Hemifacial spasm (HFS) is a neurological disorder manifested by twitching on one side of the face due to involuntary contractions of the eyelid and other facial muscles. It usually begins gradually ...

Many of the most common and accepted explanations include sleep deprivation, dehydration, too much caffeine, stress, a pinched nerve, or as a side effect of medication. "Muscle spasms may also ...