Increased Susceptibility to Tics in Special Education School Children

Abstract

Source: Kurlan R, McDermott MP, Deeley C, et al. Prevalence of tics in school children and association with placement in special education. Neurology. 2001;57:1383–1388.The prevalence of tics in special education (SpEd) students and in a matched control sample of students in regular classroom programs (RegEd) was determined in a large-scale, community-based epidemiological study at the University of Rochester School of Medicine, Rochester, NY. Three RegEd subjects were randomly selected for every 1 SpEd subject. A total of 1,596 students (ages 8.5–17.5 yrs) drawn from the Rochester city school district and 9 surrounding Monroe County suburban public school districts were interviewed from November 1994 to March 1998. The disability classifications of SpEd students included learning disability (79%), speech impaired (14%), emotionally disturbed (5%), and other (2%). Interviews of 341 SpEd and 1,255 RegEd students were conducted by neuropsychological technicians trained to assess the presence and severity of tics, and to distinguish them from other movements and behaviors. To reduce the likelihood of drug-induced tics, children receiving stimulant medication were interviewed in the morning and parents were instructed not to administer the morning dose. Each technician had spent 3 months with a neurologist expert in movement disorders, observing approximately 75 children with tics prior to the study. Parent interviews were conducted in the school office or by telephone. RegEd and SpEd students were evaluated in the same time periods, and interviewers were blinded to educational placement. Tics were classified as either definite (observed) or probable (based on historical information), and motor or vocal.The proportion of tics in the SpEd and RegEd groups was 27% and 19.7%, respectively (P=.008). The weighted prevalence estimates for tics were 23.4% for SpEd and 18.5% for RegEd students. Including only definite tics, the SpEd group still had a higher proportion of tics. A higher percentage of students in SpEd (7%) met diagnostic criteria for Tourette syndrome than those in RegEd (3.8%). Thirty percent of students in the SpEd group were receiving stimulant medication compared to 7.5% of RegEd students. The authors conclude that tics are a common disorder in school children and are strongly associated with school dysfunction and they may represent an identifiable sign of an underlying brain development disorder which may contribute to academic difficulties.Tics are simple or complex, motor or vocal, transient or chronic, and definite, observed by the physician, or probable, only by history or report. Tourette syndrome is characterized by chronic tics, both motor and vocal, persisting for longer than 1 year.1 The prevalence of tics among children attending regular classes in the present study (18.5%) is higher than that previously quoted in the literature (4 to 16%),1 but the prevalence (27%) among children in special education is similar to that cited in a comprehensive review of tic disorders.2In the Rochester study, 30% of SpEd students were under treatment with stimulant medication, presumably for ADHD; a small proportion had taken methylphenidate on the day of the interview. A previous Rochester study3 involving 41 school children with tic disorders found that 11 (27%) had ADHD, and treatment with methylphenidate was the suspected cause of tics in 10 (25%). Despite recent studies that minimize a causal association between stimulants and tics,4 experience in practice and earlier studies endorse the occurrence of stimulant-induced tics in susceptible children, the effect being dose-related.5 Furthermore, tics and Tourette syndrome received no, or only passing, mention in the neurological literature and textbooks until the use of stimulants became popular in the 1960s.1 In the present study, stimulant discontinuance on the morning of the observation might reduce the frequency of drug-induced tics but is unlikely to eliminate them. It is prudent to monitor for tics during treatment of ADHD, and stimulants should be withheld or used conservatively with parental informed consent6 in patients with a personal or family history of tic disorders.Although only 11% of the study sample agreed to participate, and those who did may have opted to do so because they suspected their child might have tics, we should still pay particular attention to the results of this study. A realistic conclusion is that no matter what the type of classroom setting (special or regular education) we, along with parents and teachers, need to monitor school performance even more closely in children who manifest tics.