What Is Tourette Syndrome? What Causes Tourette Syndrome?

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Main Category: Neurology / Neuroscience
Also Included In: Autism;  ADHD
Article Date: 04 Jan 2010 - 0:00 PDT

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Tourette syndrome, also known as Tourette's syndrome, GTS, Tourette's, TS, Tourette's disorder, or Gilles de la Tourette Syndrome, is an inherited tic disorder characterized by multiple motor (physical) tics and at least one vocal tic. Experts believe it is closely linked to damage or abnormalities to the basal ganglia of the brain.

In this text, a tic is an unusual movement or sound over which the person may have little or no control. This may include eye blinking, coughing, throat clearing, sniffing, facial movements, head movements, or limb movements. A tic may also include the utterance of unusual sounds, which may include inappropriate and sometimes offensive words (verbal ticks). Contrary to popular belief, only a small minority of people with Tourette's utter obscene words unintentionally.

Tourette's is part of a spectrum of tic disorders, including transient and chronic tics. The tics may emerge at any age, but do so most commonly between the ages of 6 and 18. They are more common among people with OCD (obsessive-compulsive disorder), an autistic spectrum disorder, or ADHD (attention deficit hyperactivity disorder).

For most people, the frequency and intensity of both minor and major tics tend to wax and wane (fluctuate). A person with Tourette syndrome may experience more frequent and possibly more intense tics when they have an infection, especially a strep (streptococcus) infections. Emotional and mental stress and distress may also exacerbate the tics.

The majority of people with Tourette's have normal intelligence and life expectancies. As the children pass through adolescence and early adulthood the severity of the tics tends to decrease. Extreme Tourette's in adulthood does exist, but it is rare.

According to The Mayo Clinic, USA, approximately 1% to 2% of the American population may have Tourette syndrome. It is much more common among males. The National Health Service, UK, estimates that approximately 1% of the UK population is affected by Tourette syndrome.

Georges Albest Edouard Brutus Gilles de la Tourette (1857-1904), a French physician and neurologist, was the first person to describe the condition and its symptoms. He published an account of nine patients in 1885. Jean Martin Charcot (1825-1893), a French neurologist and Professor of Anatomical Pathology bestowed the eponym "Tourette" on behalf of his resident.

According to Medilexicon's medical dictionary:

Tourette syndrome is "a tic disorder appearing in childhood, characterized by multiple motor tics and vocal tics present for longer than 1 year. Obsessive-compulsive behavior, attention-deficit disorder, and other psychiatric disorders may be associated; coprolalia and echolalia rarely occur; autosomal dominant inheritance."

What are the signs and symptoms of Tourette syndrome?

A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.

The hallmark sign of Tourette syndrome are tics, which can range from very mild to severe. Some severe tics can be extremely debilitating. A facial tic, such as eye blinking, may be the first sign. However, people may experience so many potential tics that there is not really a typical case (each person is different).

There are two types of tics:

• Physical tics (motor tics) - motor movements, such as blinking, jerking the head or any part of the body.
• Phonic tics (vocal tics) - uttering sounds, such as grunts or squeaks, and words or phrases.

There are two main classifications of ticks:

• Simple ticks - this may involve moving just one muscle, or uttering a single sound. Movements are sudden, short lived, and often repetitive.
• Complex ticks - the physical movements are more complex, and/or the phonic tics involve a more sophisticated set of utterances, including long phrases. Complex tics involve several muscle groups.

In many cases, a person with Tourette's will have a combination of phonic and physical tics, which may be simple or complex.

Examples of simple physical tics may include:

• Eye blinking
• Eye darting
• Grinding the teeth
• Head jerking
• Neck twisting
• Nose twitching
• Rolling the eyes
• Rotating the shoulders
• Shoulder shrugging
• Sticking the tongue out

Examples of simple phonic tics may include:

• Barking
• Blowing
• Clearing the throat
• Coughing
• Grunting
• Hiccupping
• Sniffing
• Squeaking
• Yelling and screaming

Examples of complex physical tics may include:

• Copropraxia - making obscene gestures
• Echopraxia - miming the movements of other people
• Flapping
• Head shaking
• Hitting things
• Jumping or hopping
• Kicking things
• Shaking
• Smelling objects
• Touching oneself
• Touching others

Examples of complex phonic tics include:

• Varying one's voice intonation
• Echolalia - repeating what other people say
• Paliphrasia - saying the same phrase over and over again
• Coprolalia - uttering or shouting obscene words or phrases

Advanced warning (premonitory sensations/feelings) - the majority of patients experience unusual or uncomfortable sensations before the onset of a tic. Examples include:

• The eyes have a burning feeling which is eventually only alleviated by blinking.
• A gradually growing muscle tension which can only be alleviated by stretching or twitching.
• The throat starts feeling dry. This sensation is only alleviated by grunting or clearing the throat.
• A limb or joint becomes itchy; the only relief is achieved by twisting it.

The following situations may cause tics to be worse:

• Anxiety and/or stress
• Fatigue (tiredness)
• Illness (especially a streptococcus infection)
• Excitement
• A recent head injury

The following situations may help improve tics:

• Engaging in competitive sports (in some cases, however, overexcitement may bring on tics)
• Playing an enjoyable computer game which involves a high level of concentration (in some cases, however, overexcitement may cause tics)
• Reading an interesting book
• Acquiring relaxation techniques

Most people can eventually hold the ticks back when they are in public view, such as classrooms. However, the longer they are held back, the harder it becomes. It is not uncommon for schoolchildren to suddenly release tics when they get home from school.

Over time the frequency and severity of tics may vary. A person with Tourette's may develop different tics over time. Experts say that during the teenage years tics tend to be at their worst. In many cases they improve during early adulthood.

What are the risk factors for Tourette syndrome?

A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2.

The following factors may increase the risk of developing Tourette's:

• Genetics - if a close relative, such as a sibling or parent has Tourette's, that person's risk of developing it is significantly higher, compared to other people.
• Premature birth - babies who are born prematurely have a higher risk of developing Tourette's.

What are the causes of Tourette syndrome?

Experts are not exactly sure what the cause is. However, available evidence indicates that the problem is probably in the basal ganglia.

• The basal ganglia - this is a group of specialized brain cells deep inside the brain. Basal refers to "the basement of the brain". The basal ganglia consists of three clusters of neurons - the caudate nucleus, putamen, and the globus pallidus - located at the base of the brain. The basal ganglia are responsible for involuntary movements, emotion and learning. The basal ganglia are abnormal in patients with Parkinson disease, Huntington disease, and a number of important neurologic conditions.
  
  MRI (magnetic resonance imaging) scans have revealed that the structure of the basal ganglia is different in patients with Tourette's. Experts believe that these abnormalities cause an imbalance in brain neurotransmitter levels. Neurotransmitters are messengers of neurologic information from one cell to another - they are messenger chemicals that transmit data between brain cells. Abnormal neurotransmitter levels may disrupt normal brain function, resulting in tics.
• Childhood infection - recent preliminary research indicates there might be a link between the development of tics and infection. The "theory" is that a childhood streptococcal infection may cause the child's immune system to produce antibodies which interact with brain tissue, affecting normal brain development. This theory remains controversial, and many Tourette experts do not accept it.

Diagnosing Tourette syndrome

There is no current test that can diagnose Tourette's. The health care professional relies on the patient's signs and symptoms, medical history, and family history.

Ruling out any other condition - the doctor needs to rule out the following conditions which may cause similar symptoms:

• Allergies - if the patient coughs or sniffs
• Dystonia - a neurological condition which includes involuntary movements and prolonged muscle contraction; the patient experiences twisting body motions, abnormal posture and tremor.
• Restless leg syndrome - if the patient has leg movements
• Vision - if the patient blinks a lot

The doctor may also order the following tests in order to rule out other medical conditions or illnesses:

• Blood test
• Eye test
• Imaging test - either MRI (magnetic resonance imaging) or CT (computerized tomography) scans
• Skin prick test (for allergies)

The patient needs to meet criteria spelled out in the Diagnostic and Statistical Manual of Mental Disorders (DSM); a manual published by the American Psychiatric Association. The criteria to diagnose Tourette's must include:

• Presence of both motor and vocal tics
• Tics occur several times a day, nearly every day or intermittently. These tics have been occurring for over one year.
• There must be no remission that lasts over three months.
• Tics start before the patient is 18 years old.
• Other possible causes have been ruled out, such as medications, other substances, or another medical condition.

If families and even health care professionals are unfamiliar with the signs and symptoms of Tourette, diagnosis is sometimes delayed. Parents and doctors may put blinking or sniffing down to vision or allergy problems.

What are the treatment options for Tourette syndrome?

A patient with Tourette's has the following treatment options - medication, non-pharmacological treatments, or surgery (rare, only when other treatments have failed) - some of which may be taken in combination:

Medication - this may include antihypertensives, muscle relaxants or neuroleptics. Antihypertensives and/or muscle relaxants are usually prescribed for patients with mild to moderate symptoms, while neuroleptics are more commonly given to those with moderate to severe symptoms.

• Antihypertensives - this type of medication is used for controlling high blood pressure (hypertension). However, they have been shown to help patients with mild to moderate symptoms of Tourette's. Experts believe that this type of medication helps regulate neurotransmitter levels. An example of such a medication is Clonidine.
  
  Side effects may include:
  
  
  • Constipation
  • Diarrhea
  • Dizziness
  • Dry mouth
  • Headaches
  • Sleepiness (drowsiness)
  • Tiredness
• Muscle relaxants - is used to overcome spasticity (when muscles become too stiff). They have been shown to help control physical tics. Examples include baclofen and clonazepam. Patients taking muscle relaxants should not consume alcohol.
  
  Side effects may include:
  
  
  • Drowsiness
  • Dizziness
  • Less alertness (if so, avoid driving or operating heavy machinery)
• Neuroleptics - this type of medication blocks the effects of dopamine on the brain. There are two main types of neuroleptics:
  
  
  • Typical neuroleptics - developed during the 1950s. The first generation of neuroleptics.
  • Atypical neuroleptics - developed during the 1990s. A newer generation.
  Atypical neuroleptics have less potential to cause side effects, hence they are usually recommended. Some patients may not be suitable candidates for atypical neuroleptics therapy. The medication is taken orally or as an injection. Some slow release neuroleptics only need to be injected once every two to six weeks.
  
  Typical neuroleptics side effects may include:
  
  
  • Blurred vision
  • Constipation
  • Drowsiness
  • Dry mouth
  • Lack of libido (sex drive)
  • Shaking
  • Spasms
  • Trembling
  • Twitches (muscles)
  • Weight gain
  
  Atypical neuroleptics side effects may include:
  
  
  • Blurred vision
  • Constipation
  • Dry mouth
  • Lack of libido
  • Weight gain
  
  If side effects are becoming a problem the patients should tell their doctor. There may be other neuroleptics they could take.

Non-pharmacological treatments

• Behavioral therapy - commonly used to help people with Tourette's. This type of therapy aims to change the pattern of the patient's behavior.
  
  
  Habit reversal is a type of behavior therapy that has been shown to be especially effective. According to the National Health Service (NHS), UK, it is based on two main principles:
  
  
  • Tourette syndrome patients are unaware of their tics
  • Tics are used to alleviate uncomfortable sensations before they occur
  The therapist helps the patient monitor the pattern and frequency of their tics. Any sensations that are triggering the tics are also identified.
  
  An alternative and less noticeable way of relieving the premonitory sensations are sought. This alternative response (rather than a tic) is called a competing response. For example, if an unpleasant sensation in the throat is a prelude to grunts or throat clearing noises, the patient learns to alleviate the sensation by taking a series of deep breaths.
  
  Habit reversal therapy often includes relaxation therapy. Stress or anxiety may exacerbate the severity and frequency of tics. Techniques, such as deep breathing or visualization may help relieve anxiety, often resulting in fewer and less severe tics.

Acupuncture and hypnosis are other possible therapies for Tourette's.

Surgery

Surgery is usually only considered for adult patients with severe symptoms who have not responded well to other treatments.

• Limbic leucotomy - an electric current or pulse of radiation is used to burn away a small part of the limbic system. The limbic system is responsible for our higher emotions, behavior and memory. A limbic leucotomy often allows the surgeon to re-wire the brain, partially or completely resolving the patient's condition.
• Deep brain stimulation (DBS) - electrodes are implanted into parts of the brain known to be linked to Tourette's. The electrodes stay in there. They are connected to small generators which are also implanted inside the patient's body. An electronic pulse is sent from the generator to the electrodes, stimulating different parts of the brain, often controlling the symptoms of Tourette's.
  
  According to the National Health Service (NHS), UK, although initial DBS results have been encouraging, we do not know about the long-term safety and effectiveness of this relative new therapy. In most cases, access to DBS is through clinical trials.

What are the possible complications of Tourette syndrome?

Although Tourette's itself does not generally affect a person's intelligence, it can cause learning difficulties. As the condition often accompanies ADHD (attention deficit hyperactivity disorder), OCD (obsessive compulsive disorder) and autistic spectrum disorders, learning difficulties are common.

The basal ganglia, part of the brain most linked to Tourette's, is also involved in controlling habit learning. Hence, people with Tourette's commonly have problems learning through habit. Children may have difficulties mastering skills and activities which other children pick up rapidly, such as writing, reading or simple arithmetic.

A child with Tourette's may need additional specialized educational help.

Written by Christian Nordqvist


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