Biology 202
2002 First Paper
On Serendip

Is it possible to differentiate Tourette tics from non-Tourette tics? Are all tics the same? What is a tic? What does a tic feel like? How does "ticcing" affect a person's sense of self or "I-Function"? Are Tic Disorders Inherited?

A tic is a repetitive, uncontrollable, purposeless contraction of an individual muscle or group of muscles, usually in the face, arms, or shoulders. These movements may be signs of a minor psychological disturbance. Such tics often occur in childhood and will probably be outgrown. There are also tics that are caused by neurological disorders that could have resulted from brain damage at birth, head trauma, or use of some specific medication (1). Tic disorders may be inherited. Genetic analysis of numerous pairs of siblings has shown several areas that may contain genes that, when mutated, may give rise, or increase susceptibility to, Tourette Syndrome. There is growing evidence that Tourette Syndrome is inherited from both parents (bilineal transmission), with the father typically affected by childhood tics and the mother typically having some symptoms of obsessive-compulsive disorder (8). Tics can present as motor or vocal and are categorized as Simple or Complex (3) according to age of onset, duration and severity of symptoms (2). There are several different categories of tic disorders.

Transient tic disorders can begin during the early childhood years and can occur in up to 18% of all children. Simple transient motor tics can present in the form of eye blinking, nose scrunching, grimacing and squinting, and other forms (2). Simple transient vocal tics are less common and include sounds repeatedly made such as clearing the throat, coughing, grunting, hiccuping, belching, and other sounds. Transient tics last for a short while, only several weeks or months, and are usually not associated with specific behavioral problems. These tics are more noticeable during stressful, fatiguing or emotional times (2). Boys are three to four times more likely to be affected than girls. Transient tics usually do not last for more than one year, although it is not uncommon to have these episodes over the course of several years. For many children, the symptoms never go beyond blinking and sniffing (or similar choices) and are often described as "nervous habits" or allergy symptoms.

Chronic tic disorders are differentiated from transient tic disorders in that their duration is over many years and the behavior is unchanging. With transient tic disorder, the tic may change from one type to another, (sniffing may be replaced by forehead furrowing and then the furrowing is replaced by finger snapping), while in chronic tic disorder the tic remains the same for a very long time.

Chronic multiple tics present often, and in series. Sometimes it is difficult to draw distinctions between transient, chronic and chronic multiple tics (2).

Tourette Syndrome (TS), first described by Gilles de la Tourette, can be the most debilitating of the tic disorders and is characterized by multiform, frequently changing motor and vocal or phonic tics. There are multiple diagnostic criteria, as defined in the Diagnostic and Statistical Manual of Mental Disorders IV.

A. In Tourette Syndrome, both multiple motor and vocal tics have been present at some time during the illness, although not necessarily concurrently.

B. The tics occur many times a day (usually in bouts), nearly every day or intermittently throughout a period of more than 1 year, and during this period there was never a tic-free period of more than 3 consecutive months.

C. The disturbance causes marked distress or significant impairment in social, occupational, or other important areas of functioning.

D. The onset is before age 18.

E. The disturbance is not due to the direct physiological effects of a substance (e.g. stimulants) or a general medical condition (e.g. Huntington's disease or post-viral encephalitis) (2).

In Simple Motor tics, the movement is fast, darting and meaningless. In Complex Motor tics, the movement is slower and may appear purposeful (2). This form may include copropraxia (making obscene gestures), and echopraxia (mimicking movements that others make) (3). In Simple Vocal tics, the sound production contains meaningless noises. In Complex Vocal tics, there are linguistically meaningful words and phrases, including coprolalia (vocalizing obscene or other socially unacceptable words or phrases), echolalia (repeating what someone else has just said), and palilalia (repeating your own words over and over again) (3).

Tourette Syndrome is a spectrum disorder-it varies with each individual and may appear anywhere on the spectrum between very mild and severe (4). It does not affect intelligence, although in Tourette Syndrome the child may develop such additional behavioral and developmental disorders as Attention Deficit Hyperactivity Disorder, impulsivity, aggressivity, self-injurious behaviors, and varied learning disabilities (2).

When a person is engaged in tic behavior, what does he/she feel? A tic comes on the way a sneeze or a blink comes on; there i s a need to complete the act. Tics are involuntary and compelling, and the person has little control over the onset of the tic. Some individuals have reported that they are conscious of the urge to tic before the action occurs (3). The person is fleetingly aware that there is a flashing thought (I-Function or consciousness) which manifests in the tic behavior. I-Function can also be part of unconscious behavior. The motor and/or vocal response that began as an unconscious thought brought awareness during the tic event. If I-Function serves as a filter of both consciousness and unconsciousness, then the tic behavior has been filtered before and during the behavior. Almost simultaneously, the thought and action occur. A tic can be "put off" temporarily, but later, when the person permits him/herself to complete the urge to tic, the ticcing may increase in intensity.

Tics increase in frequency and severity with stress, during relaxation after physical exercise, idleness, fatigue, exposure to heat, and use of dopaminergic drugs, such as steroids, caffeine, and CNS stimulants. Tics usually diminish with performance of engaging mental or physical activities (e.g., playing computer games, playing sports) or with consumption of marijuana, alcohol or nicotine (5). Some people can control the tic urges so that they only tic in the privacy of a safe place, such as their home (4).

Tic disorders challenge individuals because they must develop a sense of self, ("I-Function"), something besides being a person who has a tic disorder. Children must cope with the embarrassment of tic disorders (whether the cause is Tourette Syndrome or a milder tic disorder). They are challenged every day in school settings; their friendships are tested because their behavior is different. Even under the best of circumstances, children have social problems, but with tic disorders, children have a particularly difficult time, often being shunned by playmates and peers. Children will develop this sense of self, this "I-Function," but while the personality is developing they must make choices about how they view themselves. Without a good support system, the child could become depressed and self-loathing, thinking of him/herself only as a person who tics. Without an "I-Function," the body is simply discharging neurological output.

Adults with tic disorders have similar issues, but have the advantage of life experience. They are lawyers and teachers, doctors and artists, plumbers and nurses, mothers and fathers. A person with a tic disorder needs to have a "split personality," in essence two "I-Functions" that can differentiate between the tic disorder and the "other" self. One needs to be able to harmonize the tic behavior into the "I-Function," allowing the behavior to become a part of the individual, rather than having tic behavior that is merely neurological output. The "I-Function" will be the determining factor that distinguishes one person with this disorder from another. An individual's perception of him/herself will greatly predict how successful he/she feels in the company of other people. "I-Function" is that which gives a person a sense of self, whether the I-Function is conscious or unconscious.

No matter what label is given to the tic disorder, the tic probably signifies a subtle brain developmental disorder. Researchers have linked Tourette Syndrome to an area of the brain known as the basil ganglia, which is involved in controlling movement and which plays an important role in attention, concentration, and decision making (6). Tic disorders involve abnormalities in the Central Nervous System levels of neurotransmitters or neuro-peptides, particularly dopamine, norepinephrine, opioid peptides, and serotonin (5). It has been observed that dopamine-blocking agents suppress tics in some individuals (8).

All tics are movements or sounds that occur intermittently and unpredictably out of a background of normal motor activity. Some tics are the result of brain injury, head trauma, or encephalitis, although most tics are commonly called idiopathic, and are part of the spectrum, which includes Gilles de la Tourette Syndrome, or one of the other idiopathic tic disorders (7). Many people now believe that all tic disorders are closely related and are perhaps all part of the same spectrum (4).

The differentiation of Tourette Syndrome tics from other tics may be no more than semantic, a somewhat arbitrary assignment to a category. Furthermore, recent genetic evidence links Tourette Syndrome with multiple and transient tics of childhood; Tourette Syndrome, therefore, can only be differentiated in retrospect (2).

I heard Dr. Oliver Sacks speak on this subject a few years ago and I remember something quite poignant. He said that he had no knowledge of Tourette Syndrome until he was presented with a patient who had this disorder. After that, he saw people with tic disorders everywhere he went. I know several people with tic behavior; I never had a name for the disorder.

References

WWW Sources

2) Tourette Syndrome and Other Tic Disorders

3) Tourette Syndrome:Tics

4) Tourette Syndrome and Other Tic Disorders

5) Is it a tic or Tourette's?

6) Tourette's, Other Tic Disorders Far More Common Than Once Thought

7) Definition and Classification of Tic Disorders

8) We Move: Tourette Syndrome

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