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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.
2) Tourette Syndrome and Other Tic Disorders
4) Tourette Syndrome and Other Tic Disorders
6) Tourette's, Other Tic Disorders Far More Common Than Once Thought
7) Definition and Classification of Tic Disorders