tic n : a local and habitual twitching especially in the face
- Rhymes: -ɪk
- A local and habitual convulsive motion of certain muscles.
A local and habitual convulsive motion of certain muscles
A tic is a sudden, repetitive, stereotyped, nonrhythmic movement (motor tic) or sound (phonic tic) that involves discrete groups of muscles. Tics can be invisible to the observer (e.g.; abdominal tensing or toe crunching). Movements of other movement disorders (e.g.; chorea, dystonia, myoclonus) must be distinguished from tics. Other conditions (e.g.; autism, stereotypic movement disorder) also include movements which may be confused with tics. Tics must also be distinguished from compulsions of OCD and seizure activity.
Description and classificationTics are classified as motor vs. phonic, and simple vs. complex.
Motor tics are movement-based tics affecting discrete muscle groups.
Phonic tics are involuntary sounds produced by moving air through the nose, mouth, or throat. They may be alternately referred to as verbal tics or vocal tics, but most diagnosticians prefer the term phonic tics to reflect the notion that the vocal cords are not involved in all tics that produce sound.
Tics may increase as a result of stress, tiredness, or high energy emotions, which can include negative emotions, such as anxiety, but positive emotions as well, such as excitement or anticipation. Relaxation may result in a tic decrease or a tic increase (for instance, watching television or using a computer), while concentration in an absorbing activity often leads to a decrease in tics. Neurologist and writer Oliver Sacks describes a physician with severe Tourette syndrome, (Canadian Mort Doran, M.D., a pilot and surgeon in real life, although a pseudonym was used in the book), whose tics remit almost completely while he is performing surgery.
Immediately preceding tic onset, most individuals are aware of an urge that is similar to the need to yawn, sneeze, blink, or scratch an itch. Individuals describe the need to tic as a buildup of tension which they consciously choose to release, as if they "had to do it". Examples of this premonitory urge are the feeling of having something in one's throat, or a localized discomfort in the shoulders, leading to the need to clear one's throat or shrug the shoulders. The actual tic may be felt as relieving this tension or sensation, similar to scratching an itch. Another example is blinking to relieve an uncomfortable sensation in the eye.
Tics are described as semi-voluntary or "unvoluntary", because they are not strictly involuntary—they may be experienced as a voluntary response to the unwanted, premonitory urge. A unique aspect of tics, relative to other movement disorders, is that they are suppressible yet irresistible; they are experienced as an irresistible urge that must eventually be expressed.
Complex tics are rarely seen in the absence of simple tics. Tics "may be challenging to differentiate from compulsions", as in the case of klazomania (compulsive shouting).
Tic disordersTic disorders occur along a spectrum, ranging from mild to more severe, and are classified according to duration and severity (transient tics, chronic tics, or Tourette syndrome). Tourette syndrome is the more severe expression of a spectrum of tic disorders, which are thought to be due to the same genetic vulnerability. Nevertheless, most cases of Tourette syndrome are not severe. Tics that begin after the age of 18 are generally not considered symptoms of Tourette's syndrome.
Tics must be distinguished from fasciculations. Small twitches of the upper or lower eyelid, for example, are not tics because they don't involve a whole muscle. They are twitches of a few muscle fibre bundles, which you can feel but barely see.
Society and cultureThere is some confusion in media portrayals of tics.
- Black, Kevin J. Tourette Syndrome and Other Tic Disorders.
- Evidente, GH. "Is it a tic or Tourette's? Clues for differentiating simple from more complex tic disorders." PostGraduate Medicine Online. October 2000 108:5.
- Swerdlow, NR. Tourette Syndrome: Current Controversies and the Battlefield Landscape. Curr Neurol Neurosci Rep. 2005, 5:329-331. PMID 16131414
- Tourette Syndrome Association. href="http://www.tsa-usa.org/what_is/whatists.html">http://www.tsa-usa.org/what_is/whatists.html What is Tourette syndrome? Accessed 24 May 2006.
tic in German: Tic
tic in Spanish: Tic
tic in French: Tic
tic in Hebrew: טיק
tic in Dutch: Tic
tic in Polish: Tik
tic in Portuguese: Tique
tic in Slovak: Tik
tic in Serbian: Тикови
tic in Swedish: Tics
tic in Russian: Нервный тик
abstraction, abulia, agitation, alienation, anxiety, anxiety equivalent, anxiety state, apathy, apprehensiveness, attack of nerves, bob, bobble, bounce, buck fever, bump, case of nerves, catatonic stupor, complex, compulsion, dejection, depression, detachment, didder, dither, elation, emotionalism, euphoria, excessive irritability, falter, fascination, fear, fidgetiness, fidgets, fixation, fixed idea, folie du doute, grimace, hang-up, hypercathexis, hypochondria, hysteria, hysterics, idee fixe, indifference, insensibility, irresistible impulse, jar, jerk, jig, jigget, jiggle, jog, joggle, jolt, jostle, lethargy, mania, melancholia, mental distress, monomania, morbid drive, morbid excitability, nerves, nervosity, nervous stomach, nervousness, obsession, obsessive compulsion, panic, panickiness, pathological indecisiveness, possession, preoccupation, prepossession, psychalgia, psychomotor disturbance, quake, quaver, quiver, rictus, ruling passion, shake, shiver, shock, shudder, spell of nerves, stage fright, state of nerves, stupor, tremble, tremor, trepidation, twitch, twitching, twitter, uneasiness, unresponsiveness, vellication, withdrawal, wobble