Disorders of Childhood: Tic Disorders
Tics are the name given to sudden, rapid, recurrent, nonrhythmic, stereotyped and involuntary behaviors that people may display. Examples of tics include repetitive and involuntary eye blinking or twitching, and similarly involuntary vocalization of words, Tics come in two flavors. They may be physical in nature, or vocal. Motor and vocal tics may be simple (i.e. involving only a few muscles or sounds at a time) or complex (i.e., involving multiple muscles, or full sentences and phrases). Tic Disorders are diagnosed when people have chronic (i.e., repeated across time) motor and vocal tics that interfere with their daily activities. Tourette's Syndrome, Chronic Motor or Vocal Tic Disorder, Transient Tic Disorder, and Tic Disorder Not Otherwise Specified (NOS) are all subtypes of Tic Disorders.
Children with a tic disorder may show repeated eye blinking; nose wrinkling; hand gesturing; repetitious touching/smelling an object, throat clearing, grunting, or sniffling. They may also have complex vocal tics such as vocal outbursts, repeating sound or words again and again, repeating the last-heard sound or phrase, and Coprolalia (suddenly saying socially unacceptable words or phrases) which is characteristic of the most famous tic disorder, Tourette's Syndrome. Compulsive behaviors (e.g., repeated tapping, counting, checking behaviors designed to reduce anxiety) are common across Tic Disorders.
According to the National Institute of Neurological Disorders and Stroke, approximately 200,000 Americans have Tourette's Syndrome, and as many as 1 in 100 have some form of Tic Disorder. Boys are more likely to be affected than girls. Tic Disorders usually start in early childhood, most often during school-age years (5-7 years old).
According to the DSM, children who are diagnosed with a Tic Disorder have tics (not caused by substance abuse or a medical condition) that occur multiple times each day. These tics are severe enough that they cause distress and/or impairment in daily functioning. Also, the DSM criteria state that Tic Disorder must begin before age 18 in order for the the diagnosis to apply.
The specific Tic Disorder diagnosed depends on the duration and variety tics, as well as the child's age when the tics began. Transient Tic Disorder includes motor and/or vocal tics that last for at least 4 weeks but not longer than 12 consecutive months. Chronic Motor or Vocal Tic Disorder, as the name suggests, is the presence of either a motor or vocal tic that lasts more than 12 consecutive months. Children with Tourette's have several motor tics and at least one vocal tic during 12 consecutive months. Tic Disorder NOS is reserved for children have tics that do not meet the criteria for the other diagnoses discussed.
Diagnosis of Tic Disorders
Children suspected of having a Tic Disorder should be thoroughly examined by a pediatrician who may order lab tests and an EEG (a method for monitoring brain activity) to help confirm the diagnosis. Research suggests that more than half of Tourette's patients show abnormal brain wave activity on their EEG tests.
Though EEG findings can be helpful, the core of any tic disorder involves the tic behaviors themselves. Accordingly, a large part of the diagnosis of a tic disorder requires that tic behaviors be observed, measured and documented. Children are monitored for tic behaviors at home and at school using time-sampling procedures and self-monitoring procedures. Time-sampling procedures involve outside observers who can record how many tics the child experiences within a given time interval, with multiple time intervals for data collection scheduled throughout the day. Self-monitoring procedures require children or adolescents to keep track of when and how often their tics occur (and obviously cannot be used with children who are not cognitively mature enough to engage in these tasks). Self-monitoring of tics, when appropriate, is doubly useful. It helps therapists and family members to measure tic behaviors so that progress can be documented. It also helps increase children's awareness of their tic behaviors, which tends to have a natural deterrent effect, and also helps them to monitor the effectiveness of treatment methods so as to determine which are most useful and effective.
Specific assessment tools used to measure tics may include:
The Motor Tic, Obsession and Compulsion, and Vocal Tic Evaluation (MOVES)
This self-report scale can be easily completed by children, adolescents, or adults. It yields measurements of Motor Tics, Vocal Tics, Obsessions (repetitive thoughts), Compulsions (repetitive behaviors), and Associated Symptoms.
Yale Global Tic Severity Scale
The Yale Global Tic Severity Scale evaluates the number, frequency, intensity, and complexity of motor and vocal tics. In addition, it assesses various psychological symptoms that may accompany tic disorders, such as depression and anxiety.
As suggested above by the reference to EEG findings, children with Tic Disorders may have abnormalities in brain functioning. For instance, these children may demonstrate impaired executive functioning ability (e.g., impaired ability to plan, make decisions, and inhibit inappropriate behavior) or a learning disorder such as dyslexia. For this reason, a comprehensive neuropsychological assessment is also recommended.
A neuropsychological assessment is a battery of tests performed by a Neuropsychologist (a clinical psychologist who specializes in tests) or a Psychometrist (a testing technician who works for a neuropsychologist) that can take several hours to complete. The battery is usually composed of multiple tests (some which are timed and other that are not timed) designed to measure different facets of cognition (thinking) such as the ability to pay attention, remember, make complex decisions, track information, so on. Neuropsychological tasks are not medical in nature. By comparing a child's performance on the tests to norms (performance standards obtained by testing other children of the same age), it is possible to detect very small functional impairments that even the best modern brain imaging scans cannot detect. The pattern of strengths and weaknesses uncovered allows clinicians to know quite a lot about how children's brains are functioning and what any detected deficits might mean for their development.