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A significant majority of children who have Tourette syndrome (TS) have a definite pattern to the convulsive tics which characterize the disorder, increasing in frequency and severity until a certain age and then decreasing. Of 42 children with TS born in the same year, the average was an increase in tics until the worst period at age 10, then a decrease until, by age 18, there were practically no tic episodes for nearly half of the group. Puberty did not seem to have any connection with the pattern., Objective. Prevalence studies indicate a 10-fold higher rate of Tourette syndrome (TS) among children compared with adults. The purpose of this investigation was to examine the course of tic severity during the first 2 decades of life. Method. A birth-year cohort of 42 TS patients followed at the Yale Child Study Center was recontacted an average of 7.3 years after their initial clinical evaluation. Data concerning the onset and course of tic severity until 18 years of age were available on 36 TS patients. A variety of statistical techniques were used to model aspects of the temporal patterning of tic severity. Results. Mean (SD) tic onset at 5.6 (2.3) years of age was followed by a progressive pattern of tic worsening. On average, the most severe period of tic severity occurred at 10.0 (2.4) years of age. In eight cases (22%), the frequency and forcefulness of the tics reached a severe level during the worst-ever period such that functioning in school was impossible or in serious jeopardy. In almost every case this period was followed by a steady decline in tic severity. By 18 years of age nearly half of the cohort was virtually tic-free. The onset of puberty was not associated with either the timing or severity of tics. Conclusions. A majority of TS patients displayed a consistent time course of tic severity. This consistency can be accurately modeled mathematically and may reflect normal neurobiological processes. Determination of the model parameters that describe each patient's course of tic severity may be of prognostic value and assist in the identification of factors that differentially influence the course of tic severity. Pediatrics 1998;102:14-19. Tourette syndrome, natural history, growth curve analysis, puberty. ABBREVIATIONS. TS, Tourette syndrome; YCSC, Yale Child Study Center Tic Disorders Clinic; ADHD, attention deficit-hyperactivity disorder; OCD, obsessive-compulsive disorder; CGI, Clinical Global Impression (scale); SES, socioeconomic status; YGTSS, Yale Global Tic Severity Scale; ARRTS, annual rating of relative tic severity; STOBS-R, Schedule for Tourette and Other Behavioral Syndromes, Adult-on-Child Version, Revised; MSRPF, Modified Schedule for Risk and Protective Factors., Epidemiologic studies have indicated a higher prevalence rate of Tourette syndrome (TS) among children compared with adults. In children, prevalence rates as high as 50 per 10 000 have been [...]

The effects of heat on tic symptoms were studied in a sample of 78 adults with Tourette syndrome. 62 men and 16 women completed a survey concerning the type, onset, and course of their tics. 10 adult male subjects also participated in a thermal challenge during which ambient temperature was raised from 22 [degrees] C to 35 [degrees] C following a control period. Of the 78, 24% or 19 reported increased tics upon exposure to heat. Compared to the remaining 59 subjects, there were no differences in sex distribution, current age, or overall course of illness. In the thermal challenge, there was general increase in tics that was correlated with sweat rate (r = .55, p = .001). This effect was prominent in 5 of 10 subjects (rs = .29 to .63). There were no mean differences in current age, age of onset, or current severity of symptoms between the five subjects of each group. Tic symptoms in a subgroup of patients with Tourette syndrome may be sensitive to heat. Abnormal heat regulation is not a likely explanation for the observed increase in tics. The increase may be due to normal heat-loss mechanisms through dopaminergic pathways.