Tics are abnormal, undesired spastic movements or vocalizations. These movements or vocalizations are repetitive, do not follow a rhythm, and are generally involuntary. Persistent motor or vocal tic disorder is a condition in which a person experiences single or multiple occurrences of either motor or verbal tics, but not both, for a period lasting more than one year. If a person experiences both motor and vocal tics for more than one year, the diagnosis would likely be Tourette’s disorder, or Tourette's syndrome, rather than persistent motor or vocal tic disorder. However, persistent (chronic) motor or vocal tic disorder is more common than Tourette's disorder.
For a person to be diagnosed with persistent motor or vocal tic disorder, the tics must have started before age 18. Tics are at least twice as common in boys as in girls, and symptoms usually begin before a child reaches puberty, with an average onset between the ages of 4 and 6. Symptoms tend to be at their most severe between the ages of 10 and 12 and improve as the child moves into adolescence.
Tics are often preceded by a premonitory urge, described a strong, uncomfortable and seemingly uncontrollable urge to move, followed by a release of tension once the tic has occurred. Some children also feel that their tic must be done in a certain way, and they will repeat the tic until it has been done “just right.” But not everyone who suffers experiences these urges and needs.
Tics can be either simple or complex. Simple motor tics are quick (milliseconds) and can include eye blinking, facial grimaces, repetitive and rapid shoulder shrugging, repetitive touching, or straightening the arms or legs. Simple vocal tics include throat clearing, sniffing, humming, and grunting. Complex tics last for a longer period (seconds) and may include a combination of simple tics, such as simultaneous head turning and eye blinking. Complex tics may also include repeating specific words or phrases.
Tics tend to worsen when a person feels anxious, excited, or exhausted. Similarly, tics may diminish when a person is calm and focused on a particular activity, such as schoolwork.
Tics may occur intermittently and change over time. Tic-free periods can last weeks or months. Those with mild or moderate tics often feel no distress or experience any impairment as a result of their tics. Although difficult to control, children are sometimes able to suppress tics for short periods of time. However, the tension and discomfort that builds during the suppression of a tic can only be relieved by allowing the tic to occur.
Treatment for a tic disorder is only necessary when the symptoms are severe enough to cause distress in a child or adolescent and interfere with their school functioning or social development. Treatment might include medication or cognitive-behavioral therapy (CBT) to reduce the presence and severity of symptoms as well as improve the distress a person experiences as a result of the tics. In particular, a form of CBT known as habit reversal training can help the child learn to identify situations that trigger their tics and methods to counter a premonitory urge. Practicing relaxation techniques can also help reduce the frequency of tics.