An involuntary non-rhythmic motor movement or vocal production which serves no apparent purpose. It may occur as the result of a neurological lesion, and most famously in Gilles de la Tourette syndrome, where the patient may suddenly utter a sound like a bark, or swear without provocation or intention to do so.
Not to be confused with Tick.A tic is a sudden, repetitive, stereotyped, nonrhythmic, involuntary movement (motor tic) or sound (phonic tic) that involves discrete groups of muscles.
Description and classification
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Tics are classified as motor vs.
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, vocal tics, or phonic tics, but some diagnosticians prefer the term phonic tics, to reflect the notion that the vocal cords are not involved in all tics that produce sound.
Simple tics
Simple motor tics are typically sudden, brief, meaningless movements, such as eye blinking or shoulder shrugging. Motor tics can be of an endless variety and may include such movements as hand-clapping, neck stretching, mouth movements, head, arm or leg jerks, and facial grimacing.
A simple phonic tic can be almost any possible sound or noise, with common vocal tics being throat clearing, coughing, sniffing, or grunting.
Complex tics
Complex motor tics are typically more purposeful-appearing and of a longer nature.
Complex tics are rarely seen in the absence of simple tics.
Typically, tics increase as a result of stress 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, tics may increase when one relaxes watching television), while concentration in an absorbing activity often leads to a decrease in tics.
Tic disorders
Tic 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).
Controversy and confusion
There is some confusion in media portrayals of tics.
Tics must be distinguished from fasciculations.
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