Tic prevalence by direct observation in an elementary school

Abstract

Introduction: Estimates of tic prevalence in community samples of children vary significantly. It is important to know the true prevalence of tics, as it aids in clinicians’ ability to counsel patients and families on the typical course of tics in those presenting for treatment. In this study, we directly observe elementary school children in the classroom setting in order to determine the prevalence of tics in the general school population.Methods: Participants were 215 children in kindergarten through fifth grade, including students from 5 first grade classrooms and 1 classroom each from the additional grades. Trained raters observed each child for three minutes, once monthly, for three consecutive months. Raters recorded whether tics were present, and if so, their type and frequency.Results: Prevalence over the 3 visits was 47%. Peak point prevalence was 35.1% for motor tics and 4.9% for phonic tics. Simple tics were more common than complex tics. Tic frequency was similar amongst the different grade levels observed. Tics seen at all 3 visits were uncommon and largely occurred in older children. The most common locations for tics were mouth, extremity, and eye. Variability in tic detection from one month to the next in a given student does not appear to reflect different phenotypes.Conclusion: These results largely confirm the results of Snider et al. (2002) and extend them to phonic tics. Both studies suggest that tics occur in a majority of children at some point in elementary school years. Tics lasting for a year or more—though not necessarily noticed by the child or parent—are also likely much more common than most epidemiological surveys would suggest.

Tics in ADHD

“…Third, they diagnosed tics based on reports from parents and teachers-with careful questioning by trained research staff-but only supplemented by direct examination at the research visits if tics were reported to be "moderate," "severe," or "Tourette-like." We know from our recent New Tics study and previous research that many tics not recognized by parents or teachers are identified when the child is observed by clinicians or trained research staff [4]. For all these reasons, probably even more children with ADHD had tics than the 43% reported by Law and Schchar.…”