Tic disorders Health Article

Definition

Tic disorders are characterized by the persistent presence of tics, which are abrupt, repetitive involuntary movements and sounds that have been described as caricatures of normal physical acts. The best known of these disorders is Tourette's disorder, or Tourette's syndrome.

Description

Tics are sudden, painless, nonrhythmic behaviors that are either motor (related to movement) or vocal and that appear out of context— for example, knee bends in science class. They are fairly common in childhood; in the vast majority of cases, they are temporary conditions that resolve on their own. In some children, however, the tics persist over time, becoming more complex and severe.

Tics may be simple (using only a few muscles or simple sounds) or complex (using many muscle groups or full words and sentences). Simple motor tics are brief, meaningless movements like eye blinking, facial grimacing, head jerks or shoulder shrugs. They usually last less than one second. Complex motor tics involve slower, longer, and more purposeful movements like sustained looks, facial gestures, biting, banging, whirling or twisting around, or copropraxia (obscene gestures).

Simple phonic tics are meaningless sounds or noises like throat clearing, coughing, sniffling, barking, or hissing. Complex phonic tics include syllables, words, phrases, and such statements as "Shut up!" or "Now you've done it!" The child's speech may be abnormal, with unusual rhythms, tones, accents or intensities. The echo phenomenon is a tic characterized by the immediate repetition of one's own or another's words. Coprolalia is a tic made up of obscene, inappropriate or aggressive words and statements. It occurs in fewer than 10% of people with tic disorders.

Children under the age of 10 with simple tics find them to be difficult to suppress, or control. Many older patients and children with complex tics describe feeling strong sensory urges in their joints, muscles and bones that are relieved by the performance of a motor tic in that particular body part. These patients also report inner conflict over whether and when to yield to these urges. A sensation of relief and reduction of anxiety frequently follows the performance of a tic. Unless the tic disorder is very severe, most people with tics can suppress them for varying periods of time.

Motor and vocal tics may be worsened by anxiety, stress, boredom, fatigue, or excitement. Some people have reported that tics are intensified by premenstrual syndrome, additives in food, and stimulants. The symptoms of tic disorders may be lessened while the patient is asleep. Cannabis (marijuana), alcohol, relaxation, playing a sport, or concentrating on an enjoyable task are also reported to reduce the severity and frequency of symptoms.

Tics are the core symptom shared by transient tic disorder, chronic motor or vocal tic disorder, and Tourette's disorder. It is the severity and course that distinguishes these disorders from one another. The age of onset for these disorders is between two and 15 years. In 75% of Tourette's disorder patients, the symptoms appear by age 11.