Twitching may be a result of cell misfiring in certain parts of the brain, according to WebMD. An unvoluntary head tic or twitch does not have a determined medical cause, as of September 2014.
Head jerking is technically considered a tic, WebMD asserts. A complex motor tic is a series of unvoluntary movements that occur in the same order. A person with a head tic may be able to suppress the movement temporarily but can experience discomfort until the tic is performed. People of all ages can have tics, but they are most common in children. WebMD states that about 25 percent of children experience tics.