TIC

(from the 17th-century French tic or ticq, a twitching), a sudden rapid, recurring contraction in a muscle or group of muscles, occurring more often in the upper parts of the body. The movement is always brief, irresistible, and limited to one part of the body. It does not interfere with the use of the part involved and may be halted voluntarily, but only for a time. If the tic movement becomes ingrained, it is looked upon as a habit; the possessor becomes relatively unaware of its occurrence. Then a tic may be considered to be involuntary. These characteristics of tic help to differentiate it from other involuntary movements, such as spasm or cramp, or the capricious, uninhibitable movements that may occur in the afflictions chorea (St. Vitus' dance) or epilepsy. While most tics are probably of psychological origin, similar repetitive movements have been observed in physical disorders, as in the late stages of encephalitis. The movements that accompany brain disease may persist for years but tend to cease eventually. Nervous children between five and twelve years of age are those most likely to have tics, but no age group is immune. The movement appears when the subject is tense, and distraction will reduce it. The sufferer knows that he has a certain control of the movement but feels impelled to go through with it in order to feel better. According to psychoanalytic interpretation, tics are the involuntary motor expression of emotional activity, and they depend primarily upon the subject's early psychological and sexual development. Tics frequently involve the face and air passages. The most common tics are a repetitive grimace, blink, sniff, snort, or click in the nose or throat, a twitch, or a shrug. Tics occur in decreasing frequency from head to foot. Psychotherapy, relaxation training, and biofeedback training have had some success in treating tics.