Case Study 147 - Hemi-Facial Spasm Hemifacial spasm is a neuromuscular disorder that involves frequent contractions or spasms of the muscles on one side of the face. The spasms are involuntary, meaning they happen on their own without trying. The first symptom is usually twitching of the eyelid muscle that comes and goes. Eventually the spasms involve all of the muscles on one side of the face almost nonstop. Most often hemifacial spasm is caused by a blood vessel pressing on the facial nerve at