Facial muscle spasm, also known as facial muscle twitching, hemifacial spasm, manifests as paroxysmal, rhythmic twitching, spasm or tonic seizure of one side of the facial muscles. The twitching mostly starts from the orbicularis oculi on one side and gradually expands downward to the orbicularis oris and facial expression muscles, causing facial pain in severe cases and affecting vision, speech and sleep. Causes Facial myoclonus may be caused by demyelination of the facial nerve from the brainstem due to compression of the abnormal vasculature of the vertebrobasilar system, resulting in short-circuiting of impulses between the afferent and efferent nerve fibers, leading to the occurrence of facial twitching. In addition, abnormally high excitability of the motor nucleus of the facial nerve caused by vascular compression may also be a cause of facial spasm. The spasm is intermittent at the beginning, but gradually becomes more frequent, and the symptoms can be aggravated by emotional stress and fatigue. 4. Physical examination shows no positive neurological signs other than facial twitching symptoms; 5.