Doctor's Notes on Tourette's Syndrome
Tourette syndrome (TS) is a neurological disorder associated with characteristic signs and symptoms. It is characterized by repetitive, stereotyped, involuntary movements and vocalizations called tics. The exact cause of Tourette syndrome is not well understood. Many people with Tourette syndrome experience additional neurobehavioral conditions such as attention deficit hyperactivity disorder (ADHD) or obsessive-compulsive symptoms.
The tics of Tourette syndrome are either simple or complex. Simple motor tics are sudden, brief, repetitive movements involving only a few muscle groups, such as eye blinking, head or shoulder jerking, or grimacing. Examples of simple vocal tics are repetitive throat-clearing, sniffing, or grunting sounds. Complex tics are coordinated patterns of movements involving several muscle groups, such as hopping or jumping. More complex vocal tics may include repetition of certain words or phrases.
Tourette's Syndrome Symptoms
The leading sign of Tourette's syndrome, and the most common reason for referral for consultation is the presence of tics. However, it is worthwhile to mention that even though tics might be disabling, they are not necessarily, as will be discussed later on, the most disabling problem in persons with Tourette's syndrome.
Tics are repetitive, involuntary or semi-voluntary, short lasting, stereotyped movements (motor tics) or vocalizations (phonic tics), of sudden presentation, usually in clusters. There are many clinical varieties of tics that can affect any part of the body, but they are more common in the face, trunk, and shoulders.
Traditionally, tics have been divided into two main groups:
- motor tics, and
- vocal tics.
The motor tics are described as simple motor tics when they involve a single muscle, or complex motor tics when they consist of a more coordinated movement resembling a normal function.
Similarly, the vocal tics can be simple vocal tics when they consist of simple sounds or complex when they consist in the production of words or sentences (complex phonic tics).
The following are examples of tics commonly seen in persons with Tourette's:
- Simple motor tics include:
- eye blinking,
- shoulder rotation or elevation,
- head jerking,
- lip contractions,
- closing of the eyes,
- eyes rolling in the orbits,
- torticollis (turning the neck to one side),
- opening and closing of the mouth,
- abdominal contractions, and/or
- stretching of arms and legs.
- Complex motor tics include:
- touching objects,
- trunk bending or rotation,
- socially inappropriate movements,
- obscene gestures, or
- imitation of other peoples' gestures.
- Simple phonic tics include:
- clearing throat,
- meaningless sounds or utterances.
- Complex phonic tics include:
- complex and loud sounds,
- phrases out of context,
- phrases with obscenities,
- repetition of other person's phrases.
Tics might be transiently suppressed by the individual. Additionally, tics may also be suppressed with tasks that require concentration or by distraction. For example, when a child with tics is watching TV or playing video games, the tics may be suppressed to a minimum. This characteristic could lead a non-informed observer to believe that the movements are fully under the child's control. However, this is not the case. Even though the patient has some control, prolonged suppression of tics is usually associated with an unpleasant sensation that is relieved only by the tic. Voluntary suppression of tics is a very taxing task for the person with Tourette's syndrome.
Most individuals with Tourette's syndrome perceive some inner body sensation before the tic occurs. For example, he/she may feel a burning or an itching of the eyes that is suppressed by moving the eyes, or a tickling in the throat that is relieved only by "clearing the throat". After this subjective feeling, the patient may need to repeat the tic several times until the unpleasant sensation is gone. In some individuals, a non-well defined urge precedes the tic.
Moreover, tics have a wax and wane quality. Tics have a tendency to cluster during certain hours and under certain circumstances rather than being present evenly throughout the day. Also, tics might not be seen for hours after a severe cluster.
Additionally, the quality, frequency, and type of tics change during the evolution of the disease. Tics that were once frequently seen are suppressed and exchanged for other tics.
Usually, the first signs of disease start in childhood. The tics may increase in frequency and severity in adolescence and, even though the condition is chronic, there is a tendency to improve in adulthood. By age 18, 50 % of patients with Tourette's syndrome might be symptom-free; however, some individuals might see a recurrence of the symptoms later in life. Usually, simple motor tics are seen at an early age and precede verbal tics. Also, complex tics are first seen later in life.
Other Associated Conditions
Associated conditions have been reported in almost half of the children with Tourette's syndrome. The most common is attention deficit hyperactivity disorder (ADHD) and obsessive compulsive disorder (OCD). Both of these disorders can be observed before school age. It is not clear why these conditions are so frequently present. It is probable that they share a common pathological mechanism in the brain.
In addition, individuals with Tourette's syndrome may also have depression, anxiety, and other behavioral problems. In some cases, this may be attributed to being perceived as different or being rejected by peers.
Developmental disability is not a feature of Tourette's syndrome, however, the presence of ADHD may disrupt learning, resulting in poor grades.
Tourette's Syndrome Causes
Our present understanding is that Tourette's syndrome is a biological disorder of the brain, but the exact reasons for of the tics and the associated disorders that are often seen in persons with Tourette's syndrome are not clear.
Fortunately, Tourette's syndrome is not a fatal condition; hence, there are very few possibilities of performing autopsies on individuals with Tourette's syndrome. In the few autopsies reported most of the abnormalities were seen in an area deep in the brain, the basal ganglia, which is known to be strongly associated with the control of movement. This is an expected finding since this area of the brain is known to be abnormal in other conditions that are also associated with movement disorders not related to Tourette's syndrome. Recently, MRI studies of the brain in persons with Tourette's syndrome also have shown some abnormalities in this area of the brain.
There is a familial incidence of Tourette's syndrome. First-degree relatives of persons with Tourette's syndrome more frequently have tics and obsessive compulsive disorders or attention deficit hyperactivity disorder (ADHD) than the general population. Also, twin studies have shown that identical twins (monozygotic twins) are five times more likely to both have Tourette's syndrome than in twins that are not identical (dizygotic twins). These observations suggest an autosomal dominant inheritance of the condition with variable penetrance.
However, in spite of this strong evidence of genetic involvement, at the present time, no gene has been identified as related to Tourette's syndrome. Moreover, other factors are certainly also responsible for the symptoms. For example, the severity of the syndrome in affected identical twins is not necessarily the same. For example, Tourette's syndrome is more severe in the twin who experienced greater perinatal complications.
The observation of tics developing after streptococcal infections motivated clinical trials to look at the role of autoimmune disorders as a cause of Tourette's syndrome. It is known that streptococcal infections can trigger, in certain individuals, autoimmune disorders that can attack and damage the basal ganglia, resulting in Sydenham chorea. This is a movement disorder characterized by multiple abnormal movements, including tics, as well as other behavioral issues such as obsessive compulsive disorders, which are also seen in people with Tourette's syndrome. Also clinical trials have looked at the role that pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) may play in the development and prognosis of Tourette's syndrome, but, presently, this is only a hypothesis and has not been proven.
Finally studies are inconclusive about the possible association between exposure to stimulants methylphenidate (Ritalin, Ritalin SR, Ritalin LA), amphetamines (Adderall) and certain other medications lamotrigine (Lamictal) and the precipitation of Tourette's syndrome.
It has also been found that Tourette's syndrome is more common in boys than in girls by a ratio of five to one.
Tourette's syndrome has been described in people of many ethnic backgrounds. At the present time there is no indication that Tourette's syndrome is more frequent in any particular ethnic group.
Attention deficit hyperactivity disorder (ADHD) is a disorder that affects behavior. A recent national study reported by the CDC noted that 11% of school aged children are being diagnosed with ADHD. Three main symptoms define ADHD including inattention, hyperactivity, and impulsivity. The symptoms are severe enough to affect the child's behavior in social situations and at school. The criteria for ADHD diagnosis were established in the Diagnostic and Statistical Manual of Mental Health (DSM-IV; American Psychiatric Association) in 1994. To be diagnosed with ADHD, a child must exhibit the symptoms outlined in this slideshow for at least six months.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.