**5.1 Indirect observations**

Majority of the studies regarding prevalence of tics based in indirect measures employs questionnaires for parents, teacher and patient; instruments self-administered for detect and draw characteristics of tics, as follows in Table 1.

#### **Tics are abnormal movements with the following characteristics:**

They are sudden, brief, and rapid

They are repetitive

They can be controlled voluntarily during short periods of time

They can change and affect other body parts periodically

They improve and worsen from time to time

The most common tics are eye blinking, elevating the eyebrows, twitching the nose and the mouth and shoulder shrugging, shaking the head, twitching the neck, touching objects, other people, or body parts (hair, nose, etc.), kicking the legs, throat clearing, sniffing, barking, and verbalizations.

**According to these characteristics:** 

Do you believe that your son/daughter has had tics? (yes or no) Do you believe that your son/daughter (or pupil) has tics? (yes or no)

Table 1. General structure used in questionnaires for tics detection.

broader field of behavior therapy have preferred indirect measures, such as clinical impression, self-report inventories and clinician-rated scales. The most commonly cited reasons for not using direct observation include concerns about generalization of observations made in clinic or research settings to other relevant settings, such as home or school53 and disagreement about the best methods for collecting and scoring direct observation data54. Although the empirical basis for these concerns is not firmly established, acquisition of data supporting the use of direct observation methods may encourage those outside behavior analysis to use direct observation as a primary assessment method rather

Studies in tics may be divided into three groups: 1) Studies made in clinical grounds, 2)

Studies of in-hospital population comprise patients with most severe symptoms, in different age groups and different methods of final diagnosis confirmation are used. Procedures used in large-scale screening studies make possible the elimination of potential selection bias. Large populations are studied using transparent and repetitive confirmation of diagnoses. Their validity is additionally checked in parallel validity studies. The highest prevalence of tics is obtained in studies involving schoolchildren. Data are gathered from multiple sources: from parents, teachers, and children, as well as videos, from classroom observation and diagnoses made by experienced clinicians. Epidemiological surveys of school-age children have shown tic rates ranging from 4% to 50%55. This instability in reported rates is perplexing and is probably more artifact than truth. For example, prevalence of tics increases if transient tics are taken into account56, if studies were made just in public awards and when children attending special education schools were studied57. Inversely, prevalence

Majority of the studies regarding prevalence of tics based in indirect measures employs questionnaires for parents, teacher and patient; instruments self-administered for detect and

The most common tics are eye blinking, elevating the eyebrows, twitching the nose and the mouth and shoulder shrugging, shaking the head, twitching the neck, touching objects, other people, or body parts (hair, nose, etc.), kicking the legs, throat clearing, sniffing,

Large-scale screenings and 3) Studies involving selectively school population.

than relying on potentially biased verbal self-reports.

of tics lowers after direct observation extends for a wide time58.

**Tics are abnormal movements with the following characteristics:** 

They can be controlled voluntarily during short periods of time They can change and affect other body parts periodically

Do you believe that your son/daughter has had tics? (yes or no) Do you believe that your son/daughter (or pupil) has tics? (yes or no) Table 1. General structure used in questionnaires for tics detection.

draw characteristics of tics, as follows in Table 1.

They improve and worsen from time to time

**5.1 Indirect observations** 

They are sudden, brief, and rapid

barking, and verbalizations. **According to these characteristics:** 

They are repetitive

The indirect measures of tic severity could seem inadequate and, as such, research that has relied exclusively on instruments designed for collection of indirect measures should be interpreted with caution.
