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Essentials of Diagnosis
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DSM-IV-TR Diagnostic Criteria
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Both multiple motor and one or more vocal tics have been present at some time during the illness, although not necessarily concurrently. (A tic is a sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalization.)
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.
The onset is before age 18 years.
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 postviral encephalitis).
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Chronic Motor or Vocal Tic Disorder
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Single or multiple motor or vocal tics (i.e., sudden, rapid, recurrent, nonrhythmic, stereotyped motor movements or vocalizations), but not both, have been present at some time during the illness.
The tics occur many times a day 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.
The onset is before age 18 years.
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 postviral encephalitis).
Criteria have never been met for Tourettes Disorder.
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Single or multiple motor and/or vocal tics (i.e., sudden, rapid, recurrent, nonrhythmic, stereotyped motor movements or vocalizations)
The tics occur many times a day, nearly every day for at least 4 weeks, but for no longer than 12 consecutive months.
The onset is before age 18 years.
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 postviral encephalitis).
Criteria have never been met for Tourettes Disorder or Chronic Motor or Vocal Tic Disorder.
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Tic Disorder Not Otherwise Specified
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This category is for disorders characterized by tics that do not meet criteria for a specific Tic Disorder. Examples include tics lasting less than 4 weeks or tics with an onset after age 18 years.
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(Adapted with permission from Diagnostic and Statistical Manual of Mental Disorders, 4th edn. Text Revision. Copyright 2000 American Psychiatric Association.)
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General Considerations
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Transient tic behaviors are commonplace among school-age children. Estimates range between 4% and 24% of school-age children experiencing tics. The number of children experiencing chronic motor tic disorders is roughly one-quarter this number. Once thought to be much rarer, the current lifetime prevalence estimates for TS ranges from 0.1% to 1%.
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The prevalence of tic disorders peaks during the late first and early second decades of life due to the clinical course of the disorder. They are roughly one-third as prevalent in adulthood. Boys are about twice as likely to be affected by tic disorders as girls.
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The current understanding of Tourette syndrome (TS) provides a good working model for understanding the pathogenesis of other childhood neuropsychiatric disorders: a genetically determined vulnerability, age-dependent expression of symptoms reflecting maturational factors, sexual dimorphism, stress-dependent fluctuations in symptom severity, and environmental influences on the phenotypical expression of the tic.
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Strong evidence implicates the basal ganglia and corticostriatal−thalamocortical (CSTC) abnormalities as central to the pathogenesis of tics. Indirect evidence for the involvement of the basal ganglia in the pathogenesis of TS comes from the association with basal ganglia pathology of other movement disorders such as Sydenham's chorea, Huntington's disease, hemiballismus and Parkinson's disease. Direct evidence supporting CSTC abnormalities in TS comes from neuroimaging, neuropathological and neurosurgical studies.
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CSTC loops are multiple, parallel, but partially overlapping, neuroanatomical circuits, relaying information from most regions of the cortex to subcortical areas, particularly the striatum and thalamus, which in turn project to a subset of the original cortical areas. In CSTC loops, the basal ganglia can be viewed as a way station between intention and action (thought, affect and movement). Tics, repetitive and stereotyped movements are believed to arise from imbalances in focal populations in the basal ganglia circuits. A tic may arise through failure of inhibition of a discrete population of striatal projection neurons which become abnormally active and cause an unwanted disinhibition of a corresponding group of thalamocortical projection neurons. Thus a cortical motor pattern generator is activated so that unintended urges and motor and vocal tics are triggered.
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Altered dopaminergic functioning has also been strongly implicated in the pathogenesis of TS. Evidence for abnormal dopamine neurotransmission in TS is inferred from two clinical observations. First, blockade of dopamine receptors by neuroleptic drugs suppresses tics in a majority of patients. In addition, dopamine-releasing drugs such as cocaine and amphetamines have been reported to precipitate or exacerbate tics. It has been shown that TS patients release more dopamine at dopaminergic synapses in response to amphetamine. Second, the importance of dopamine in TS is supported by brain imaging using dopamine ligands in single photon emission computed tomography and positron emission tomography. In one twin study, tic severity was related to dopamine D2 receptor binding in the head of the caudate nucleus.
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Although the particular genetic factors responsible for TS remain largely undiscovered, there is a sizable heritable component responsible for this illness. Early twin studies have suggested that the concordance rate for TS among monozygotic twin pairs is greater than 50% while the concordance of dizygotic twin pairs is about 10%. If twins with chronic motor tic disorder are included, concordance figures increase to 77% for monozygotic and 30% for dizygotic twin pairs. Differences in the concordance of monozygotic and dizygotic twin pairs indicate that genetic factors play an important role in the etiology of TS and related conditions. These figures also suggest that nongenetic factors are critical in determining the nature and severity of the clinical syndrome.
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The overall risk that an offspring of a parent with TS will develop TS is approximately 10–15%, while the risk of offspring developing a tic disorder (20–29%) or obsessive–compulsive disorder (OCD) (12–32%) is slightly higher. The risk of developing tic disorders in male offspring is higher than for females, while the risk of developing OCD is lower.
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Recently, an analysis of a chromosomal anomaly in one TS patient led to the identification of two sequence variants in the SLITRK1 gene in approximately 1% of TS cases. Specifically, among 174 unrelated probands with TS, one frameshift mutation and two identical variants in the 3′ untranscribed region of this gene were identified. None of these anomalies was demonstrated in over 3,600 controls. SLITRK1 mRNA is expressed in the human fetal brain at 20 weeks gestation in multiple neuroanatomical areas implicated in TS neuropathology including the cortical plate, striatum, globus pallidus, thalamus and subthalamic nucleus. While other genes of major effect are likely to be found, it is becoming ever clear that TS is likely to be a polygenetic disorder with complex gene–environment interactions that have yet to be fully elucidated.
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Environmental Factors
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The existence of monozygotic twins discordant for tic severity emphasizes the importance of environmental factors in the phenotypic expression of TS. In monozygotic twins discordant for tic severity, the twin with more severe tics has usually had the lower birth weight and has a greater number of dopamine receptor sites in the caudate nucleus. In observational and case control studies, low (Activity, Pulse, Grimace, Appearance, and Respiration); APGAR scores, stressful maternal life circumstances during pregnancy and maternal first-trimester nausea are risk factors for TS.
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Tic disorders have long been identified as “stress-sensitive” conditions. Typically, symptom exacerbations follow in the wake of stressful life events. These events need not be adverse in character. Clinical experience suggests that in some unfortunate instances a vicious cycle can be initiated in which tic symptoms are misunderstood by the family and teachers, leading to active attempts to suppress the symptoms by punishment and humiliation. These efforts can lead to a further exacerbation of symptoms and an increase in stress in the child's interpersonal environment. Prospective longitudinal studies have begun to examine systematically the effect of intramorbid stress. These studies indicate that patients with TS experience more stress than matched healthy controls and that antecedent stress may play a role in subsequent tic exacerbations.
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Post-infectious autoimmune mechanisms have been implicated in a small number of post-streptococcal cases of TS and OCD known as Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal (PANDAS) infections. PANDAS cases are characterized by a sudden onset of symptoms, episodic course, and abrupt symptom exacerbations, sometimes accompanied by adventitious movements. The most salient differentiating factor between PANDAS and other cases of TS and OCD is an exacerbation of OCD and tic symptoms accompanied by positive streptococcal throat cultures, increased antistreptoccal and antineuronal antibodies, but no evidence of rheumatic fever. Evidence that PANDAS and post-streptococcal autoimmune factors are associated with some cases of tics and OCD comes from a variety of sources. Sydenham's chorea, a late autoimmune sequela of rheumatic fever, is often accompanied by tics, mood changes, OCD, attention-deficit hyperactivity disorder (ADHD) and anxiety. There is a large series of over 50 children in whom exacerbations of OCD or tics were accompanied by positive streptococcal throat cultures and increased antistreptoccal and antineuronal antibodies without evidence of rheumatic fever. One case-control study found an increased proportion of group A β-hemolytic streptococcal (GABHS) infections (odds ratio = 3.05) within the preceding 3 months in children newly-diagnosed with TS compared to well-matched controls. This suggests a role for post-streptococcal autoimmune factors in a large proportion of cases. A larger odds ratio (12.1) was demonstrated when subjects had multiple GABHS infections in the previous year, suggesting a dose-dependent effect of exposure to infection. However, prospective longitudinal studies have failed to provide evidence that newly acquired GABHS infections precede tic exacerbations. The relative prevalence of PANDAS cases and the importance of autoimmune mechanisms to TS are controversial.
Abelson JF,Kwan KY,O'Roak BJ, et al.: Sequence variants in SLITRK1 are associated with TS.
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Hyde TM,Aaronson BA,Randolph C, et al.: Relationship of birth weight to the phenotypic expression of gilles de la TS in monozygotic twins.
Neurology 1992;42:652–658.
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Kalanithi PS,Zheng W,Kataoka Y et al.: Altered parvalbumin-positive neuron distribution in basal ganglia of individuals with tourette syndrome.
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Khalifa N,von Knorring AL: Tourette syndrome and other tic disorders in a total population of children: Clinical assessment and background.
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Leckman JF,Vaccarino FM,Kalanithi PS,Rothenberger A: Tourette syndrome: A relentless drumbeat – driven by misguided brain oscillations.
J Child Psychol Psychiatry 2006;47(6):537–550.
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Luo F,Leckman JF,Katsovich L, et al.: Prospective longitudinal study of children with tic disorders and/or obsessive–compulsive disorder: Relationship of symptom exacerbations to newly acquired streptococcal infections. Pediatrics 2004;113:578–585.
Mell LK,Davis RL,Owens D: Association between streptococcal infection and obsessive–compulsive disorder, TS and Tic disorder.
Pediatrics 2005;116:56–60.
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McMahon WM,Carter AS,Fredine N,Pauls DL: Children at familial risk for tourette's disorder: Child and parent diagnoses.
Am J Med Genet 2003;121:105–111.
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Peterson BS,Thomas P,Kane MJ, et al.: Ganglia volumes in patients with gilles de la tourette syndrome.
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Scahill L,Sukhodolsky DG,Williams SK,Leckman JF: Public health significance of tic disorders in children and adolescents.
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Swedo SE,Leonard HL,Garvey M, et al.: Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections: Clinical description of the first 50 cases.
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Tics are sudden, repetitive movements, gestures, or utterances that typically mimic an aspect of normal behavior. Individual tics rarely last more than a second. Many tics occur in bouts with brief inter-tic intervals of less than one second. Individual tics can occur singly or together in an orchestrated pattern. They vary in intensity or forcefulness. Motor tics, which can be viewed as disinhibited fragments of normal movement, can vary from simple, abrupt movements such as eye blinking, nose twitching, head or arm jerking, or shoulder shrugging to more complex movements that appear to have a purpose, such as facial or hand gestures or sustained looks. These two phenotypic extremes of motor tics are classified as simple and complex motor tics respectively. Similarly, phonic tics can be classified into simple and complex. Simple vocal tics are sudden, meaningless sounds such as throat clearing, coughing, sniffing, spitting, or grunting. Complex phonic tics are more protracted, meaningful utterances, which vary from prolonged throat clearing to syllables, words or phrases and to even more complex behaviors such as repeating ones own words (palalalia) or those of others (echolalia) and, in rare cases, the use of obscenities (coprolalia).
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The severity of tics in TS waxes and wanes throughout the course of the disorder. The tics of TS and other tic disorders are highly variable from minute-to-minute, hour-to-hour, day-to-day, week-to-week, month-to-month, and even year-to-year. Tic episodes occur in bouts, which in turn also tend to cluster. Tic symptoms, however, can be exacerbated by stress, fatigue, extremes of temperature and external stimuli (e.g., in echolalia). Intentional movement attenuates tics in the affected area and intense involvement in activities tends to dissipate tic symptoms.
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Many individuals with tics, especially those post-pubertal, are aware of premonitory urges: feelings of tightness, tension, or itching that are accompanied by a mounting sense of discomfort or anxiety relieved only by the performance of a tic. Premonitory urges are similar to the sensation preceding a sneeze or an itch. Premonitory urges cause many TS patients to suffer from an endless cycle of rising tension and tic performance because the relief provided by tic performance is ephemeral. Thus, soon after tic performance the tension of the premonitory urge again rises to a crescendo. A majority of patients also report a fleeting sense of relief after a bout of tics has occurred. Most are able to suppress their tics for short intervals of time.
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With increasing awareness of premonitory urges, TS patients begin to exhibit a variable degree of voluntary control over tic performance. 92% of TS subjects in one study reported that the tics they exhibited were either partially or totally voluntary. However, this voluntary control should be likened to that governing eye blinking. Eye blinking and tics can both be inhibited voluntarily, but only for a limited period of time and only with mounting discomfort. Thus, some adult TS patients are able to demonstrate nearly complete control over when their tics will occur. However, when complete or near complete control of tics is present, resistance to the mounting tension of premonitory urges can produce mental and physical exhaustion even more distracting than the tics themselves.
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The tics, which are the most prominent feature of TS, may be neither the first nor the most impairing psychological disturbance TS patients endure. Children with TS have higher rates of OCD, ADHD, and disinhibited speech and behavior compared to the general population. In one study, 65% of TS patients in late adolescence regarded their behavioral problems (including ADHD and OCD) and learning difficulties to have had an equal or greater impact on their life function than the tics themselves did. In the natural course of comorbid psychiatric illness in TS, ADHD symptom, typically precede the onset of tic symptoms by a couple of years, whereas OCD symptoms typically present around the age of 12–13 after tics have reached their peak severity. Approximately 50% of children with TS experience comorbid ADHD, and an even greater proportion of children with comorbid disorders reach clinical attention. Roughly one-third to one-half of TS patients will experience clinically significant OCD symptoms during the course of their lifetime. Figure 44–1 depicts the clinical course of comorbid ADHD and OCD symptoms in children with tic disorders.
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Instruments for Diagnosis and Measurement
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Direct observational methods (e.g., videotaped tic–counting) are the most objective measures of tic severity. However, the frequency of tics varies dramatically according to setting and activity. In addition, many individuals with TS can suppress their symptoms for brief periods of time. Thus, clinical rating scales are the preferred method for assessing initial tic severity and measuring change in tic severity. The Yale Global Tic Severity Scale is a clinician-rated, semi-structured scale that begins with a systematic inventory of tic symptoms rated as present or absent over the past week. Current motor and phonic tics are then rated separately according to number, frequency, intensity, complexity, and interference, in accordance with 6-point ordinal scales (0 = absent; 1 through 5 for severity). Three scores are yielded: Total Motor, Total Phonic and Total Tic. Self-report inventories such as the Yale Child Study Center TS Obsessive–Compulsive Disorder Symptom Questionnaire can be completed by the family prior to their initial consultation. They are valuable ancillary tools in order to gain a long−term perspective of the child's developmental course and the natural history of the tic disorder. The Yale Global Tic Severity Scale and Yale Child Study Center TS Obsessive–Compulsive Disorder Symptom Questionnaire are freely available.
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Laboratory Findings and Imaging
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At present, no laboratory testing or neuroimaging is useful in diagnosing or treating tic disorders. However, strong evidence from neuroimaging, neuropathological and neurochemical studies implicates abnormalities in the basal ganglia and CSTC circuits in the pathogenesis of TS. On volumetric MRI, individuals with TS have smaller caudate volume than healthy controls. Reduced caudate volume in children with TS has been associated with increased tic and OCD severity in adulthood. Functional neuroimaging has revealed increased activation of the frontal cortex and caudate during willful tic suppression. This increased activation of frontal cortex and caudate is in turn correlated with decreased activity of the globus pallidus, putamen, and thalamus. Positron emission tomography studies in TS have demonstrated increased striatal dopamine receptor and transporter densities and increased amphetamine induced dopamine release in the putamen.
Bloch MH,Leckman JF,Zhu H, et al.: Caudate volumes in childhood predict symptom severity in adults with TS.
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Bloch MH,Peterson BS,Scahill L et al.: Adulthood outcome of tic and obsessive-compulsive symptom severity in children with TS.
Arch Pediatr Adolesc Med 2006;160:65–69.
[PubMed: 16389213]
Cheon KA,Ryu YH,Namkoong K, et al.:
Dopamine transporter density of the basal ganglia assessed with [123I] IPT SPECT in drug-naive children with tourette's disorder.
Psychiatry Res 2004;130:85–95.
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Leckman JF,Riddle MA,Hardin MT, et al.: The yale global tic severity scale: Initial testing of a clinician-rated scale of tic severity.
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Leckman JF,Walker DE,Cohen DJ: Premonitory urges in TS.
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Leckman JF,Zhang H,Vitale A, et al.: Course of tic severity in TS: The first two decades.
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Peterson BS,Skudlarski P,Anderson AW, et al.: A functional magnetic resonance imaging study of tic suppression in TS.
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Peterson BS,Thomas P,Kane MJ, et al.: Ganglia volumes in patients with gilles de la tourette syndrome.
Arch Gen Psychiatry 2003;60(4):415–424.
[PubMed: 12695320]
Singer HS,Szymanski S,Giuliano J, et al.: Elevated intrasynaptic
dopamine release in tourette's syndrome measured by PET.
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Sukhodolsky DG,Scahill L,Zhang H et al.: Disruptive behavior in children with tourette's syndrome: Association with ADHD comorbidity, tic severity, and functional impairment.
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Differential Diagnosis
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Tic disorders must be distinguished from movement disorders caused by general medical conditions (e.g., Huntington's disease, stroke, Lesch-Nyhan syndrome, Wilson's disease, Sydenham's chorea, multiple sclerosis, postviral encephalitis, head injury) or the direct effects of a drug (e.g. akathisia and tardive dyskinesia associated with neuroleptic medication). Table 44–1 defines the major types of movements that commonly need to be distinguished from tics. Medical and family history, movement morphology, rhythm, and modifying influences are usually sufficient for making the diagnosis. Onset of movements prior to age 18, a waxing-and-waning course of symptoms and the changing of the specific tic movements over time are characteristic of TS.
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In children, tics need to be distinguished from the stereotypies of stereotyped movement disorders or pervasive developmental disorder. Stereotypies typically have an earlier age of onset than tics, are bilateral rather than unilateral, and have a soothing quality. Table 44–2 contrasts tics and stereotypies. Complex tics need to be distinguished from the compulsions of OCD. Making this particularly difficult is the high comorbidity between the two conditions. Compulsions are usually performed in response to an obsession and preceded by anxiety, worry, or concern, whereas tics are generally performed in response to a physical sensation or urges. Compulsions typically are more elaborate than tics and are more likely to resemble “normal” behavior. Often a diagnosis of both OCD and tic disorder are warranted in the same individual.
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Given the usual waxing and waning course of tic disorders, it is probable that any intervention performed in response to symptom exacerbation will lead to clinical improvement. It is usually thus most prudent to treat overall, long-term symptom severity rather than chasing individual ebbs and flows in the natural course of the illness. Interventions should be started with the goal of reducing tics (and the side effects of treatment) to a level that minimizes social and educational impairment rather than to eliminate the tics completely (which will be unsuccessful in the majority of cases). Many cases of TS can be successfully managed without medication. When patients present with coexisting ADHD, OCD, depression, or bipolar illness it is usually better to treat these “comorbid” conditions first, as their successful treatment will often diminish tic severity.
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Usual clinical practice focuses initially on educational and supportive intervention. Pharmacological treatments are typically held in reserve. The decision to employ psychoactive medication is usually made if the educational and supportive interventions have been in place for a period of months and it is clear that the tic symptoms are persistently severe and a source of impairment in terms of self-esteem, relationships with family or peers, or the child's school performance.
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Psychoeducational Interventions
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Educating the patient, his family members, teachers, and peers is among the most important interventions available. It should be undertaken for nearly all patients with tic disorders. Family psychoeducation should focus on the following:
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Tics are not voluntary or provocative. They typically occur in “bouts” during which tics appear in rapid succession followed by tic-free intervals.
Physical sensations like an itch or before a sneeze are experienced by many patients prior to tics. TS is a sensorimotor disorder. A momentary sense of relief follows the tic.
Many patients are able to suppress tics over the short term but often at the expense of increasing discomfort and distraction due to the premonitory urges. It is not uncommon for a child to have relatively minor tics at school and then to let loose a bout of tics after coming home.
Tics increase and decrease in severity over time. Due to the natural ebb and flow of symptoms, any interventions started during an exacerbation of tic severity may appear successful, because of a natural decline in symptom severity.
Symptoms usually improve by adulthood. This information contradicts impressions gained from the lay literature that typically focuses on the most extreme cases.
Tics tend to be exacerbated by fatigue, sleeplessness, stress, excitement, changes in temperature, and streptococcal infection. Tics often tend to be alleviated when a child is deeply engaged in a motor activity such as sports, playing musical instruments, or dancing. The exact exacerbating and alleviating factors are highly individualized. Good sleep and regular exercise improve tics.
Comorbid ADHD, OCD, learning disabilities, and disruptive or disinhibited behaviors may occur. Improving these disorders often leads to an improvement in the tics.
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Resources to help educate parents about tic disorders are available at the Tourette Syndrome Association website: www.tsa-usa.org
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Perhaps equally important is educating the school. By educating the educators, clinicians can promote a positive and supportive environment in the classroom. If possible, teachers should respond to outbursts of tics with grace and understanding. Repeated scolding is counterproductive. The child may develop opposition to authority figures and be reluctant to attend school. Moreover, classmates may feel free to tease the child. A useful compendium of educational accommodations is available at http://www.tourettesyndrome.net/education.htm
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Educating peers may be equally important. Many clinicians actively encourage patients, families, and teachers to educate peers and classmates about TS. It is remarkable what can be tolerated in the classroom and on the playground when teachers and peers simply know what the problem is and learn to disregard it.
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Psychopharmacologic Intervention
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Table 44–3 depicts the attributes of medications regularly used to treat tic disorder. Dopamine D2 receptor antagonists are the most predictably effective tic-suppressing agents over the short-term. Among the typical neuroleptics, haloperidol and pimozide have the most favorable data demonstrating efficacy. Long-term experience has been less favorable, and the “reflexive” use of these agents should be avoided. Common potential side effects are tardive dyskinesia, acute dystonia, sedation, depression, school and social phobia, and/or weight gain. In many instances, by starting at low dose and adjusting the dosage upwards slowly, clinicians can avoid these side effects. The goal should be to use as little medication as possible to render the tics “tolerable.” Attempts to stop the tics completely often risk over-medication.
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Due to the extrapyramidal side effects associated with typical neuroleptics, atypical neuroleptics, such as risperidone, olanzapine and ziprasidone are now the most widely used medications to treat tic symptoms. These agents have potent 5-HT2 blocking effects as well as more modest blocking effects on dopamine D2. Double-blind clinical trials have supported the efficacy of risperidone, olanzapine, and ziprasidone. Risperidone and olanzapine are often associated with weight gain and sedation. Ziprasidone use can be associated with QT prolongation in children, so serial monitoring with electrocardiograms may be necessary.
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Clonidine and guanfacine are potent α2-receptor agonists that are thought to reduce central noradrenergic activity. Although less effective in relieving tics compared to the neuroleptic medication, α2-receptor agonists have the advantage of also improving comorbid ADHD symptoms in patients with tics. The principal side effect associated with clonidine is sedation, which occurs in 10–20% of subjects. It abates with continued use. Other side effects include dry mouth, transient hypotension, and rare episodes of worsening behavior. To reduce the likelihood of symptom or blood pressure rebound, clonidine should be tapered and not withdrawn abruptly. Guanfacine is generally preferred to clonidine because it is less sedating and not associated with rebound hypertension following withdrawal. In extreme cases, botulinum toxin injections temporarily weaken muscles associated with severe motor or vocal tics. The most common sites of injection are the neck (for motor tics) and shoulders and throat (for vocal tics).
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When comorbid ADHD is the most impairing to a patient presenting with comorbid tics, the stimulants methylphenidate, d-amphetamine, and Adderall are still first line agents for the medical management of ADHD. While most patients with both ADHD and a preexisting tic disorder do well on stimulants, clinical case reports and controlled studies indicate that some children with ADHD may exhibit tics de novo or experience a worsening of tics when exposed to a stimulant. Based on a large multisite randomized, controlled clinical trial, the combination of clonidine and methylphenidate is efficacious. Nonstimulants used in ADHD include atomoxetine, tricyclic antidepressants (desipramine and nortriptyline), atypical antidepressants such as bupropion, clonidine, and guanfacine.
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Psychotherapeutic Interventions
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Habit reversal training (HRT) is the first psychotherapeutic intervention that has shown promise in reducing tic severity in patients with TS. HRT significantly reduces tic symptoms in adults with TS when compared to supportive therapy in randomized, unblinded, wait-list controlled clinical trials. HRT has shown promise in uncontrolled trials among children with TS.
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HRT consists of two main components: (1) awareness training and (2) competing response practice. Awareness training consists of 4 components designed to increase an individual's awareness of his own tics. These components include (1) response description—in which the patient learns how to describe tic movements and re-enacts them into a mirror; (2) response detection—in which the therapist aids the patient in tic detection by pointing out each tic immediately after it occurs in the session; (3) early warning procedure—in which an individual learns how to identify the earliest signs of tic occurrence; and (4) situational awareness training—in which an analysis is conducted to identify the high-risk situations when tics are most likely to occur. Competing response practice involves teaching individuals to produce an incompatible physical response (i.e., isometric contraction of tic-opposing muscles) upon the urge to perform a tic.
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Neurosurgical Interventions
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Neurosurgical interventions for TS are reserved for adults with intractable tics that severely affect social functioning. Originally, neurosurgical lesioning procedures were attempted to treat the most severe cases of TS. Deep brain stimulation, a relatively reversible, stereotactic technique, used to treat other movement disorders, has become the preferred method of neurosurgical treatment for medically intractable tics. Deep brain stimulation has several advantages over previous neurosurgical lesioning procedures in that it lacks many of the permanent complications typically associated with lesioning procedures (the electrodes can be removed), lends access to many surgically inaccessible sites, and allows for bilateral stimulation. It holds great promise for adult patients with intractable tics. However, in using Deep brain stimulation for tics, neither the appropriate site of electrode placement nor the electrode stimulation parameters have been established in carefully controlled clinical studies. The preferred sites of electrode placement are either the midline thalamic nuclei or the globus pallidus, pars internus (GPi). Case reports indicate a 50–80% improvement in tic frequency following the procedure. Every possible medical option to treat tics beforehand should be exhausted.
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Woods DW: Habit reversal treatment manual for tic disorders. In: Woods DW,Miltenberger RG (eds).Tic Disorders, Trichotillomania, and Other Repetitive Behavior Disorders: Behavioral Approaches to Analysis and Treatment. Boston: Kluwer Academic Publishers, 2001, pp. 97–132.
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The onset of TS is usually characterized by simple, transient motor tics that affect the face (typically eye blinking) around 5–7 years of age. Over time, simple motor tics generally progress in a rostrocaudal direction affecting other areas of the face, followed by the head, neck, arms, and lastly and less frequently, the lower extremities. With time, vocal tics often appear, tics become increasingly complex, and premonitory urges are experienced. TS symptoms generally peak in severity between the ages of ten and twelve. Tic severity, however, typically dissipates with the onset of adolescence. The reduction in TS severity generally ends by the early twenties. Although a small minority of TS patients experience catastrophic outcomes in adulthood, on the whole, individuals rarely experience either a sustained worsening or improvement of their symptoms after the third decade of life. One-half to two-thirds of individuals with TS experience a marked reduction of symptoms by late adolescence and early twenties, and one-third to one-half of these patients become virtually asymptomatic in adulthood. Figure 44–2 diagrams the general course of tic severity of TS patients through the first two decades of their illness.
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Given that tics in children are often ephemeral, producing substantial social and educational impairment when the tics are at their worst but little afterwards, the importance of minimizing social consequences (peer teasing, poor self-esteem, and social withdrawal) and educational impairment can not be overstated in determining long-term outcome. The proper management of, and vigilance for, psychiatric conditions highly comorbid with tic disorder, such as ADHD and OCD (that currently are more effectively treated) are also crucial. Ensuring that patients with a history of tic disorders refrain from using substances known to induce tics such as amphetamines or crack/cocaine is also likely to improve their prognosis.