| A rare primary myoclonus characterized by progressive, involuntary, irregular, clonic or tonic contractions of the muscles innervated by the facial nerve (cranial nerve VII). The symptoms are typically strictly unilateral, mostly persist during sleep, and often occur in the region of the orbicularis oculi muscle first and gradually spread to other parts of the affected half of the face as the disease progresses. Both familial and acquired forms are reported. |
