Hemifacial spasm (HFS) is a rare movement disorder that causes involuntary muscle contractions on one side of the face. It typically starts with painless but annoying twitching around one eye. Over ...

You’re relaxing on the sofa when suddenly your eyelid starts twitching. Or perhaps it’s a muscle in your arm, your leg, or your foot that begins to spasm – sometimes for a few seconds, sometimes for ...