Tic
Motor tics are movement-based tics affecting discrete muscle groups.
Tic
Tics must also be distinguished from fasciculations. Small twitches of the upper or lower eyelid, for example, are not tics, because they do not involve a whole muscle. They are twitches of a few muscle fibre bundles, which can be felt but barely seen. Such eyelid twitches also differ from tics in that they are not suppressible, are strictly involuntary, and tend to fade after a day or two.