Today the full-blown case of TS is unlikely to be confused with any other disorder. However, only a decade ago TS was frequently misdiagnosed as schizophrenia, obsessive-compulsive disorder, Sydenham's chorea, epilepsy, or nervous habits. The differentiation of TS from other tic syndromes may be no more than semantic, especially since recent genetic evidence links TS with multiple tics. Transient tics of childhood are best defined in retrospect. At times it may be difficult to distinguish children with extreme attention deficit hyperactivity disorder (ADHD) from TS. Many ADHD children, on close examination, have a few phonic or motor tics, grimace, or produce noises similar to those of TS. Since at least half of the TS patients also have attention deficits and hyperactivity as children, a physician may well be confused. However, the treating doctor should be aware of the potential dangers of treating a possible case of TS with stimulant medication. On rare occasions the differentiation between TS and a seizure disorder may be problematic. The symptoms of TS sometimes occur in a rather sharply separated paroxysmal manner and may resemble automatisms. TS patients, however, retain a clear consciousness during such paroxysms. If the diagnosis is in doubt, an EEG may be useful. We have seen TS in association with a number of developmental and other neurological disorders. It is possible that central nervous system injury from trauma or disease may cause a child to be vulnerable to the expression of the disorder, particularly if there is a genetic predisposition. Autistic and retarded children may display the entire gamut of TS symptoms, but whether an autistic or retarded individual requires the additional diagnosis of TS may remain an open question until there is a biological or other diagnostic test specifically for TS. In older patients, conditions such as Wilson's disease, tardive dyskinesia, Meige's syndrome, chronic amphetamine abuse, and the stereotypic movements of schizophrenia must be considered in the differential diagnosis. The distinction can usually be made by taking a good history or by blood tests. Since more physicians are now aware of TS, there is a growing danger of overdiagnosis or over-treatment. Prevailing diagnostic criteria would require that all children with suppressible multiple motor and phonic tics, however minimal, of at least one year, should be diagnosed as having TS. It is up to the clinician to consider the effect that the symptoms have on the patient's ability to function as well as the severity of associated symptoms before deciding to treat with medication. TABLE 1. RANGE OF SYMPTOMS OF TS Motor Simple motor tics: fast, darting, and meaningless. Complex motor tics: slower, may appear purposeful Vocal Simple vocal tics: meaningless sounds and noises. Complex vocal tics: linguistically meaningful utterances such as words and phrases (including coprolalia, echolalia, and palilalia). Behavioral and Developmental Attention deficit hyperactivity disorder, obsessions and compulsions, emotional problems, irritability, impulsivity, aggressivity, and self-injurious behaviors; various learning disabilities Symptomatology The varied symptoms of TS can be divided into motor, vocal, and behavioral manifestations (Table 2). Complex motor tics can be virtually any type of movement that the body can produce including gyrating, hopping, clapping, tensing arm or neck muscles, touching people or things, and obscene gesturing. At some point in the continuum of complex motor tics, the term "compulsion" seems appropriate for capturing the organized, ritualistic character of the actions. The need to do and then redo or undo the same action a certain number of times (e.g., to stretch out an arm ten times Definitions of Tic Disorders Tics are involuntary, rapid, repetitive, and stereotyped movements of individual muscle groups. They are more easily recognized than precisely defined. Disorders involving tics generally are divided into categories according to age of onset, duration of symptoms, and the presence of vocal or phonic tics in addition to motor tics. Transient tic disorders often begin during the early school years and can occur in up to 15% of all children. Common tics include eye blinking, nose puckering, grimacing, and squinting. Transient vocalizations are less common and include various throat sounds, humming, or other noises. Childhood tics may be bizarre, such as licking the palm or poking and pinching the genitals. Transient tics last only weeks or a few months and usually are not associated with specific behavioral or school problems. They are especially noticeable with heightened excitement or fatigue. As with all tic syndromes, boys are three to four times more often afflicted than g! irls. While transient tics by definition do not persist for more than a year, it is not uncommon for a child to have series of transient tics over the course of several years. Chronic tic disorders are differentiated from those that are transient not only by their duration over many years, but by their relatively unchanging character. While transient tics come and go - with sniffing replaced by forehead furrowing or finger snapping, chronic tics - such as contorting one side of the face or blinking - may persist unchanged for years. Chronic multiple tics suggest that an individual has several chronic motor tics. It is often not an easy task to draw the lines between transient tics, chronic tics, and chronic multiple tics. Tourette Syndrome (TS), first described by Gilles de la Tourette, can be the most debilitating tic disorder, and is characterized by multiform, frequently changing motor and phonic tics. The prevailing diagnostic criteria include onset before the age of 21; recurrent, involuntary, rapid, purposeless motor movements affecting multiple muscle groups; one or more vocal tics; variations in the intensity of the symptoms over weeks to months (waxing and waning); and a duration of more than one year. While the criteria appear basically valid, they are not absolute. First, there have been rare cases of TS which have emerged later than age 21. Second, the concept of "involuntary" may be hard to define operationally, since some patients experience their tics as having a volitional component - a capitulation to an internal urge for motor discharge accompanied by psychological tension aefore writing, to even up, or to stand up and push a chair into "just the right position") is compulsive in duality and accompanied by considerable internal discomfort. Complex motor tics may greatly impair school work, e.g., when a child must stab at a workbook with a pencil or must go over the same letter so many times that the paper is worn thin. Self-destructive behaviors, such as head banging, eye poking, and lip biting, also may occur. Vocal tics extend over a similar spectrum of complexity and disruption as motor tics ( The most socially distressing complex vocal symptom is coprolalia, the explosive utterance of foul or "dirty" words or more elaborate sexual and aggressive statements. While coprolalia occurs in only a minority of TS patients (from 5-40%, depending on the clinical series), it remains the most well known symptom of TS. It should be emphasized that a diagnosis of TS does not require that coprolalia is present. Some TS patients may have a tendency to imitate what they have just seen (echopraxia), heard (echolalia), or said (palilalia). For example, the patient may feel an impulse to imitate another's body movements, to speak with an odd inflection, or to accent a syllable just the way it has been pronounced by another person. Such modeling or repetition may lead to the onset of new specific symptoms that will wax and wane in the same way as other TS symptoms. TABLE 2. EXAMPLES OF MOTOR SYMPTOMS Simple motor tics Eye blinking, grimacing, nose twitching, lip pouting, shoulder shrugging, arm jerking, abdominal tensing, kicking, finger movements, jaw snapping, tooth clicking, frowning, tensing parts of the body, and rapid jerking of any part of the body. Complex motor tics Hopping, clapping, touching objects (or others or self), throwing, arranging, gyrating, bending, "dystonic" postures, biting the mouth, the lip, or the arm, headbanging, arm thrusting, striking out, picking scabs, writhing movements, rolling eyes upwards or side-to-side, making funny expressions, sticking out the tongue, kissing, pinching, writing over-and-over the same letter or word, pulling back on a pencil while writing, and tearing paper or books. Copropraxia "Giving the finger" and other obscene gestures. Echopraxia Imitating gestures or movements of other people. TABLE 3. EXAMPLES OF VOCAL SYMPTOMS Simple vocal tics Coughing, spitting, screeching, barking, grunting, gurgling, clacking, whistling, hissing, sucking sounds, and syllable sounds such as "uh, uh," "eee," and "bu." Complex vocal tics "Oh boy," "you know," "shut up," "you're fat," "all right," and "what's that." or any other understandable word or phrase Rituals Repeating a phrase until it sounds "just right" and saying something over 3 times. Speech atypicalities Unusual rhythms, tone, accents, loudness, and very rapid speech. Coprolalia Obscene, aggressive, or otherwise socially unacceptable words or phrases. Palilalia Repeating one's own words or parts of words. Echolalia Repeating sounds, words, or parts of words of others. The symptoms of TS can be characterized as mild, moderate, or severe by their frequency, their complexity, and the degree to which they cause impairment or disruption of the patient's ongoingctivities and daily life. For example, extremely frequent tics that occur 20-30 times a minute, such as blinking, nodding, or arm flexion, may be less disruptive than an infrequent tic that occurs several times an hour, such as loud barking, coprolalic utterances, or touching tics. There may be tremendous variability over short and long periods of time in symptomatology, frequency, and severity. Patients may be able to inhibit or not feel a great need to emit their symptoms while at school or work. When they arrive home, however, the tics may erupt with violence and remain at a distressing level throughout the remainder of the day. It is not unusual for patients to "lose" their tics as they enter the doctor's office. Parents may plead with a child to "show the doctor what you do at home," only to be told that the youngster "just doesn't feel like doing them" or "can't do them" on command. Adults will say "I only wish you could see me outside of your office," and family members will heartily agree. A patient with minimal symptoms may display more usual severe tics when the examination is over. Thus, for example, the doctor often sees a nearly symptom-free patient leave the office who begins to hop, flail, or bark as soon as the street or even the bathroom is reached. In addition to the moment-to-moment or short-term changes in symptom intensity, many patients have oscillations in severity over the course of weeks and months. The waxing and waning of severity may be triggered by changes in the patient's life; for example, around the time of holidays, children may develop exacerbations that take weeks to subside. Other patients report that their symptoms show seasonal fluctuation. However, there are no rigorous data on whether life events, stresses, or seasons, in fact, do influence the onset or offset of a period of exacerbation. Once a patient enters a phase of waxing symptomatology, a process seems to be triggered that will run its course - usually within 1-3 months. In its most severe forms, patients may have uncountable motor and vocal tics during all their waking hours with paroxysms of full-body movements, shouting, or self-mutilation. Despite that, many patients with severe tics achieve adequate social adjustment in adult life, although usually with considerable emotional pain. The factors that appear to be of importance with regard to social adaptation include the seriousness of attentional problems, intelligence, the degree of family acceptance and support, and ego strength more than the severity of motor and vocal tics. In adolescence and early adulthood, TS patients frequently come to feel that their social isolation, vocational and academic failure, and painful and disfiguring symptoms are more than they can bear. At times, a small number may consider and attempt suicide. Conversely, some patients with the most bizarre and disruptive symptomatology may achieve excellent social, academic, and vocational adjustments. Associated Behaviors and Cognitive Difficulties As well as tics, there are a variety of behavioral and psychological difficulties that are experienced by many, though not all, patients with TS. Those behavioral features have placed TS on the border between neurology and psychiatry, and require an understanding of both disciplines to comprehend the complex problems faced by many TS patients. The most frequently reported behavioral problems are attentional deficits, obsessions, compulsions, impulsivity, irritability, aggressivity, immaturity, self-injurious behaviors, and depression. Some of the behaviors (e.g., obsessive compulsive behavior) may be an integral part of TS, while others may be more common in TS patients because of certain biological vulnerabilities (e.g., ADHD). Still others may represent responses to the social stresses associated with a multiple tic disorder or a combination of biological and psychological reactions. Obsessions and Compulsions Although TS may present itself purely as a disorder of multiple motor and vocal tics, many TS patients also have obsessive-compulsive (OC) symptoms that may be as disruptive to their lives as the tics - sometimes even more so. There is recent evidence that obsessive-compulsive symptomatology may actually be another expression of the TS gene and, therefore, an integral part of the disorder. Whether this is true or not, it has been well documented that a high percentage of TS patients have OC symptoms, that those symptoms tend to appear somewhat later than the tics, and that they may be seriously impairing. The nature of OC symptoms in TS patients is quite variable. Conventionally, obsessions are defined as thoughts, images, or impulses that intrude on consciousness, are involuntary and distressful, and while perceived as silly or excessive, cannot be abolished. Compulsions consist of the actual behaviors carried out in response to the obsessions or in an effort to ward them off. Typical OC behaviors include rituals of counting, checking things over and over, and washing or cleaning excessively. While many TS patients do have such behaviors, there are other symptoms typical of TS patients that seem to straddle the border between tics and OC symptoms. Examples are the need to "even things up," to touch things a certain number of times, to perform tasks over and over until they "feel right," as well as self-injurious behaviors. Attention Deficit Hyperactivity Disorder (ADHD) Up to 50% of all children with TS who come to the attention of a physician also have attention deficit hyperactivity disorder (ADHD), which is manifested by problems with attention span, concentration, distractibility, impulsivity, and motoric hyperactivity. Attentional problems often precede the onset of TS symptoms and may worsen as the tics develop. The increasing difficulty with attention may reflect an underlying biological dysfunction involving inhibition and may be exacerbated by the strain of attending to the outer world while working hard to remain quiet and still. Attentional problems and hyperactivity can profoundly affect school achievement. At least 30-40% of TS children have serious school performance handicaps that require special intervention, and children with both TS and ADHD are especially vulnerable to serious, long term educational impairment. Attention deficits may persist into adulthood and together with compulsions and obsessions can seriously impair job performance. Emotional Lability, Impulsivity, and Aggressivity Some TS patients (percentages vary greatly in different studies) have significant problems with labile emotions, impulsivity, and aggression directed to others. Temper fits that include screaming, punching holes in walls, threatening others, hitting, biting, and kicking are common in such patients. Often they will be the patients who also have ADHD, which makes impulse control a considerable problem. At times the temper outbursts can be seen as reactions to the internal and external pressures of TS. A specific etiology for such behavioral problems is, however, not well understood. Nevertheless, they create much consternation in teachers and great anguish both to TS patients themselves and to their families. The treating physician or counselor is often asked whether those behaviors are involuntary, as tics are, or whether they can be controlled. Rather than trying to make such a distinction, it is perhaps more helpful to think of such patients as having a "thin barrier" between aggressive thoughts and the expression of those thoughts through actions. Those patients may experience themselves as being out of control, a concept that is as frightening to themselves as it is to others. Management of those behaviors is often difficult and may involve adjustment of medications, individual therapy, family therapy, or behavioral retraining. The intensity of those behaviors often increases as the tics wax and decreases as the tics wane. Etiology The most intensive research in relation to etiology has focused on neurochemical alterations in the brain. Multiple neurochemical systems have been implicated by pharmacologic and metabolic evidence. The most convincing evidence for dopaminergic involvement has come from the dramatic response to haloperidol and other neuroleptics such as pimozide, flupenazine, and penfluridol, as well as exacerbations produced by stimulant medications. Findings of reduced levels of dopamine metabolites in cerebrospinal fluid (CSF) have led investigators to believe that TS results from a hypersensitivity of postsynaptic dopamine receptors. Serotonergic mechanisms have been suggested on the basis of reduced CSF serotonin metabolites. Since systems relying on neurotransmitters send projections to the substantia nigra and the striatum, they could play an important role in the pathophysiology of TS. Medications affecting that system seem somewhat effective for obsessions but have inconsistent effects on tics. The role of the cholinergic system is clouded by contradictory reports. Enhancing cholinergic function by use of physostigmine has been associated both with the improvement and the worsening of TS. Elevated levels of red blood cell choline have been found in TS patients and their relatives, but the significance is unclear. Investigation of the GABAergic system suggests that it may be implicated. The proximity and connections between the GABA and dopamine systems support the possibility of an interrelationship. Response to clonazepam (a GABAergic agent) has been positive in some cases. Yet other GABAergic drugs such as diazepam do not have such positive effects. Noradrenergic mechanisms have been most persuasively implicated by observations that clonidine, a drug that inhibits noradrenergic functioning by the stimulation of an autoreceptor, may improve motor and phonic symptoms. Noradrenergic involvement has also been suggested by the exacerbation of the syndrome by stress and anxiety. The use of functional neuroimaging techniques such as positron emission tomography may help clarify many physiologic relationships and identify important anatomical areas in the near future. Stimulant Medications A particularly important risk factor in tics and TS is the use of stimulant medication. Over 25% of all TS patients in some cohorts have had a course of stimulation medication early in the emergence of their behavioral or tic symptoms because they have been diagnosed as having ADHD. Over the last several years, series of cases have been reported in which the use of stimulants (methylphenidate, dextroamphetamine, and pemoline) has been correlated with the onset of motor and phonic tics. There is also chemical evidence to support the observation that stimulants will increase the severity of tics in 25-50% of TS patients. In many cases, the tics associated with stimulant medication will disappear with the reduction or termination of the medication. It is more controversial whether stimulants can actually trigger or produce prolonged chronic multiple tics or TS that will persist following their termination. However, cases have been reported in which that seems to have occurred. Available information thus indicates that stimulants should be used cautiously with ADHD children who have a close relative with tics, should generally be avoided with ADHD children with a first-degree relative with TS, and should be terminated with the onset of tics in children who previously were tic-free. Children and parents should be educated concerning the risks versus benefits in each case prior to being treated with stimulants. Alternatives such as behavioral management, environmental manipulation, and/or other types of medication should be considered carefully. Epidemiology and Genetics While once thought to be rare, TS is now seen as a relatively common disorder affecting up to one person in every 2,500 in its complete form and three times that number in its partial expressions that include chronic motor tics and some forms of obsessive-compulsive disorder. The question of the familial transmission of TS was first raised in the original 19th century descriptions of the disorder, but a genetic basis for TS was not considered seriously until recently. Several genetic studies have now been reported and other rigorous studies are now well enough along to draw several important conclusions. Those studies have investigated many families in which TS and other tic disorders have been transmitted over several generations. Based on available information, it is now clear that TS is a genetic disorder. The vulnerability to TS is transmitted from one generation to another. When we speak of "vulnerability," we imply that the child receives the genetic or constitutional basis for developing a tic disorder; the precise type of disorder or severity may be different from one generation to another. That vulnerability is transmitted by either mothers or fathers and can be passed on to either sons or daughters. When one parent is a carrier or has TS, it appears that there is about a 50-50 chance that a child will receive the genetic vulnerability from that parent. That pattern of inheritance is described as autosomal dominant. However, not everyone who inherits the genetic vulnerability will express any of the symptoms of TS. There is a 70% chance that female gene carriers will express any of the symptoms of TS. For a male gene carrier, there is a 99% chance of showing some clinical expression of the gene. The degree of expression is described as penetrance. In males, the penetrance is higher than in females; thus, males are more likely to have some form of expression of the genetic vulnerability. There is a full 30% chance of female gene carriers showing no symptoms at all. For males, the figure is 1%. There is a range of forms in which the vulnerability may be expressed that includes full-blown TS, chronic multiple tics, and, as most recently recognized, obsessive-compulsive disorder. Some individuals have TS (or chronic tics) and obsessive-compulsive disorder together; others may have the conditions singly. There are also differences between the sexes in the form of expression of the TS gene. Males are more likely to have TS or tics; females are more likely to have obsessive-compulsive disorder; however, both males and females may have any combination or severity. The severity of the disorder is also highly variable. Most individuals who inherit the TS genetic vulnerability have very mild conditions for which they do not seek medical attention. Researchers are actively engaged in searching for the chromosomal location of the TS gene of affected individuals. At present, there is no genetic or biochemical test to determine if a person with TS or an unaffected individual carries the gene. There is no prenatal test for the vulnerability to TS. When scientists succeed in locating the gene, such tests may become available. Non-Genetic Contributions The individual variations in character, course, and degree of severity by which TS is manifested cannot be explained by genetic hypotheses alone. Furthermore, it appears that about 10-15% of TS patients do not acquire the disorder genetically. Thus, non-genetic factors are also responsible, both as causes and as modifiers of TS. Non-genetic factors that have been implicated include such stressful processes or events during the prenatal, perinatal, or early life periods as fetal compromise and exposure to drugs or other toxins. Findings from one study in which decreased birth weights were observed in the affected co-twins of discordant monozygotic pairs lend further support to the influence of environmental factors. Clinical Assessment Of Tourette Syndrome Assessment of a case of TS involves far more than simple diagnosis. Since symptoms may fluctuate in severity and character from hour to hour, a thorough understanding of the patient may take a considerable amount of time. As the patient becomes more comfortable with the doctor, there will be less likelihood of symptom suppression or inhibition. Only when there is confidence in the physician is the patient likely to acknowledge the most frightening or bizarre symptoms. The nature, severity, frequency, and degree of disruption produced by the motor and vocal tics need to be carefully assessed from the time of their emergence until the present. Inquiries should be made about factors that may have worsened or ameliorated their severity. A critical question concerns the degree to which the tics have interfered with the patient's social, familial, and school or work experiences. In those respects interviews with families may be revealing and informative. During the evaluation of a patient with TS, the clinician must assess all areas of functioning to fully understand both difficulties and strengths. It is important to explore the presence of attentional and learning disabilities, a history of school and/or work performance, and relationships with family and peers. Before receiving the diagnosis, the patient and/or family may have thought he or she "was going crazy." The patient may have become extremely distressed by his or her own experiences and by the often negative responses evoked. Parents may have scolded, cajoled, ridiculed, threatened, and perhaps beaten the child to stop the "weird" and embarrassing behavior, and the emotional sequelae may affect the patient far beyond the period of childhood. During the evaluation of a child, therefore, family issues including parental guilt need to be addressed. Relevant factors elicited through careful diagnostic evaluation can be approached through clarification, education, and therapeutic discussion with the youngster and the family. Careful assessment of cognitive functioning and school achievement is indicated for children who have school problems. TS children with school performance difficulties often do not have clearly delineated learning disorders, and the average IQ of TS patients is normal. Rather, their problems tend to lie in the areas of attentional deployment, perseverance, and the ability to keep themselves and their work organized. Many have difficulties with penmanship (graphomotor skills) and compulsions that interfere with writing. Determining specific problem areas will help in the recommendation of alternatives (e.g., extended periods of time for tests, the use of a typewriter or the emphasis on oral rathe! r than written reports). The neurological examination should include documentation of neuromaturational difficulties and other neurological findings. About half of TS patients have non-localizing, so called "soft," neurological findings suggesting disturbances in the body scheme and integration of motor control. While such findings have no specific therapeutic implications, they are worth noting as "baseline" data since the use of medications such as haloperidol may cloud the neurological picture. The EEG is often abnormal in TS, but the EEG findings are nonspecific. Computed tomography of the brain produces normal results in people with TS. Thus, unless there is some doubt about the diagnosis or some complicating neurological factors, an EEG and a computed tomography are not necessary parts of the clinical evaluation. Additional studies that may be considered in the biological work-up include serum electrolytes, calcium, phosphorous, copper, ceruloplasmin, and liver function tests - all related to movement disorders of various types. In practice, however, they are rarely needed for the diagnosis. A behavioral pedigree of the extended family, including tics, compulsions, attentional problems and the like is useful. Previous medications must be reviewed in detail during assessment. If a child has received stimulant medications, it is important to determine what the indications for the medications were, whether there were any pre-existing tics or compulsions, and the temporal relation between the stimulants and the new symptoms. Catecholaminergic agonists are contained in other drugs, such as in decongestant combinations used in treating allergies and in medications used for asthma. If a patient with TS is on a stimulant or a drug containing an ephedrine like agent, discontinuation should be strongly considered.