Oculopalatal myoclonus.

Five cases of oculopalatal myoclonus (OPM) were studied. Three exhibited the lateral form, characterized by jerky nystagmoid eye movements with simultaneous oblique and rotatory components, associated with lateralized palatal myoclonus, and 2 the midline form, characterized by vertical to-and-fro pendular eye movements with symmetric bilateral palatal myoclonus. Structural studies using computed tomography (CT) and proton nuclear magnetic resonance (NMR) imaging indicated that the integrity of the flocculus was preserved in all 5 cases. We postulate that the generation of ocular oscillations in OPM involves vestibulo-ocular reflex (VOR) adaptation mediated by the flocculus. The lateral form represents unilateral disease, whereas the midline form represents bilateral disease.