Tourette

Tourette syndrome Classification Characteristics Causes Diagnosis Screening Management Prognosis Epidemiology History and research directions

Characteristics

Tics are movements or sounds "that occur intermittently and unpredictably out of a background of normal motor activity",[13] having the appearance of "normal behaviors gone wrong".[14] The tics associated with Tourette's constantly change in number, frequency, severity and anatomical location. Waxing and waning—the ongoing 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.[8]

Coprolalia (the spontaneous utterance of socially objectionable or taboo words or phrases) is the most publicized symptom of Tourette's, but it is not required for a diagnosis of Tourette's and only about 10% of Tourette's patients exhibit coprolalia.[15] Echolalia (repeating the words of others) and palilalia (repeating one's own words) occur in a minority of cases,[8] while the most common initial motor and vocal tics are, respectively, eye blinking and throat clearing.

In contrast to the abnormal movements of other movement disorders (for example, choreas, dystonias, myoclonus, and dyskinesias), the tics of Tourette's are stereotypic, temporarily suppressible, nonrhythmic, and often preceded by an unwanted premonitory urge.[17] Immediately preceding tic onset, most individuals with Tourette's are aware of an urge,[18][19] similar to the need to sneeze or scratch an itch. Individuals describe the need to tic as a buildup of tension, pressure, or energy[19][20] which they consciously choose to release, as if they "had to do it"[21] to relieve the sensation[19] or until it feels "just right".[21][22] 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" or premonitory urges. Because of the urges that precede them, tics are described as semi-voluntary or "unvoluntary",[13] rather than specifically involuntary; they may be experienced as a voluntary, suppressible response to the unwanted premonitory urge.[15] Published descriptions of the tics of Tourette's identify sensory phenomena as the core symptom of the syndrome, even though they are not included in the diagnostic criteria.[20][23][24]

While individuals with tics are sometimes able to suppress their tics for limited periods of time, doing so often results in an explosion of tics afterward.[6] People with Tourette's may seek a secluded spot to release their symptoms, or there may be a marked increase in tics after a period of suppression at school or at work.[14] Some people with Tourette's 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.[13] 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.[25] 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,[6] the condition follows a fairly reliable course in terms of the age of onset and the history of the severity of symptoms. Tics may appear up to the age of eighteen, but the most typical age of onset is from five to seven.[8] A 1998 study published by Leckman et al of the Yale Child Study Center[26] showed that the ages of highest tic severity are eight to twelve (average ten), with tics steadily declining for most patients as they pass through adolescence.[22] The most common, first-presenting tics are eye blinking, facial movements, sniffing and throat clearing. Initial tics present most frequently in midline body regions where there are many muscles, usually the head, neck and facial region.[6] 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 and bilateral, and involve the extremities (e.g., flapping the hands).[27] Tics that appear 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 the first to see a child with tics.[8]

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.[22] Not all persons with Tourette's have ADHD or OCD or other comorbid conditions (co-occurring diagnoses other than Tourette's), although in clinical populations, a high percentage of patients presenting for care do have ADHD.[22][28] One author reports that a ten-year overview of patient records revealed about 40% of patients with Tourette's have "TS-only" or "pure TS", referring to Tourette syndrome in the absence of ADHD, OCD and other disorders.[29][30] Another author reports that 57% of 656 patients presenting with tic disorders had uncomplicated tics, while 43% had tics plus comorbid conditions.[14] "Full-blown Tourette's" is a term used to describe patients who have significant comorbid conditions in addition to tics