Prevalence of Tics in Schoolchildren in Central Spain: A Population-Based Study

Tic disorders constitute a neurodevelopmental disorder of childhood. This study sought to determine the prevalence of tic disorders in a school-based sample. A randomized sample of 1158 schoolchildren, based on clusters (classrooms) in the province of Burgos (Spain), was identified on a stratified sampling frame combining types of educational center and setting (mainstream schools and special education), using a two-phase approach (screening and diagnosis ascertainment by a neurologist). Tics with/without impairment criterion were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders criteria. In mainstream schools, tics were observed in 125/741 students (16.86%; 95% confidence interval, 14.10-19.63), and were more frequent in boys (87/448, 19.42%; 95% confidence interval, 15.64-23.19) compared with girls (38/293, 12.96%; 95% confidence interval, 8.95-16.98; P = 0.03). In special education centers, tics disorders were observed in 11/54 of children (20.37%; 95% confidence interval, 8.70-32.03). Overall, tics with impairment criteria were less frequent than tics without impairment criteria (4.65% vs 11.85%, P < 0.0001). The most frequent diagnoses involved chronic motor tics (6.07%) and Tourette syndrome (5.26%). Tic disorders are common in childhood, and the use or nonuse of impairment criteria exerts a significant impact on tic prevalence estimates

Tremor in School-Aged Children: A Cross-Sectional Study of Tremor in 819 Boys and Girls in Burgos, Spain

Background: Mild hand tremor occurs in most normal adults. There are no surveys of the prevalence or clinical correlates of such tremor among children. Methods: A cross-sectional study of tics, tremor and other neurological disorders was conducted in Spanish children; thus, 819 schoolchildren in Burgos, Spain, drew Archimedes spirals with each hand. Tremor in spirals was rated (0–2) by a blinded neurologist and an overall tremor rating (0–4) was assigned. Results: The mean age was 10.9 ± 3.1 years. A tremor rating of 1 (mild tremor) was present in either hand in 424 (51.7%) children, and in both hands in 88 (10.7%) children. Higher tremor ratings were very uncommon. The overall tremor rating was higher in boys than girls (1.31 ± 0.41 vs. 1.22 ± 0.34, p = 0.002) and correlated weakly yet significantly with age (ρ = 0.09, p = 0.01). Within subjects, the left hand spiral rating was greater than the right (p < 0.001). Conclusions: In this cross-sectional study of 819 Spanish schoolchildren, mild tremor was commonly observed. As in adults, males had more tremor than females, tremor scores increased with age, and tremor scores were higher in the left than right arm, demonstrating that these clinical correlations seem to be more broadly generalizable to children. The functional significance of tremor in children, particularly as it relates to handwriting proficiency, deserves additional scrutiny.This research was supported by National Institutes of Health Grants R01 NS39422 and Sanidad Castilla y León (SACYL), Biomedicine Project GRS 157-A, Health Research Grant PI 070846, and European General Development Cofunding

Association of Tic Disorders with Poor Academic Performance in Central Spain: A Population-Based Study

Objective: To analyze the association between tic disorders and poor academic performance in school-aged children. Study design: This was a cross-sectional, observational study conducted in a randomly selected sample of mainstream school-aged children (aged 6-16 years). The sampling frame included different types of schools and educational levels. Children with poor academic performance (eg, repeating a grade, special needs), and tic disorders (defined based on Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision criteria) were identified. Children with and without tics and children with and without poor academic performance were compared in terms of clinical features (ie, medical history and neurologic and psychiatric comorbidities), school, and environmental characteristics. Logistic regression analyses were performed using school performance (dependent variable) and tic disorders (independent variable), after adjusting for confounding variables. Results: The study cohort comprised 1867 children (mean age, 10.9 + 2.9 years; 1007 males [53.9%]). Tics were present in 162 children (8.6%), and poor academic performance was noted in 223 (11.9%). Overall poor academic performance was associated with age (OR, 1.71; P < .0001), television viewing (OR, 5.33; P = .04), attention deficit hyperactivity disorder (OR, 1.38; P < .0001), and family history of school dysfunction (OR, 2.43; P = .02) and was negatively associated with higher IQ score (OR, 0.90; P < .0001) and tic disorders (OR, 0.29; P = .01). Conclusion: After adjusting for other covariates, the presence of tic disorders was not associated with poor academic performance in our cohort. Early academic support and modification of environmental characteristics are needed for children at higher risk for school dysfunction, to enhance academic performance.Supported by SACYL, Biomedicine project GRS 157-A, Health Research Grant PI 070846, and the European General Development Co-funding