- A repetitive movement that is difficult, if not impossible, to control. Tics can affect any group of muscles. The most common are facial tics, such as eye- blinking, nose-twitching, or grimacing. Tics that affect the muscles used to produce speech are known as vocal tics, and can range from grunts or whistles to the repetition of complete words or phrases. Complex motor tics involve multiple, sequenced movements, and can include behaviors such as twirling in place, tapping a certain number of times, or stooping to touch the ground. Tics are believed to arise in differences in or damage to the basal ganglia, a structure deep within the brain that controls automatic movements and that also affects impulsivity.
* * *Habitual, repeated contraction of certain muscles, resulting in stereotyped individualized actions that can be voluntarily suppressed for only brief periods, e.g., clearing the throat, sniffing, pursing the lips, excessive blinking; especially prominent when the person is under stress; there is no known pathologic substrate. SEE ALSO: spasm. SYN: Brissaud disease, habit chorea, habit spasm. [Fr.]- t. de pensée a rarely used term for the habit of involuntarily giving expression to any thought that comes to mind. [Fr. of thought]- t. douloureux SYN: trigeminal neuralgia. [Fr. painful]- facial t. involuntary twitching of the facial muscles, sometimes unilateral. SYN: Bell spasm, convulsive t., facial spasm, palmus (1).- habit t. a habitual repetition of some grimace, shrug of the shoulder, twisting or jerking of the head, or the like.- rotatory t. SYN: spasmodic torticollis.- spasmodic t. a disorder in which sudden spasmodic coordinated movements of certain muscles or groups of physiologically related muscles occur at irregular intervals. SYN: Henoch chorea.* * *total ion current; Toxicology Information Center; trypsin inhibitory capability; tubulointerstitial cell; tumor- inducing complex
* * *tic 'tik n1) local and habitual spasmodic motion of particular muscles esp. of the face: TWITCHING2) a habitual usu. unconscious quirk of behavior or speech
* * *n.a repeated and largely involuntary movement varying in complexity from the twitch of a muscle to elaborate well-coordinated actions. Simple tics occur in about a quarter of all children and usually disappear within a year. Tics most often become prominent when the individual is exposed to emotional stress. See also Gilles de la Tourette syndrome.
* * *(tik) (Fr. tēk) [Fr.] an involuntary, compulsive, rapid, repetitive, stereotyped movement or vocalization, experienced as irresistible although it can be suppressed for some length of time; occurrence is exacerbated by stress and diminished during sleep or engrossing activities. Tics may be psychogenic or neurogenic in origin and are subclassified as either simple, such as eye blinking, shoulder shrugging, coughing, grunting, snorting, or barking, or complex, such as facial gestures, grooming motions, coprolalia, echolalia, or echokinesis.
Medical dictionary. 2011.