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.