Tourette syndrome (TS) is a neurological disorder characterized by repetitive, stereotyped, involuntary movements and vocalizations called tics. The disorder is named for Dr. Georges Gilles de la Tourette, the pioneering French neurologist who in 1885 first described the condition in an 86-year-old French noblewoman.
The early symptoms of TS are almost always noticed first in childhood, with the average onset between the ages of 7 and 10 years. TS occurs in people from all ethnic groups; males are affected about three to four times more often than females. Although TS can be a chronic condition with symptoms lasting a lifetime, most people with the condition experience their worst symptoms in their early teens, with improvement occurring in the late teens and continuing into adulthood.
Tics are classified as either simple or complex. Simple motor tics are sudden, brief, repetitive movements that involve a limited number of muscle groups. Some of the more common simple tics include eye blinking and other vision irregularities, facial grimacing, shoulder shrugging, and head or shoulder jerking. Simple vocalizations might include repetitive throat-clearing, sniffing, or grunting sounds. Complex tics are distinct, coordinated patterns of movements involving several muscle groups. Complex motor tics might include facial grimacing combined with a head twist and a shoulder shrug. Other complex motor tics may actually appear purposeful, including sniffing or touching objects, hopping, jumping, bending, or twisting. Simple vocal tics may include throat-clearing, sniffing/snorting, grunting, or barking. More complex vocal tics include words or phrases. Perhaps the most dramatic and disabling tics include motor movements that result in self-harm such as punching oneself in the face or vocal tics including coprolalia (uttering swear words) or echolalia (repeating the words or phrases of others). Some tics are preceded by an urge or sensation in the affected muscle group, commonly called a premonitory urge. Some with TS will describe a need to complete a tic in a certain way or a certain number of times in order to relieve the urge or decrease the sensation.
Tics are often worse with excitement or anxiety and better during calm, focused activities. Certain physical experiences can trigger or worsen tics, for example tight collars may trigger neck tics, or hearing another person sniff or throat-clear may trigger similar sounds. Tics do not go away during sleep but are often significantly diminished.
Although the cause of TS is unknown, current research points to abnormalities in certain brain regions (including the basal ganglia, frontal lobes, and cortex), the circuits that interconnect these regions, and the neurotransmitters (dopamine, serotonin, and norepinephrine) responsible for communication among nerve cells. Given the often complex presentation of TS, the cause of the disorder is likely to be equally complex.
Many with TS experience additional neurobehavioral problems including inattention; hyperactivity and impulsivity (attention deficit hyperactivity disorder—ADHD) and related problems with reading, writing, and arithmetic; and obsessive-compulsive symptoms such as intrusive thoughts/worries and repetitive behaviors. For example, worries about dirt and germs may be associated with repetitive hand-washing, and concerns about bad things happening may be associated with ritualistic behaviors such as counting, repeating, or ordering and arranging. People with TS have also reported problems with depression or anxiety disorders, as well as other difficulties with living, that may or may not be directly related to TS. Given the range of potential complications, people with TS are best served by receiving medical care that provides a comprehensive treatment plan.
TS is a diagnosis that doctors make after verifying that the patient has had both motor and vocal tics for at least 1 year. The existence of other neurological or psychiatric conditions can also help doctors arrive at a diagnosis. Common tics are not often misdiagnosed by knowledgeable clinicians. But atypical symptoms or atypical presentation (for example, onset of symptoms in adulthood) may require specific specialty expertise for diagnosis. There are no blood or laboratory tests needed for diagnosis, but neuroimaging studies, such as magnetic resonance imaging (MRI), computerized tomography (CT), and electroencephalogram (EEG) scans, or certain blood tests may be used to rule out other conditions that might be confused with TS.
Because tic symptoms do not often cause impairment, the majority of people with TS require no medication for tic suppression. However, effective medications are available for those whose symptoms interfere with functioning. Neuroleptics are the most consistently useful medications for tic suppression; a number are available but some are more effective than others (for example, haloperidol and pimozide). Unfortunately, there is no one medication that is helpful to all people with TS, nor does any medication completely eliminate symptoms. In addition, all medications have side effects. Most neuroleptic side effects can be managed by initiating treatment slowly and reducing the dose when side effects occur. The most common side effects of neuroleptics include sedation, weight gain, and cognitive dulling. Neurological side effects such as tremor, dystonic reactions (twisting movements or postures), parkinsonian-like symptoms, and other dyskinetic (involuntary) movements are less common and are readily managed with dose reduction. Discontinuing neuroleptics after long-term use must be done slowly to avoid rebound increases in tics and withdrawal dyskinesias. One form of withdrawal dyskinesia called tardive dyskinesia is a movement disorder distinct from TS that may result from the chronic use of neuroleptics. The risk of this side effect can be reduced by using lower.
Psychotherapy may also be helpful. Although psychological problems do not cause TS, such problems may result from TS. Psychotherapy can help the person with TS better cope with the disorder and deal with the secondary social and emotional problems that sometimes occur. More recently, specific behavioral treatments that include awareness training and competing response training, such as voluntarily moving in response to a premonitory urge, have shown effectiveness in small controlled trials.
Evidence from twin and family studies suggests that TS is an inherited disorder. Although early family studies suggested an autosomal dominant mode of inheritance (an autosomal dominant disorder is one in which only one copy of the defective gene, inherited from one parent, is necessary to produce the disorder), more recent studies suggest that the pattern of inheritance is much more complex. The sex of the person also plays an important role in TS gene expression. At-risk males are more likely to have tics and at-risk females are more likely to have obsessive-compulsive symptoms.
People with TS may have genetic risks for other neurobehavioral disorders such as depression or substance abuse. Genetic counseling of individuals with TS should include a full review of all potentially hereditary conditions in the family.
Although there is no cure for TS, the condition in many individuals improves in the late teens and early 20s. As a result, some may actually become symptom-free or no longer need medication for tic suppression. Although the disorder is generally lifelong and chronic, it is not a degenerative condition. Individuals with TS have a normal life expectancy. TS does not impair intelligence. Although tic symptoms tend to decrease with age, it is possible that neurobehavioral disorders such as depression, panic attacks, mood swings, and antisocial behaviors can persist and cause impairment in adult life.
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