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'''Tourette syndrome''' (also called '''Tourette's syndrome''', '''Tourette's disorder''', '''Gilles de la Tourette syndrome''', '''GTS''' or the more common '''Tourette's''' or '''TS''') is an [[heredity|inherited]] [[neurological]] disorder with onset in [[child|childhood]], characterized by the presence of multiple physical (motor) [[tic]]s and at least one vocal (phonic) tic, which usually wax and wane. Tourette syndrome is defined as part of a [[spectrum]] of [[tic disorder]]s, which includes transient tics and chronic tics.
'''Tourette syndrome''' (also called '''Tourette's syndrome''', '''Tourette's disorder''', '''Gilles de la Tourette syndrome''', '''GTS''' or the more common '''Tourette's''' or '''TS''') is an [[heredity|inherited]] [[neurological]] disorder with onset in [[child|childhood]], characterized by the presence of multiple physical (motor) [[tic]]s and at least one vocal (phonic) tic, which usually wax and wane. Tourette syndrome is defined as part of a [[spectrum]] of [[tic disorder]]s, which includes transient tics and chronic tics.


Tourette syndrome was once considered a rare and bizarre [[syndrome]], most often associated with the sufferer uttering obscene words or socially inappropriate and derogatory remarks ([[coprolalia]]). However, this symptom is present in fewer than 15% of persons with Tourette's. Furthermore, it is no longer considered a rare condition, but it may not always be identified because of the wide range of severity, with most cases classified as mild. The precise cause of Tourette syndrome is not known, but [[genetics|genetic]] and [[environmental]] factors each play a role.
Tourette syndrome was once considered a rare and bizarre [[syndrome]], most often associated with the exclamation of obscene words or socially inappropriate and derogatory remarks ([[coprolalia]]). However, this symptom is present in fewer than 15% of persons with Tourette's. Furthermore, it is no longer considered a rare condition, but it may not always be identified because of the wide range of severity, with most cases classified as mild. The precise cause of Tourette syndrome is not known, but [[genetics|genetic]] and [[environmental]] factors each play a role.


People with Tourette's have normal [[life expectancy]] and [[intelligence quotient|intelligence]]. Notable individuals with Tourette syndrome are found across many professions and in all walks of life. The severity of the tics decreases for most children as they pass through [[adolescence]], and extreme Tourette's in adulthood is a rarity. [[Medication]] is not needed for most cases. Although no medication is effective for all persons with tics, there are medications and [[therapy|therapies]] that can help when their use is warranted. Understanding, knowledge about the condition, and a supportive family and community are the best treatments.
People with Tourette's have normal [[life expectancy]] and [[intelligence quotient|intelligence]]. Notable individuals with Tourette syndrome are found across many professions and in all walks of life. The severity of the tics decreases for most children as they pass through [[adolescence]], and extreme Tourette's in adulthood is a rarity. [[Medication]] is not needed for most cases. Although no medication is effective for all persons with tics, there are medications and [[therapy|therapies]] that can help when their use is warranted. Understanding, knowledge about the condition, and a supportive family and community are the best treatments.
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Tics are described as semi-voluntary or ''"unvoluntary",''<ref name=TSADef>Tourette Syndrome Association. [http://web.archive.org/web/20050322170245/http://www.tsa-usa.org/research/definitions.html Definitions and Classification of Tic Disorders.] Accessed 22 Mar 2005.</ref> because they are not strictly ''involuntary'': they may be experienced as a ''voluntary'' response to an unwanted, premonitory urge. Tics are experienced as irresistible and must eventually be expressed.<ref name=TSADef/> People with Tourette syndrome are sometimes able to suppress their tics to some extent for limited periods of time, but doing so often results in an explosion of tics afterward.<ref name=Zinner/> People with Tourette syndrome may seek a secluded spot to release their symptoms after suppressing them in school or at work. Some people with Tourette syndrome may not be aware of the premonitory urge. Children may be less aware of the premonitory urge associated with tics than are adults, but their awareness tends to increase with maturity.<ref name=TSADef/> They may have tics for several years before becoming aware of premonitory urges. Children may suppress tics while in the doctor's office, so they may need to be observed while they are not aware they are being watched.<ref name=Zinner/> The ability to suppress tics varies among individuals, and may be more developed in adults than children.
Tics are described as semi-voluntary or ''"unvoluntary",''<ref name=TSADef>Tourette Syndrome Association. [http://web.archive.org/web/20050322170245/http://www.tsa-usa.org/research/definitions.html Definitions and Classification of Tic Disorders.] Accessed 22 Mar 2005.</ref> because they are not strictly ''involuntary'': they may be experienced as a ''voluntary'' response to an unwanted, premonitory urge. Tics are experienced as irresistible and must eventually be expressed.<ref name=TSADef/> People with Tourette syndrome are sometimes able to suppress their tics to some extent for limited periods of time, but doing so often results in an explosion of tics afterward.<ref name=Zinner/> People with Tourette syndrome may seek a secluded spot to release their symptoms after suppressing them in school or at work. Some people with Tourette syndrome may not be aware of the premonitory urge. Children may be less aware of the premonitory urge associated with tics than are adults, but their awareness tends to increase with maturity.<ref name=TSADef/> They may have tics for several years before becoming aware of premonitory urges. Children may suppress tics while in the doctor's office, so they may need to be observed while they are not aware they are being watched.<ref name=Zinner/> The ability to suppress tics varies among individuals, and may be more developed in adults than children.


Although there is no such thing as a "typical" case of Tourette syndrome,<ref name=Zinner/> the condition follows a fairly reliable course in terms of age of onset and the natural time course of severity of symptoms. Tics may appear up to the age of 18, but the most typical age of onset is five to seven.<ref name=phenomenology/> The ages of statistical highest tic severity are 8 to 12 (average 10), with tics steadily declining for most patients as they pass through adolescence.<ref name=YaleTicSeverity>Leckman JF, Zhang H, Vitale A, et al. Course of tic severity in Tourette syndrome: the first two decades. ''Pediatrics''. 1998;102 (1 Pt 1):14-19. PMID 9651407 p. 14. [http://childpsych.columbia.edu/brainimaging/PDF/PD10298.pdf Full-text PDF.]</ref> The most common, first-presenting tics are eye blinking, facial movements, sniffing and throat clearing. Initially, tics are most frequent in midline body regions where there are many muscles, usually the head, neck and facial region.<ref name=Zinner/> This can be contrasted with the stereotyped movements of other disorders (such as [[stimming|stim]]s and [[stereotypy|stereotypies]] of the [[autism spectrum disorder]]s) which typically have an earlier age of onset, are more symmetrical, rhythmical, bilateral, and involve extremities (e.g.; flapping hands).<ref name=Rapin>Rapin I. Autism spectrum disorders: relevance to Tourette syndrome. ''Adv Neurol.'' 2001;85:89-101. PMID 11530449</ref> Tics appearing early in the course of the condition are frequently confused with other conditions such as [[allergies]], [[asthma]], and [[vision]] problems: pediatricians, allergists, and ophthalmologists are typically first to see a child with tics.<ref name=phenomenology/>
Although there is no such thing as a "typical" case of Tourette syndrome,<ref name=Zinner/> the condition follows a fairly reliable course in terms of age of onset and the natural time course of severity of symptoms. Tics may appear up to the age of 18, but the most typical age of onset is five to seven.<ref name=phenomenology/> The ages of statistical highest tic severity are 8 to 12 (average 10), with tics steadily declining for most patients as they pass through adolescence.<ref name=YaleTicSeverity>Leckman JF, Zhang H, Vitale A, et al. Course of tic severity in Tourette syndrome: the first two decades. ''Pediatrics''. 1998;102 (1 Pt 1):14-19. PMID 9651407 p. 14. [http://childpsych.columbia.edu/brainimaging/PDF/PD10298.pdf Full-text PDF.]</ref> The most common, first-presenting tics are eye blinking, facial movements, sniffing and throat clearing. Initial tics are most frequent in midline body regions where there are many muscles, usually the head, neck and facial region.<ref name=Zinner/> This can be contrasted with the stereotyped movements of other disorders (such as [[stimming|stim]]s and [[stereotypy|stereotypies]] of the [[autism spectrum disorder]]s) which typically have an earlier age of onset, are more symmetrical, rhythmical, bilateral, and involve extremities (e.g.; flapping hands).<ref name=Rapin>Rapin I. Autism spectrum disorders: relevance to Tourette syndrome. ''Adv Neurol.'' 2001;85:89-101. PMID 11530449</ref> Tics appearing early in the course of the condition are frequently confused with other conditions such as [[allergies]], [[asthma]], and [[vision]] problems: pediatricians, allergists, and ophthalmologists are typically first to see a child with tics.<ref name=phenomenology/>


Among patients whose symptoms are severe enough to warrant referral to clinics, [[obsessive-compulsive disorder]] (OCD) and [[attention-deficit hyperactivity disorder]] (ADHD) are often associated with Tourette's. Not all persons with Tourette syndrome will have ADHD or OCD, although in clinical populations, a high percentage of patients presenting for care do have ADHD.<ref name=Bagheri/> Approximately 40% of patients with Tourette syndrome have "TS-only" or "pure TS", referring to Tourette syndrome in the absence of ADHD, OCD or other disorders.<ref name=Denckla>Denckla MB. Attention deficit hyperactivity disorder: the childhood co-morbidity that most influences the disability burden in Tourette syndrome. ''Adv Neurol.'' 2006;99:17-21. PMID 16536349</ref>
Among patients whose symptoms are severe enough to warrant referral to clinics, [[obsessive-compulsive disorder]] (OCD) and [[attention-deficit hyperactivity disorder]] (ADHD) are often associated with Tourette's. Not all persons with Tourette syndrome will have ADHD or OCD, although in clinical populations, a high percentage of patients presenting for care do have ADHD.<ref name=Bagheri/> Approximately 40% of patients with Tourette syndrome have "TS-only" or "pure TS", referring to Tourette syndrome in the absence of ADHD, OCD or other disorders.<ref name=Denckla>Denckla MB. Attention deficit hyperactivity disorder: the childhood co-morbidity that most influences the disability burden in Tourette syndrome. ''Adv Neurol.'' 2006;99:17-21. PMID 16536349</ref>
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<ref>Moriarty J, Varma AR, et al. A volumetric MRI study of Gilles de la Tourette's syndrome. ''Neurology''. 1997;49:410-5. PMID 9270569</ref>
<ref>Moriarty J, Varma AR, et al. A volumetric MRI study of Gilles de la Tourette's syndrome. ''Neurology''. 1997;49:410-5. PMID 9270569</ref>


Some forms of OCD may be genetically linked to Tourette's:<ref>Pauls DL, Towbin KE, Leckman JF, et al. Gilles de la Tourette's syndrome and obsessive-compulsive disorder. Evidence supporting a genetic relationship. ''Arch Gen Psychiatry''. 1986 Dec;43(12):1180-2. PMID 3465280</ref> At least some forms of OCD are [[etiologic|etiologically]] related to Tourette syndrome and may, be a different expression of the same factors that are important for the expression of tics."<ref>Miguel EC, do Rosario-Campos MC, Shavitt RG, et al. The tic-related obsessive-compulsive disorder phenotype and treatment implications. ''Adv Neurol.'' 2001;85:43-55. PMID 11530446</ref> However, the genetic relationship of ADHD to Tourette syndrome has not been fully established.<ref name=Denckla>Denckla MB. Attention deficit hyperactivity disorder: the childhood co-morbidity that most influences the disability burden in Tourette syndrome. ''Adv Neurol.'' 2006;99:17-21. PMID 16536349</ref>
Some forms of OCD may be genetically linked to Tourette's.<ref>Pauls DL, Towbin KE, Leckman JF, et al. Gilles de la Tourette's syndrome and obsessive-compulsive disorder. Evidence supporting a genetic relationship. ''Arch Gen Psychiatry''. 1986 Dec;43(12):1180-2. PMID 3465280</ref> At least some forms of OCD are [[etiologic|etiologically]] related to Tourette syndrome and may be a different expression of the same factors that are important for the expression of tics."<ref>Miguel EC, do Rosario-Campos MC, Shavitt RG, et al. The tic-related obsessive-compulsive disorder phenotype and treatment implications. ''Adv Neurol.'' 2001;85:43-55. PMID 11530446</ref> However, the genetic relationship of ADHD to Tourette syndrome has not been fully established.<ref name=Denckla>Denckla MB. Attention deficit hyperactivity disorder: the childhood co-morbidity that most influences the disability burden in Tourette syndrome. ''Adv Neurol.'' 2006;99:17-21. PMID 16536349</ref>


==Diagnosis==
==Diagnosis==
According to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, [[DSM-IV-TR]], Tourette’s Disorder may be diagnosed when a person exhibits both multiple motor and one or more vocal tics (although these do not need to be concurrent) over the period of 1 year, with no more than 3 consecutive tic-free months. Previous editions of the DSM included a requirement for distress or impairment in social, occupational, or other important areas of functioning, but this requirement was removed in the most recent update of the manual, in recognition that not everyone with the diagnosis has distress or impairment to functioning. The onset must have been before the age of 18, and cannot be attributed to drug toxicity or another medical condition.<ref name=Behavenet> Behavenet. [http://web.archive.org/web/20050310121149/http://www.behavenet.com/capsules/disorders/touretteTR.htm Tourette's disorder]. Accessed 10 Mar 2005.</ref> Hence, other medical conditions which include tics or tic-like movements (such as [[autism]]) must be ruled out before conferring a Tourette's diagnosis.
According to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, [[DSM-IV-TR]], Tourette’s Disorder may be diagnosed when a person exhibits both multiple motor and one or more vocal tics (although these do not need to be concurrent) over the period of 1 year, with no more than 3 consecutive tic-free months. Previous editions of the DSM included a requirement for distress or impairment in social, occupational, or other important areas of functioning, but this requirement was removed in the most recent update of the manual, in recognition that not everyone with the diagnosis has distress or impairment to functioning. The onset must have been before the age of 18, and cannot be attributed the "direct physiological effects of a substance or a general medical condition".<ref name=Behavenet> Behavenet. [http://web.archive.org/web/20050310121149/http://www.behavenet.com/capsules/disorders/touretteTR.htm Tourette's disorder]. Accessed 10 Mar 2005.</ref> Hence, other medical conditions which include tics or tic-like movements (such as [[autism]] or other causes of [[tourettism]]) must be ruled out before conferring a Tourette's diagnosis.


There are no specific medical or screening tests which can be used in diagnosing Tourette's disorder.<ref name=phenomenology/> The diagnosis is made based on observation of the individual's symptoms and family history, and after ruling out secondary causes of tic disorders.<ref name=TSAFAQ/> In patients with a typical onset and a family history of tics or obsessive-compulsive disorder, a basic physical and neurological exam may be sufficient.<ref name=Bagheri/> If a physician believes that there may be another condition present which could explain tics, some tests may be ordered as necessary to rule out those other conditions. An example of this would be when diagnostic confusion between tics and [[seizure]] activity exists, which would call for an [[Electroencephalography|EEG]], or if there are indications that an [[MRI]] is warranted to rule out brain abnormalities. [[TSH]] levels can be measured to rule out [[hypothyroidism]], which can be a cause of tics. [[Brain imaging]] studies are not usually warranted. In teenagers or adults presenting with a sudden onset of tics and other behavioral symptoms, a [[Drug test#Urine drug screen|urine drug screen]] for [[cocaine]] and [[stimulants]] might be warranted. If a family history of [[liver disease]] is present, serum copper and [[ceruloplasmin]] levels can rule out [[Wilson's disease]].<ref name=Bagheri/> However, most cases are diagnosed by merely observing a history of tics, and medical tests are not always called for.<ref name=Zinner/><ref name=TSAFAQ/>
There are no specific medical or screening tests which can be used in diagnosing Tourette's disorder.<ref name=phenomenology/> The diagnosis is made based on observation of the individual's symptoms and family history, and after ruling out secondary causes of tic disorders.<ref name=TSAFAQ/> In patients with a typical onset and a family history of tics or obsessive-compulsive disorder, a basic physical and neurological exam may be sufficient.<ref name=Bagheri/> If a physician believes that there may be another condition present which could explain tics, some tests may be ordered as necessary to rule out those other conditions. An example of this would be when diagnostic confusion between tics and [[seizure]] activity exists, which would call for an [[Electroencephalography|EEG]], or if there are indications that an [[MRI]] is warranted to rule out brain abnormalities. [[TSH]] levels can be measured to rule out [[hypothyroidism]], which can be a cause of tics. [[Brain imaging]] studies are not usually warranted. In teenagers or adults presenting with a sudden onset of tics and other behavioral symptoms, a [[Drug test#Urine drug screen|urine drug screen]] for [[cocaine]] and [[stimulants]] might be warranted. If a family history of [[liver disease]] is present, serum copper and [[ceruloplasmin]] levels can rule out [[Wilson's disease]].<ref name=Bagheri/> However, most cases are diagnosed by merely observing a history of tics, and medical tests are not always called for.<ref name=Zinner/><ref name=TSAFAQ/>
Line 137: Line 137:
Dropping the criteria for impairment from the diagnosis resulted in higher prevalence estimates for TS (the question of "who has it?"). With TS prevalence estimates at 1% to 2%, the condition is cast in an entirely new light.
Dropping the criteria for impairment from the diagnosis resulted in higher prevalence estimates for TS (the question of "who has it?"). With TS prevalence estimates at 1% to 2%, the condition is cast in an entirely new light.


Discovering "what causes TS" may resolve the questions of what it is and who has it. Research has been affected by the problem of referred samples, which may not reflect broader populations of persons with Tourette's. The P.A.N.D.A.S. hypothesis remains contentious.
Discovering "what causes TS" may resolve the questions of what it is and who has it. The autosomal dominant inheritance model has not been validated. Research has been affected by the problem of referred samples, which may not reflect broader populations of persons with Tourette's.
The P.A.N.D.A.S. hypothesis remains contentious.


Expanding criteria for the diagnosis, and increasing awareness of the impact of co-occurring diagnoses result in further questions of how to study Tourette's. Developing and applying standardized instruments, along with awareness of ascertainment bias in recruitment sources, will be important in genetic studies. We don't know if "we lose both signals and are just adding noise to the experimental outcome"<ref name=Swerdlow/> when co-occurring conditions, such as OCD or ADHD, are included or excluded from study samples, or samples include/exclude children or adults, or patients with severe symptoms.
Expanding criteria for the diagnosis, and increasing awareness of the impact of co-occurring diagnoses result in further questions of how to study Tourette's. Developing and applying standardized instruments, along with awareness of ascertainment bias in recruitment sources, will be important in genetic studies. We don't know if "we lose both signals and are just adding noise to the experimental outcome"<ref name=Swerdlow/> when co-occurring conditions, such as OCD or ADHD, are included or excluded from study samples, or samples include/exclude children or adults, or patients with severe symptoms.

Revision as of 04:24, 2 September 2006

For the Nirvana song, see tourette's (song). For the band, see Tourettes (band).
Tourette syndrome
SpecialtyNeurology Edit this on Wikidata

Tourette syndrome (also called Tourette's syndrome, Tourette's disorder, Gilles de la Tourette syndrome, GTS or the more common Tourette's or TS) is an inherited neurological disorder with onset in childhood, characterized by the presence of multiple physical (motor) tics and at least one vocal (phonic) tic, which usually wax and wane. Tourette syndrome is defined as part of a spectrum of tic disorders, which includes transient tics and chronic tics.

Tourette syndrome was once considered a rare and bizarre syndrome, most often associated with the exclamation of obscene words or socially inappropriate and derogatory remarks (coprolalia). However, this symptom is present in fewer than 15% of persons with Tourette's. Furthermore, it is no longer considered a rare condition, but it may not always be identified because of the wide range of severity, with most cases classified as mild. The precise cause of Tourette syndrome is not known, but genetic and environmental factors each play a role.

People with Tourette's have normal life expectancy and intelligence. Notable individuals with Tourette syndrome are found across many professions and in all walks of life. The severity of the tics decreases for most children as they pass through adolescence, and extreme Tourette's in adulthood is a rarity. Medication is not needed for most cases. Although no medication is effective for all persons with tics, there are medications and therapies that can help when their use is warranted. Understanding, knowledge about the condition, and a supportive family and community are the best treatments.

The eponym was bestowed by Jean-Martin Charcot (1825 – 1893) after and on behalf of his resident, Georges Albert Édouard Brutus Gilles de la Tourette, (1859 – 1904), a French physician and neurologist, who published an account of nine patients with Tourette's in 1885.

Tourette syndrome is a common childhood-onset condition, with tics typically appearing around the ages of 5 to 7 and diminishing for most by adulthood.

Classification

Tics are sudden, repetitive, stereotyped, nonrhythmic, involuntary movements (motor tics) and utterances (phonic tics) that involve discrete muscle groups.[1] Tourette syndrome is one of several tic disorders, which are classified by the Diagnostic and Statistical Manual of Mental Disorders (DSM) according to type (motor or phonic tics) and duration (transient or chronic). Transient tic disorder consists of multiple motor tics, phonic tics or both, with duration of at least 4 weeks, but less than 12 months. Chronic tic disorder is either single or multiple, motor or phonic tics – but not both – which are present for more than a year.[2] Tourette's disorder is diagnosed when multiple motor tics, and at least one phonic tic, are present for more than a year. Although Tourette's is the more severe expression of the spectrum of tic disorders,[3] most cases are nonetheless mild.[4] There is a wide range of severity of symptoms in persons with Tourette syndrome, and mild cases may be undetected.[2]

Characteristics

Tics are movements or sounds "that occur intermittently and unpredictably out of a background of normal motor activity".[5] The tics of Tourette syndrome constantly change in number, frequency, severity, and anatomical location. Waxing and waning — a natural increase and decrease in severity and frequency of tics — occurs differently in each individual. Tics also occur in "bouts of bouts", which vary for each person.[1]

Coprolalia (the spontaneous utterance of socially objectionable or taboo words or phrases) is the most publicized symptom of Tourette syndrome, but it is not required for a diagnosis of Tourette's. Fewer than 15% of Tourette syndrome patients exhibit coprolalia.[6] Echolalia and palilalia occur in a minority of cases,[1] while more common tics are eye blinking, throat clearing, coughing, neck stretching, and shoulder shrugging.

File:Tim howard.jpg
Tim Howard, a football (soccer) goalkeeper from the United States with Tourette syndrome.

In contrast to the stereotyped movements of other movement disorders (e.g.; choreas, dystonias, myoclonus, and dyskinesias), the tics of Tourette's are temporarily suppressible and preceded by a premonitory urge.[7] Immediately preceding tic onset, most individuals with Tourette syndrome are aware of an urge,[8] which is similar to the need to sneeze or scratch an itch. Individuals describe the need to tic as the buildup of tension in a particular anatomical location,[9] which they consciously choose to release, as if the subject "had to do it".[10] Examples of the premonitory urge are the feeling of having something in one's throat, or a localized discomfort in the shoulders, leading to the need to clear one's throat or shrug the shoulders. The actual tic may be felt as relieving this tension or sensation, similar to scratching an itch. Another example is blinking to relieve an uncomfortable sensation in the eye. These urges and sensations, preceding the expression of the movement or vocalization as a tic, are referred to as "premonitory sensory phenomena". Published descriptions of the tics of Tourette's identify sensory phenomena as the core symptom of Tourette syndrome, even though they are not included in the diagnostic criteria.[11][12]

Tics are described as semi-voluntary or "unvoluntary",[5] because they are not strictly involuntary: they may be experienced as a voluntary response to an unwanted, premonitory urge. Tics are experienced as irresistible and must eventually be expressed.[5] People with Tourette syndrome are sometimes able to suppress their tics to some extent for limited periods of time, but doing so often results in an explosion of tics afterward.[2] People with Tourette syndrome may seek a secluded spot to release their symptoms after suppressing them in school or at work. Some people with Tourette syndrome may not be aware of the premonitory urge. Children may be less aware of the premonitory urge associated with tics than are adults, but their awareness tends to increase with maturity.[5] They may have tics for several years before becoming aware of premonitory urges. Children may suppress tics while in the doctor's office, so they may need to be observed while they are not aware they are being watched.[2] The ability to suppress tics varies among individuals, and may be more developed in adults than children.

Although there is no such thing as a "typical" case of Tourette syndrome,[2] the condition follows a fairly reliable course in terms of age of onset and the natural time course of severity of symptoms. Tics may appear up to the age of 18, but the most typical age of onset is five to seven.[1] The ages of statistical highest tic severity are 8 to 12 (average 10), with tics steadily declining for most patients as they pass through adolescence.[13] The most common, first-presenting tics are eye blinking, facial movements, sniffing and throat clearing. Initial tics are most frequent in midline body regions where there are many muscles, usually the head, neck and facial region.[2] This can be contrasted with the stereotyped movements of other disorders (such as stims and stereotypies of the autism spectrum disorders) which typically have an earlier age of onset, are more symmetrical, rhythmical, bilateral, and involve extremities (e.g.; flapping hands).[14] Tics appearing early in the course of the condition are frequently confused with other conditions such as allergies, asthma, and vision problems: pediatricians, allergists, and ophthalmologists are typically first to see a child with tics.[1]

Among patients whose symptoms are severe enough to warrant referral to clinics, obsessive-compulsive disorder (OCD) and attention-deficit hyperactivity disorder (ADHD) are often associated with Tourette's. Not all persons with Tourette syndrome will have ADHD or OCD, although in clinical populations, a high percentage of patients presenting for care do have ADHD.[3] Approximately 40% of patients with Tourette syndrome have "TS-only" or "pure TS", referring to Tourette syndrome in the absence of ADHD, OCD or other disorders.[15]

Causes

Further information: Causes and origins of Tourette syndrome

The exact cause of TS is not known, but both genetic and environmental factors are involved.[16] Genetic studies have proven that the overwhelming majority of cases of Tourette syndrome are inherited, although the exact mode of inheritance is not yet known.[17] In some cases, tics may not be inherited; these cases are identified as "sporadic" Tourette syndrome (also known as tourettism) because a genetic link is missing.[18]

Brain structures implicated in Tourette syndrome

A person with Tourette syndrome has about a 50% chance of passing the gene(s) to one of his/her children. Not everyone who inherits the genetic vulnerability will show symptoms: even close family members may show different levels of symptom severity. The gene(s) may express as Tourette syndrome, as a milder tic disorder (transient or chronic tics), or as obsessive compulsive symptoms with no tics at all. Only a minority of the children who inherit the gene(s) will have symptoms severe enough to require medical attention.[6] Gender appears to have a role in the expression of the genetic vulnerability, with males more likely to express tics than females.[2]

Studies suggest that non-genetic, environmental, infectious, or psychosocial factors — while not causing Tourette's — can influence the severity of the disorder.[2] Autoimmune processes may affect tic onset and exacerbation in some cases: the unproven and contentious hypothesis that Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections, P.A.N.D.A.S., plays a role in the onset of tic disorders and OCD is a current focus of research.[19][20]

The exact mechanism affecting the inherited vulnerability to Tourette syndrome has not been established, and the precise etiology is not known. Tics are believed to result from dysfunction in cortical and subcortical regions, the thalamus, basal ganglia, and frontal cortex.[16] Neuroanatomic models implicate failures in circuits connecting the brain's cortex and subcortex,[2] and imaging techniques implicate the basal ganglia and frontal cortex.[21][22] [23]

Some forms of OCD may be genetically linked to Tourette's.[24] At least some forms of OCD are etiologically related to Tourette syndrome and may be a different expression of the same factors that are important for the expression of tics."[25] However, the genetic relationship of ADHD to Tourette syndrome has not been fully established.[15]

Diagnosis

According to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, DSM-IV-TR, Tourette’s Disorder may be diagnosed when a person exhibits both multiple motor and one or more vocal tics (although these do not need to be concurrent) over the period of 1 year, with no more than 3 consecutive tic-free months. Previous editions of the DSM included a requirement for distress or impairment in social, occupational, or other important areas of functioning, but this requirement was removed in the most recent update of the manual, in recognition that not everyone with the diagnosis has distress or impairment to functioning. The onset must have been before the age of 18, and cannot be attributed the "direct physiological effects of a substance or a general medical condition".[26] Hence, other medical conditions which include tics or tic-like movements (such as autism or other causes of tourettism) must be ruled out before conferring a Tourette's diagnosis.

There are no specific medical or screening tests which can be used in diagnosing Tourette's disorder.[1] The diagnosis is made based on observation of the individual's symptoms and family history, and after ruling out secondary causes of tic disorders.[6] In patients with a typical onset and a family history of tics or obsessive-compulsive disorder, a basic physical and neurological exam may be sufficient.[3] If a physician believes that there may be another condition present which could explain tics, some tests may be ordered as necessary to rule out those other conditions. An example of this would be when diagnostic confusion between tics and seizure activity exists, which would call for an EEG, or if there are indications that an MRI is warranted to rule out brain abnormalities. TSH levels can be measured to rule out hypothyroidism, which can be a cause of tics. Brain imaging studies are not usually warranted. In teenagers or adults presenting with a sudden onset of tics and other behavioral symptoms, a urine drug screen for cocaine and stimulants might be warranted. If a family history of liver disease is present, serum copper and ceruloplasmin levels can rule out Wilson's disease.[3] However, most cases are diagnosed by merely observing a history of tics, and medical tests are not always called for.[2][6]

Other conditions which may manifest tics or stereotyped movements include developmental disorders, autism spectrum disorders,[27] and stereotypic movement disorder;[28] [29] other genetic conditions such as Huntington's disease, Neuroacanthocytosis, Hallervorden-Spatz syndrome, Idiopathic dystonia, Duchenne muscular dystrophy, Wilson's disease, Syndenham's chorea or Tuberous sclerosis. Other possibilities include chromosomal disorders such as Down syndrome, Klinefelter's syndrome, XYY syndrome, or Fragile X syndrome. Secondary or acquired causes of tics include drug-induced tics, head trauma, encephalitis, stroke, and carbon monoxide poisoning. Secondary causes of tics (not related to inherited Tourette syndrome) are commonly referred to as tourettism.[3][18] Dystonias, choreas, other genetic conditions, and secondary causes of tics should be ruled out in the differential diagnosis for Tourette syndrome.[3] The symptoms of Lesch-Nyhan syndrome may also be confused with Tourette syndrome.[14] Most of these conditions are rarer than tic disorders, and a thorough history and examination may be enough to rule them out, without medical or screening tests.[2]

Screening

Tourette syndrome patients may exhibit symptoms of other conditions along with their motor and phonic tics. Associated conditions include attention-deficit hyperactivity disorder (ADD or ADHD), obsessive-compulsive disorder (OCD), learning disabilities and sleep disorders.[30] Disruptive behaviors, overall functioning, and cognitive function in patients with co-occurring Tourette syndrome and ADHD may be accounted for by the comorbid ADHD, highlighting the importance of identifying and treating co-occurring conditions when they are present.[31][32][33][34]

Because co-occurring conditions like OCD or attention-deficit hyperactivity disorder can be more impairing than tics, these conditions should be included in an evaluation of patients presenting with tics.[2][3] "It is critical to note that the comorbid conditions may determine functional status more strongly than the tic disorder." [2]

Management

Further information: Treatment of Tourette syndrome

Treatment of Tourette syndrome focuses on identifying and helping the individual manage the most troubling symptoms. Most cases of Tourette's are mild and pharmacological treatment is not warranted: the prognosis is good for uncomplicated cases. In cases where treatment is warranted, treatment of Tourette syndrome can be divided into treatment of tics, and treatment of co-occurring conditions, which, when present, are often a larger source of impairment than the tics themselves. Not all persons with tics will also have co-occurring conditions, but when comorbid disorders are present, they often take treatment priority.

There is no cure for Tourette syndrome and no medication which works universally for all individuals without significant adverse effects. Knowledge and understanding are the best treatments available for tics. Management of the symptoms of Tourette's may include pharmacologic, behavioral and psychological therapies. While pharmacological intervention is reserved for more severe symptoms, treatment with other modalities may help avoid or ameliorate depression or social isolation, and improve supportive family functioning. Educating the patient, family, and surrounding community (school, church, friends, etc.) is a key part of treatment.

The majority of people with Tourette syndrome require no medication, but medication is available to help when symptoms interfere with functioning.[6] Because children with tics often present to physicians when their tics are at their highest severity, and because of the waxing and waning nature of tics, it is recommended that medication not be started immediately or changed often. Frequently, the tics subside with understanding of the condition and a supportive environment. When medication is used, the goal is not to eliminate symptoms: it should be used at the lowest possible dose that manages symptoms without adverse effects.

The classes of medications with the most proven efficacy in treating tics — typical and atypical neuroleptics — can have long-term and short-term adverse effects.[3] The antihypertensive agents, clonidine (Catapres®) and guanfacine (Tenex®), are also used to treat tics. Stimulants and other medications may be useful in treating ADHD when it co-occurs with tic disorders. Drugs from several other classes of medications can be used as alternatives when stimulant trials fail. Clomipramine (Anafranil®), a tricyclic antidepressant, and SSRIs, a class of antidepressants including fluoxetine, sertraline, and fluvoxamine, may be prescribed when a Tourette syndrome patient also has symptoms of obsessive-compulsive disorder.

Cognitive Behavioral Therapy (CBT) is a useful treatment when OCD is present, and there is increasing evidence supporting the use of habit reversal in the treatment of tics. Relaxation techniques, such as exercise, yoga or meditation, may also be useful in relieving stress that may aggravate tics.

Prognosis

File:Malraux.jpg
André Malraux, French author, adventurer, and statesman with Tourette syndrome

Tourette syndrome is a spectrum disorder, meaning the severity of the condition ranges from mild to severe. However, it should be emphasized that "the majority of cases can be categorized as mild" and require no treatment.[4] Those with mild cases may be minimally impacted by symptoms, to the extent that casual observers might not know of their condition. The overall prognosis is positive, but a minority of children with Tourette syndrome have severe symptoms that persist into adulthood.[16] A study of 46 subjects at 19 years of age found that 80% had minimum to mild impact on overall functioning, while 20% had at least a moderate impact on their overall functioning.[1] The rare minority of severe cases can inhibit or prevent the individual from engaging in common activities such as holding a job or having a fulfilling social life. In a follow-up study of 31 adults with Tourette's, all patients completed high school, 52% finished at least 2 years of college, and 71% were employed or pursuing higher education full time.[35]

Regardless of symptom severity, individuals with Tourette syndrome can expect to live a normal life span. Although Tourette syndrome symptoms may be lifelong and chronic for some, it is not a degenerative condition and is not life-threatening. Life span and intelligence are normal, although learning disabilities may be present.[6] There is currently no reliable means of predicting the outcome for any individual. The gene or genes for Tourette syndrome have not been identified, and there is no potential "cure".[6]

Multiple studies have demonstrated that the condition in most children improves with maturity. Tics may be at their highest severity at the time that they are brought to diagnostic awareness, and often improve with understanding of the condition. The statistical age of highest tic severity is typically between 8 and 12, with most individuals experiencing steadily declining tic severity as they pass through adolescence. One study showed no correlation with tic severity and the onset of puberty, in contrast to the popular belief that tics increase at puberty. In many cases, complete remission of tic symptoms occurs after adolescence.[13][36] However, a study using videotape to record tics in adults found that, although tics diminished in comparison to childhood and all measures of tic severity improved by adulthood, 90% of adults still had tics. Half of the adults who considered themselves tic-free still had evidence of tics.[35]

It is not uncommon for parents of affected children to be unaware that they, too, may have had tics as children. Because Tourette syndrome tends to remit or subside in severity as one matures, and because milder cases of Tourette's are now more likely to be recognized, the first realization that a parent had tics as a child may not come until their offspring are diagnosed. It is not uncommon for several members of a family to be diagnosed together, as parents bringing children to a physician for an evaluation of tics come to the realization that, "I did that, too, as a child."

Children with Tourette's may suffer socially if their tics are viewed as "bizarre". If a child has disabling tics, or tics which interfere with social or academic functioning, supportive psychotherapy or school accommodations can be helpful.[6] Because comorbid conditions (such as ADHD or OCD) can cause more impact on overall functioning than tics, a thorough evaluation for comorbidity is called for when symptoms and impairment warrant.[3]

A supportive environment and family generally gives one skills to manage the disorder. Persons with Tourette syndrome may learn to camouflage socially inappropriate tics or channel the energy of their tics into some other endeavor, to their advantage. Accomplished musicians, athletes, public speakers, and professionals from all walks of life are found among people with Tourette syndrome. Outcome in adulthood is associated more with the significance of having severe tics as a child, than with the actual severity of the tics. A person who was misunderstood, punished, or teased at home or at school will fare worse than children who enjoyed an understanding and supportive environment.[1]

An age-matched controlled study on a small (13) group of individuals with Tourette syndrome found that cognitive control is enhanced in young people with Tourette syndrome, possibly because the need to suppress tics results in more efficient control of inhibitions, a skill that confers an advantage when switching between tasks.[37]

Epidemiology

Tourette syndrome has historically been described as a rare disorder, with about 5 to 10 people in 10,000 having the condition.[2] However, multiple studies published since 2000 demonstrate that the prevalence is much higher than previously thought, and that Tourette syndrome can no longer be considered rare. Contemporary prevalence estimates range from 1 to 3 per 1,000[38] to 10 per 1,000.[39] A large, community-based study suggested that over 19% of school-age children have tics, with almost 4% of children in regular education fulfilling the diagnostic criteria for Tourette Syndrome. The children with tic disorders in that study were usually undiagnosed.[40] As many as 1 in 100 people may experience some form of tic disorder, which includes transient tics, chronic tics, or Tourette Syndrome.[30] Tourette syndrome is found among all social, racial and ethnic groups,[30][41] and males are affected 3 to 4 times more often than females.[2]

Tourette syndrome is frequently misdiagnosed or underdiagnosed, partly because of the wide expression of severity, ranging from mild (the majority of cases) or moderate, to severe (the rare, but more widely-recognized and publicized cases). Because the tics of Tourette syndrome tend to remit or subside with maturity, such that a diagnosis may no longer be warranted for many adults, prevalence rates in pediatric populations are higher than those in adult populations.[13]

Mild cases of Tourette syndrome are less likely to come to tertiary or clinical attention, raising the possibility of ascertainment bias in referred populations. There are few broad-based population studies, and most older epidemiological studies of Tourette's were based on individuals referred to specialty clinics.[42][43] Children with milder symptoms are not likely to be referred to specialty clinics, so most studies of Tourette's patients have an inherent bias towards more severe cases.[43][44] Epidemiologic methods are vulnerable to errors, because of the variance in symptom severity and because symptoms are not always recognized by the patient or family.[45]

History

Jean-Martin Charcot (1825 - 1893) was a French neurologist and professor who bestowed the eponym for Tourette syndrome on behalf of his resident, Georges Albert Édouard Brutus Gilles de la Tourette. Charcot is shown here during a lesson with a "hysterical" woman patient at the Salpêtrière hospital.

A thorough history of Tourette syndrome is published in Kushner's A Cursing Brain? : The Histories of Tourette Syndrome. A French doctor, Jean Marc Gaspard Itard, reported the first case of Tourette syndrome in 1825,[46] describing Marquise de Dampierre, an important woman of nobility in her time.[4] Jean-Martin Charcot, an influential French physician, assigned his resident Georges Albert Édouard Brutus Gilles de la Tourette, a French physician and neurologist, to study patients at the Salpêtrière Hospital, with the goal of defining an illness distinct from hysteria and from chorea. Charcot and Tourette believed that the "tic illness" they had observed was an untreatable, chronic, and progressive hereditary condition. In 1885, Gilles de la Tourette published an account of nine patients, Study of a Nervous Affliction, concluding that a new clinical category should be defined.[47] His description included accounts of Marquise de Dampierre previously described by Itard, as a reclusive aristocratic lady who "ticked and blasphemed" from the age of 7 until her death at the age of 80 years. Gilles de la Tourette describe the common feature of involuntary movements or tics in all 9 patients. The eponym was later bestowed by Charcot after and on behalf of Gilles de la Tourette.[48][49]

Little progress was made over the next century in explaining or treating tics. With limited clinical experience, involving typically 1 or 2 patients, authors advanced different ideas, including brain lesions similar to those resulting from rheumatic chorea or encephalitis lethargica as a cause of tics, faulty mechanisms of normal habit formation, and treatment with Freudian psychoanalysis. The psychogenic view prevailed well into the 20th century.[49]

The possibility that movement disorders, including Tourette syndrome, might have an organic origin was raised when an encephalitis epidemic from 1918-1926 led to a subsequent epidemic of tic disorders. But, psychoanalytic theory was so dominant, that it was claimed that an organic component alone would not be sufficient to produce Tourette Syndrome. At the time, psychiatrists believed patients with tics must also be suffering from unresolved psychological disturbances or psychosexual conflicts, and psychiatric intervention was the preferred method of treatment. Patients and their families were told that their own psychological maladjustments were to blame for their symptoms, adding to the burden carried by the patients and their families. Until the early 1970s, psychoanalysis was the preferred intervention for Tourette syndrome.[50]

During the 1960s and 1970s, as the beneficial effects of haloperidol (Haldol) on tics became known, the psychoanalytic approach to Tourette syndrome was questioned. The turning point came in 1965, when Dr. Arthur K. Shapiro treated a Tourette’s patient with Haldol. Dr. Shapiro and his wife, Elaine Shapiro (Ph.D.), reported the treatment in a 1968 article, severely criticizing the psychoanalytic approach to treating the condition.[50]

The Shapiros, working with the patient families who founded the Tourette Syndrome Association (TSA) in 1972, advanced the argument that Tourette's was neurological rather than psychological.[50] Since the 1990s, a more neutral view of Tourette's is emerging[49] as a condition involving an interaction between biological vulnerability and adverse environmental events.[2]

Social impact and notable cases

Main article: Sociological and cultural aspects of Tourette syndrome
Samuel Johnson (1709 – 1784) circa 1772, painted by Sir Joshua Reynolds.

Discussions with adults who have Tourette syndrome reveal that not everyone wants treatment or a "cure", especially if that means they may "lose" something else in the process.[51][52] Some believe that there may even be latent advantages associated with the genetic vulnerability.[53] Notable individuals with Tourette syndrome can be found in all walks of life, including musicians, athletes, and authors.

The best known example of a person who may have used obsessive-compulsive traits to advantage is Dr Samuel Johnson, lexicographer, who certainly had Tourette syndrome as evidenced by the writings of James Boswell.[54] Johnson wrote A Dictionary of the English Language in 1747, and was a prolific writer, poet, and critic.

Some authors have speculated that Mozart may have had Tourette syndrome.[55][56] However no Tourette syndrome expert or organization has presented credible evidence to show that Mozart had Tourette's.[57]

The entertainment industry often depicts those with Tourette syndrome as being social misfits whose only tic is coprolalia, which has furthered stigmatization and the general public's misunderstanding of persons with Tourette's. The symptoms of Tourette syndrome – namely, coprolalia – are also fodder for radio and television talk shows.

Research directions and controversies

The direction of current and future research in Tourette syndrome was delineated in a 2005 journal article[19] by the outgoing chairman of the TSA Scientific Advisory Board. Swerdlow divides the research landscape into five broad questions about Tourette's: "what is it, who has it, what causes it, how do we study it, and how do we treat it"?

According to Swerdlow,[19] "we still lack consensus on the definition of TS." He calls this "the 'core' TS conundrum". Since vocal tics result from a "motor event (ie, a contracting diaphragm moving air through the upper airways)", TS could be defined as a disorder of motor tics, eliminating the distinction between TS and the other tic disorders. Because "individuals with tics alone may not be functionally impaired", should TS, as currently defined, be a DSM diagnosis? Swerdlow highlights the importance of studies in new areas, such as behavioral techniques, and that "the whole-cloth dismissal of psychologic forces in the pathobiology of TS was a strategic error". Questions remain about whether co-occurring conditions should be part of the core definition, and why sensory phenomena, which are a core part of Tourette's, are not part of the diagnostic criteria.

Dropping the criteria for impairment from the diagnosis resulted in higher prevalence estimates for TS (the question of "who has it?"). With TS prevalence estimates at 1% to 2%, the condition is cast in an entirely new light.

Discovering "what causes TS" may resolve the questions of what it is and who has it. The autosomal dominant inheritance model has not been validated. Research has been affected by the problem of referred samples, which may not reflect broader populations of persons with Tourette's. The P.A.N.D.A.S. hypothesis remains contentious.

Expanding criteria for the diagnosis, and increasing awareness of the impact of co-occurring diagnoses result in further questions of how to study Tourette's. Developing and applying standardized instruments, along with awareness of ascertainment bias in recruitment sources, will be important in genetic studies. We don't know if "we lose both signals and are just adding noise to the experimental outcome"[19] when co-occurring conditions, such as OCD or ADHD, are included or excluded from study samples, or samples include/exclude children or adults, or patients with severe symptoms.

Tourette's is a heterogeous condition, with waxing and waning symptoms. The inherent changing nature of its core symptoms complicates research design. Results from case studies may not be borne out by controlled studies, stimulants may be under utilized, and behavioral therapies are understudied. High profile media coverage focuses on treatments that do not have established safety or efficacy e.g.; deep brain stimulation.

See also

References

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  57. ^ Tourette Syndrome Association: Did Mozart really have TS? Accessed online 14 Aug 2002.

Further reading

External links

Video clips of tics

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