom at the time of reporting. I have found no subsequent reports of this condition, which might therefore be thought to be exceedingly rare. It is in order to correct this impression that I here report seven episodes of myokymia occurring in five patients observed in the past six years. Unnecessary repetition in the case histories may be avoided by a general description of the salient and essentially stereotyped clinical features. In the five attacks where the myokymia was the only important symptom the onset was apparently abrupt, the day of onset of abnormal sensations being stated without hesitation. As far as I could determine the whole of the facial musculature on the affected side would be affected from the onset but I was not able to confirm this by personal observation. The onset of the other two attacks coincided with other more serious symptoms and the patients made no complaint of the facial movements. The usual complaint was that one side of the face felt 'screwed up' or 'swollen' and that certain movements were difficult to perform. There was no spontaneous complaint of weakness, movements seeming difficult because of 'stiffness' of the face. Three patients were aware of the flickering movements on the affected side and had observed these in the looking glass. The appearance of the face when the condition is fully developed is highly characteristic but, like many forms of involuntary movement, not easy to describe. All the muscles of one side of the face appear to be in slight contraction so that the palpebral fissure is narrowed, the angle of the mouth drawn up and the lips slightly pursed. Continuous 35 flickering can be seen in all the muscles from the frontalis to the platysma. This flickering is quite different from even the most severe fasciculation seen, for example, in the muscles of the upper limbs in motor neurone disease, as it is repeated with extraordinary rapidity. A highly characteristic feature is that the flickering passes over the face in rapid undulating waves, too fast and complex for visual analysis. In two patients I thought that there was slight weakness of the face on the affected side but in view of the mutually antagonistic action of many of the continuously contracting muscles this impression could well have been wrong. There was certainly no question of a marked facial palsy. The duration of the phenomenon was highly variable and not easy to assess exactly as usually the movements abated gradually. The condition would initially be obvious even to casual inspection but after a variable period would pass through successive phases in which the continuous contraction became less obvious and the flickering less frequent. Towards the end of an attack the movement might be confined to one or two muscles, particularly those of the lids, and eventually the patient would state that only occasional flickering was experienced and none could be seen during the examination. Of the seven attacks witnessed, the duration varied from three weeks to approximately six months. Associated symptoms possibly directly related to the disorder of the facial nerve were infrequent. One patient had noticed hyperacusis on the affected side for a period of three days some 12 days before the onset of myokymia. Sense of taste was not disturbed in any of the patients.