[Electronistagmographic characteristics of vestibular function and eyelids dystonia in patients with facial dyskinesias].

Electronistagmography has been performed in a vestibular function study of patients with facial dyskinesias - blepharospasm and facial hemispasm - before and after treatment with botulotoxin type A (dysport). A comparison groups included patients with myasthenia, functional dyskinesias, Greffe myodystrophy and healthy people. The method was applied for hyperkinesis objectification in patients with facial dyskinesias with the high amount of muscles artifacts caused by involuntary contractions of eye orbicular muscle. Ratio of the muscles artifact duration to the duration of investigation designated as the coefficient of eyelids dystonia period was determined. Blefarospasm symptoms were maximal during the gaze abduction and the direct gaze and minimal with eyes closed. The hyperkinesis caused disturbances of the visual-vestibular interaction during sinusoidal head rotations with the gaze fixation on the movable object, the appearance of deformed nystagmus waves with 2-peaks, the dysrhythmia and optokinetic nystagmus asymmetry. The disturbances mentioned above decreased or disappeared after the treatment with dysport. Vestibular disturbances were not revealed in other groups included in the study. The results of this study confirm the correlation between the hyperkinesis duration and the eyeballs position in blepharospasm and support evidence of the involvement of the peripheral factor in the pathogenesis of this disease.